Appendix A To Essay 11-01 -- Scientists Change Their Minds..., er..., Yet again!

 

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This Appendix used to belong to Essay Eleven Part One; it has been moved here since that Essay was becoming unwieldy.

 

In this section, I will be posting examples (in addition to those already listed in the main body of the above Essay) of scientists who have radically changed their minds, or where they have overthrown, questioned or rejected established dogma -- or, indeed, where it looks like they are about to do so.

 

[Latest Update: 16/05/17.]

 

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(1)   Return Of Lamarck?

 

(i)  Genomes Modified By The Environment

 

(ii) Acquired Characteristics Inherited?

 

(2)   Is Everything We Know About The Universe False?

 

(3)   Plate Tectonics On The Slide?

 

(4)   Heisenberg For The High Jump?

 

(5)   Quantum Mechanics -- Probably Defective?

 

(i)  Mathematical Foundations Shaky

 

(ii) Probability "As Useful To Physics As Flat-Earth Theory"

 

(6)    Is It Higgs Or Not? Does It Even Matter?

 

(7)    Supersymmetry Bites The Dust?

 

(8)    Neuroscience -- Having A Nervous Breakdown?

 

(9)    Is Much Of Science Wrong?

 

(10)  Saturated Fats Might Not Be Bad For You After All

 

(11)  Gravitational Waves Discovered? Yes! Er..., Oops..., No!

 

(12)  Time To Wave 'Goodbye' To 'Dark Matter'?

 

(13)  The Periodic Table -- About To Decay?

 

(14)  Should We Ditch The Current Theory Of The Solar System?

 

(15)  Cosmological Principle Ready For The Scrapheap?

 

(16)  Cosmic Expansion In Crisis?

 

Summary Of My Main Objections To Dialectical Materialism

 

Abbreviations Used At This Site

 

Return To The Main Index Page

 

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[Latest Update:  ]

 

Lamarck Makes A Comeback

 

Genome Modified By The Environment

 

For over a hundred years we had been told that the environment can't alter the genome, and that anyone who accepted Lamarckism was branded as some sort of heretic, but now we find out that maybe Lamarck was right:

 

"Conditions in the uterus can give rise to life-long changes in genetic material. People in their sixties who were conceived during the Hunger Winter of 1944-45 in the Netherlands have been found to have a different molecular setting for a gene which influences growth. Researchers from the LUMC are the first to demonstrate this effect. They published their findings this week in PNAS Online Early Edition, together with colleagues from Columbia University.

 

"During the Hunger Winter (the Dutch famine of 1944-1945) the west of the Netherlands suffered from an extreme lack of food. It now appears that the limited food intake of mothers who were pregnant during this period altered the genetic material of embryos in the early stages of development. The effects of this can still be observed some sixty years later. These alterations are not changes in the genetic code, but a different setting for the code which indicates whether a gene is on or off. This is known as epigenetics. One of the main processes in epigenetics is connecting the small molecule methyl to DNA.

 

"The researchers compared the degree of methylation of a piece of DNA, the IGF2 gene, of people who were conceived in the Hunger Winter with that of their brothers and sisters. They chose this particular gene because it plays an important role during gestation. People in their sixties who were conceived during the Hunger Winter have less methyl groups on the IGF2 gene than their siblings. This did not apply to children of the Hunger Winter who were in later stages of gestation when the famine occurred. They did have a lower birth weight than their siblings, but the IGF2 gene was not 'packaged' differently. This indicates that epigenetic information is particularly vulnerable in the early stages of pregnancy.

 

"'The next question is whether the epigenetic change which has been identified is a "scar" on the DNA because of lack of food, or a specific adaptation to the shortage of food,' comments Prof Eline Slagboom. Researcher Dr Bas Heijmans: 'Epigenetics could be a mechanism which allows an individual to adapt rapidly to changed circumstances. Changes in the DNA sequence occur by chance and it takes generations before a favourable mutation spreads throughout the population. By then, a temporary famine is long past. It could be that the metabolism of children of the Hunger Winter has been set at a more economical level, driven by epigenetic changes.' This could explain why children of the Hunger Winter suffer more frequently from obesity and cardio-vascular diseases. The research was partly financed by the Netherlands Heart Foundation and the EU network LifeSpan." [Leiden University Report, October 2011. Quotation marks altered to conform with the conventions adopted at this site.]

 

"Epigenetics: Genome, Meet Your Environment


"As the evidence accumulates for epigenetics, researchers reacquire a taste for Lamarckism

 

"Toward the end of World War II, a German-imposed food embargo in western Holland -- a densely populated area already suffering from scarce food supplies, ruined agricultural lands, and the onset of an unusually harsh winter -- led to the death by starvation of some 30,000 people. Detailed birth records collected during that so-called Dutch Hunger Winter have provided scientists with useful data for analyzing the long-term health effects of prenatal exposure to famine. Not only have researchers linked such exposure to a range of developmental and adult disorders, including low birth weight, diabetes, obesity, coronary heart disease, breast and other cancers, but at least one group has also associated exposure with the birth of smaller-than-normal grandchildren. The finding is remarkable because it suggests that a pregnant mother's diet can affect her health in such a way that not only her children but her grandchildren (and possibly great-grandchildren, etc.) inherit the same health problems.

 

"In another study, unrelated to the Hunger Winter, researchers correlated grandparents' prepubertal access to food with diabetes and heart disease. In other words, you are what your grandmother ate. But, wait, wouldn't that imply what every good biologist knows is practically scientific heresy: the Lamarckian inheritance of acquired characteristics?

 

"If agouti mice are any indication, the answer could be yes. The multicoloured rodents make for a fascinating epigenetics story, which Randy Jirtle and Robert Waterland of Duke University told last summer in a Molecular and Cell Biology paper; many of the scientists interviewed for this article still laud and refer to that paper as one of the most exciting recent findings in the field. The Duke researchers showed that diet can dramatically alter heritable phenotypic change in agouti mice, not by changing DNA sequence but by changing the DNA methylation pattern of the mouse genome. 'This is going to be just massive,' Jirtle says, 'because this is where environment interfaces with genomics.'

 

"Epigenetics Explained

 

"This type of inheritance, the transmission of non-DNA sequence information through either meiosis or mitosis, is known as epigenetic inheritance. From the Greek prefix epi, which means 'on' or 'over', epigenetic information modulates gene expression without modifying actual DNA sequence. DNA methylation patterns are the longest-studied and best-understood epigenetic markers, although ethyl, acetyl, phosphoryl, and other modifications of histones, the protein spools around which DNA winds, are another important source of epigenetic regulation. The latter presumably influence gene expression by changing chromatin structure, making it either easier or more difficult for genes to be activated.

 

"Because a genome can pick up or shed a methyl group much more readily than it can change its DNA sequence, Jirtle says epigenetic inheritance provides a 'rapid mechanism by which [an organism] can respond to the environment without having to change its hardware.' Epigenetic patterns are so sensitive to environmental change that, in the case of the agouti mice, they can dramatically and heritably alter a phenotype in a single generation. If you liken the genome to the hardware of a computer, Jirtle explains, then 'epigenetics is the software. It's the grey area. It's just so darn beautiful if you think about it.'

 

"The environmental lability of epigenetic inheritance may not necessarily bring to mind Lamarckian images of giraffes stretching their necks to reach the treetops (and then giving birth to progeny with similarly stretched necks), but it does give researchers reason to reconsider long-refuted notions about the inheritance of acquired characteristics. Eighteenth-century French naturalist Jean Baptiste de Lamarck proposed that environmental cues could cause phenotypic changes transmittable to offspring. 'He had a basically good idea but a bad example,' says Rohl Oflsson, Uppsala University, Sweden.

 

"Although the field of epigenetics as it is known today (that is, the study of heritable changes in gene expression and regulation that have little to do with DNA sequence) has been around for only 20 years or so, the term epigenetics has been in use since at least the early 1940s. Developmental biologist Conrad Waddington used it back then to refer to the study of processes by which genotypes give rise to phenotypes (in contrast to genetics, the study of genotypes). Some reports indicate that the term is even older than Waddington, dating back to the late 1800s. Either way, early use of the term was in reference to developmental phenomena.

 

"In 2001, Joshua Lederberg proposed the use of more semantically, or historically, correct language. But it appears that today's use of the term is here to stay, at least for now, as are its derivatives: epiallele (genes with different degrees of methylation), epigenome (the genome-wide pattern of methyl and other epigenetic markers), epigenetic therapy (drugs that target epigenetic markers), and even epigender (the sexual identity of a genome based on its imprinting pattern).

 

"Terminology aside, biologists have long entertained the notion that certain types of cellular information can be transmitted from one generation to the next, even as DNA sequences stay the same. Bruce Stillman, director of Cold Spring Harbor Laboratory (CSHL), NY, traces much of today's research in epigenetics back to Barbara McClintock's discovery of transposons in maize. Methyl-rich transposable elements, which constitute over 35% of the human genome, are considered a classical model for epigenetic inheritance. Indeed, the epigenetic lability of Jirtle's agouti mice is due to the presence of a transposon at the 5' end of the agouti gene. But only over the past two decades has the evidence become strong enough to convince and attract large numbers of epigenetics researchers. '[Epigenetics] has very deep roots in biology,' says Stillman, 'but the last few years have been just an explosion in understanding.'

 

"Methylation And More

 

"One of the prominent features of DNA methylation is the faithful propagation of its genomic pattern from one cellular or organismal generation to the next. When a methylated DNA sequence replicates, only one strand of the next-generation double helix has all its methyl markers intact; the other strand needs to be remethylated. According to Massachusetts Institute of Technology biologist Rudy Jaenisch, the field of epigenetics took its first major step forward more than two decades ago when, upon discovering DNA methyltransferases (DMTs, the enzymes that bind methyl groups to cytosine nucleotides), researchers finally had a genetic handle on how epigenetic information was passed along. Now, it is generally believed that DMTs bind methyl groups to the naked cytosines based on the methylation template provided by the other strand. This is known as the maintenance methylase theory.

 

"But even a decade ago, says Wolf Reik of the Babraham Institute, Cambridge, UK, 'a lot of epigenetics was phenomenology, and so people looked at it and said, well, this is all very interesting, but what's the molecular mechanism?' Reik points to recent evidence suggesting a critical link between the two main types of epigenetic regulation, DNA methylation and histone modification, as one of the most interesting recent developments in the field. Because of that link, researcher Eric Selker and colleagues at the University of Oregon, Portland, have proposed that there may be more to methylation propagation than maintenance, despite 25 years of evidence. In 2001, Selker and coauthor Hisashi Tamaru showed that dim-5, a gene that encodes a histone H3 Lys-9 methyltransferase, is required for DNA methylation in the filamentous fungus, Neurospora crassa. The histone enzyme is, in turn, influenced by modifications of histone H3. So even though DNA methylation is guided by a DNA methyltransferase encoded by dim-2, it still takes orders from the chromatin.

 

"In a study by CSHL researchers Robert Martienssen, Shiv Grewal, and colleagues, evidence suggests that histone modifications are, in turn, guided by RNA interference (RNAi). Using the fission yeast Schizosaccharomyces pombe, the researchers deleted genes that encode RNAi molecular machinery and observed a loss of histone H3 lys-9 methylation and impaired centromere function. 'This new understanding has created a lot of excitement,' says Stillman....

 

"Lamarckism Revisited

 

"Normally, the fur of agouti mice is yellow, brown, or a calico-like mixture of the two, depending on the number of attached methyl groups. But when Duke University researchers Jirtle and Waterland fed folic acid and other methyl-rich supplements to pregnant mothers, despite the fact that all offspring inherited exactly the same agouti gene (i.e., with no nucleotide differences), mice who received supplements had offspring with mostly brown fur, whereas mice without supplements gave birth to mostly yellow pups with a higher susceptibility to obesity, diabetes, and cancer. The methyl groups bound to a transposon at the 5' end of the agouti locus, thereby shutting off expression of the agouti gene, not just in the murine recipient but in its offspring as well.

 

"Although the study demonstrates that, at least in mice, folic acid supplementation in pregnant mothers reduces the risk of their babies having certain health problems, Jirtle warns that the results cannot be extrapolated to humans. 'Mice are not men,' he emphasizes. But he doesn't downplay the proof of principle. The take-home message is not that folic acid supplements are a good thing. Rather, environmental factors such as nutritional supplementation can have a dramatic impact on inheritance, not by changing the DNA sequence of a gene or via single-nucleotide polymorphism, but by changing the methylation pattern of that gene. 'It's a proof of concept,' says Donata Vercelli, University of Arizona, Tucson. 'That's why it's so important.'

 

"According to Vercelli, the environmental susceptibility of epigenetics probably explains why genetically identical organisms such as twins can have dramatically different phenotypes in different environments. She points to the agouti mice, as well as another recent cluster of studies on a heat shock protein, Hsp90, in Drosophila melanogaster, as 'model systems that have very eloquently demonstrated' the critically important role that epigenetic inheritance plays in this kind of gene-by-environment interaction.

 

"Hsp90 regulates developmental genes during times of stress by releasing previously hidden or buffered phenotypic variation. Douglas Ruden of the University of Alabama, Tuscaloosa, says he noticed some weird fruit fly phenotypes -- things like appendage-like organs sticking out of their eyes -- at about the same time that a paper appeared in Nature connecting Hsp90 activity in Drosophila to genetic variation. In that paper, Suzanne Rutherford and Susan Lindquist, then at the University of Chicago, presented compelling evidence that Hsp90 serves as an 'evolutionary capacitor,' a genetic factor that regulates phenotypic expression by unleashing 'hidden' variation in stressful conditions. Even after restoring normal Hsp90 activity, the new phenotypes responded to ten or more generations of selection. The scientists concluded that, once released, even after normal Hsp90 activity was restored, the previously buffered variation persisted in a heritable manner, generation after generation.

 

"When the Lindquist paper came out, Ruden says he thought, 'Ah, I'm probably seeing the same thing.' He was doing some crosses, 'and I started to see this weird phenotype.' But Ruden and collaborators concluded that their strange eye phenotype was due to something other than, or in addition to, the sudden unleashing of hidden genetic variation. Indeed, the researchers used a strain of flies that had little genetic variation, and yet was still capable of responding to 13 generations of selection even after normal Hsp90 activity was restored. Because of the genomic homogeneity of their flies, combined with observations that mutations encoding chromatin-remodeling proteins induced the same abnormal eye phenotype, the investigators concluded that reduced levels of Hsp90 affected the phenotype by epigenetically altering the chromatin.

 

"Although it is hard to imagine that an appendage-like structure sticking out of the eye would be adaptive in times of stress, Vercelli says that epigenetic change clearly can be environmentally induced in a heritable manner, in this case by alterations to Hsp90. The morphological variations in the eye were probably only the most obvious of many phenotypic differences caused by the chromatin changes.

 

"In a written commentary, evolutionary biologist Massimo Pigliucci said that Ruden's experiment was 'one of the most convincing pieces of evidence that epigenetic variation is far from being a curious nuisance to evolutionary biologists.' Pigluicci doesn't go so far as to say that the heritable changes caused by Hsp90 alterations are Lamarckian, but Ruden does. 'Epigenetics has always been Lamarckian. I really don't think there's any controversy,' he says.

 

"Not that Mendelian genetics is wrong; far from it. The increased understanding of epigenetic change and the recent evidence indicating its role in inheritance and development doesn't give epigenetics greater importance than DNA. Genetics and epigenetics go 'hand in hand,' says Ohlsson. In the case of disease, says Reik, 'there are clearly genetic factors involved, but there are also other factors involved. My suspicion is that it will be a combination of genetic and epigenetic factors, as well as environmental factors, that determine all these diseases.'" [Pray (2004). Quotation marks altered to conform with the conventions adopted at this site. Spelling changed to UK English. Bold emphases and some links added. References included in the original article have been omitted.]

 

On this, see Carey (2011) and Francis (2012). [Details concerning these two books can be accessed here.]

 

Acquired Characteristics Inherited?

 

The New Scientist, January 2015, again:

 

"We used to think evolution had to start with random mutations -- now walking fish and bipedal rats are turning our ideas on their head

 

"'To be honest, I was intrigued to see if they'd even survive on land,' says Emily Standen. Her plan was to drain an aquarium of nearly all the water and see how the fish coped. The fish in question were bichir fish that can breathe air and haul themselves over land when they have to, so it's not as far-fetched as it sounds.

 

"What was perhaps more questionable was Standen's rationale. Two years earlier, in 2006, Tiktaalik had become a global sensation. This 360-million-year-old fossil provides a snapshot of the moment our fishy ancestors hauled themselves out of the water and began trading fins for limbs. Standen thought forcing bichir fish to live almost entirely on land could reveal more about this crucial step in our evolution. Even if you were being kind, you might have described this notion as a little bit fanciful.

 

"Today, it seems positively inspired. The bichirs did far more than just survive. They became better at 'walking'. They planted their fins closer to their bodies, lifted their heads higher off the ground and slipped less than fish raised in water. Even more remarkably, their skeletons changed too. Their 'shoulder' bones lengthened and developed stronger contacts with the fin bones, making the fish better at press-ups. The bone attachments to the skull also weakened, allowing the head to move more. These features are uncannily reminiscent of those that occurred as our four-legged ancestors evolved from Tiktaalik-like forebears.

 

"What is really amazing about this experiment is that these changes did not come about after raising generations of fish on land and allowing only the best walkers to breed. Instead, it happened within the lifetime of individual fish. Simply forcing young fish to live on land for eight months was all it took to produce these quite dramatic changes. We have long known that our muscles, sinews and bones adapt to cope with whatever we make them do. A growing number of biologists think this kind of plasticity may also play a key role in evolution. Instead of mutating first and adapting later, they argue, animals often adapt first and mutate later. Experiments like Standen's suggest this process could even play a role in major evolutionary transitions such as fish taking to land and apes starting to walk upright.

 

"The idea that plasticity plays a role in evolution goes back more than a century. Some early biologists thought that characteristics acquired during an animal's lifetime could be inherited by their offspring: giraffes got their long necks by stretching to eat leaves, and so on. The French naturalist Jean-Baptiste Lamarck is the best-known advocate of this idea, but Darwin believed something similar. He even proposed an elaborate mechanism to explain how information about changes in the body could reach eggs and sperm, and therefore be passed on to offspring. In this way, Darwin suggested, plasticity produces the heritable variations on which natural selection can work its magic.

 

"With the rise of modern genetics, such notions were dismissed. It became clear that there is no way for information about what animals do during their lifetime to be passed on to their offspring (although a few exceptions have emerged since). And it was thought this meant plasticity has no role in evolution. Instead, the focus shifted to mutations. By the 1940s, the standard thinking was that animals mutate first and adapt later. A mutation in a sperm cell, say, might produce a physical change in the bodies of some offspring. If the change is beneficial, the mutation will spread through the population. In other words, random genetic mutations generate the variation on which natural selection acts. This remains the dominant view of evolution today.

 

"The dramatic effects of plasticity were not entirely ignored. In the 1940s, for instance, the Dutch zoologist Everhard Johannes Slijper studied a goat that had been born without forelegs and learned to hop around, kangaroo-like, on its rear legs. [It seems that a dog in the UK can do likewise -- RL.] When Slijper examined the goat after its death, he discovered that the shape of its muscles and skeleton looked more like those of a biped than a quadruped. Few biologists considered such findings relevant to the evolutionary process. The fact that changes acquired during an animal's lifetime are transient seemed to rule out that possibility. If Standen's better-at-walking fish were bred and the offspring raised in a normal aquarium, for instance, they should look and behave like perfectly ordinary bichirs.

 

"Transient response

 

"But what if the environmental conditions that induce the plastic response are themselves permanent? In the wild, this could happen as a result of alterations in prey animals, or in the climate, for instance. Then all the members of a population would develop in the same, consistent way down the generations. It would look as if the population had evolved in response to an altered environment, but technically it's not evolution because there is no heritable change. The thing is, the only way to tell would be to 'test' individuals by raising them in different circumstances.

 

"In this way at least, plasticity can allow animals to 'evolve' without evolving. The crucial question, of course, is whether it can lead to actual evolution, in the sense of heritable changes. 'You can plastically induce generation after generation,' says Standen, who is now at the University of Ottawa in Ontario, Canada. 'At some point, can you remove the environmental conditions that induced the change and have the organisms remain changed?' The answer, surprisingly, seems to be yes. In the 1950s, British biologist Conrad Hal Waddington showed that it is feasible in an experiment involving fruit flies. Waddington found that when pupa are briefly heated, some offspring develop without crossveins in their wings. He then selected and bred those flies. By the 14th generation, some lacked crossveins even when their pupa were not heated. A physical feature that began as a plastic response to an environmental trigger had become a hereditary feature.

 

"How is this possible? Plastic changes occur because an environmental trigger affects a developmental pathway in some way. More of a certain hormone may be produced, or produced at a different time, or genes are switched on that normally remain inactive, and so on. The thing is, random mutations can also have similar effects. So in an environment in which a particular plastic response is crucial for survival, only mutations that reinforce this response, or at least do not impede it, can spread through a population. Eventually, the altered developmental pathway will become so firmly stabilised by a genetic scaffolding that it will occur even without the environmental trigger, making it a permanent hereditary feature.

 

"Waddington called this process genetic assimilation. It may sound like Lamarckism, but it is not. The acquired characteristics don't shape the genetic changes directly as Darwin proposed, they merely allow animals to thrive in environments that favour certain mutations when they occur by chance (see diagram). Waddington's findings have been regarded as a curiosity rather than a crucial insight. But in the past decade or two, attitudes have begun to change. One reason for this is a growing appreciation of the flexibility of genes. Rather than being rigidly pre-programmed, we now know that the environment influences many aspects of animals' bodies and behaviour.

 

"Such discoveries have led some biologists to claim that developmental plasticity plays a major role in evolution. A few, such as Kevin Laland at the University of St Andrews, UK, even argue that the conventional 'mutate first, adapt later' picture of evolution needs a rethink (Nature, vol 514, p.161). Most biologists have yet to be convinced. The sceptics point out that genetic assimilation does not overturn any fundamental principles of evolution -- in the long run, evolution is all about the spread of mutations, whether or not plasticity is involved. Yes, say the proponents of plasticity, but the key point is that plasticity can determine which mutations spread (New Scientist, 12 October 2013, p 33), so its role should be given the prominence it deserves. 'Several major recent evolutionary textbooks do not even mention plasticity,' says Laland.

 

"It may play a role occasionally, respond the sceptics, but it's a minor one at best. 'There is little debate that genetic assimilation can happen,' says Gregory Wray of Duke University in Durham, North Carolina. 'But there is unfortunately very little support for its role in nature.' This is what makes Standen's work on the bichir so significant. It implicates plasticity in a major evolutionary transition: fish turning into four-legged land animals (Nature, vol 513, p.54). Plasticity will soon be implicated in another major transition too -- the one our ancestors made from four legs to two about 7 million years ago. As part of his PhD dissertation, Adam Foster, now at the Northeast Ohio Medical University in Rootstown, has been making rats walk on a treadmill. 'I had a custom harness system built so I could modify the load experienced by the hind limbs,' he says. Some rats had to walk on their hind limbs, while others walked on all fours. Each rat exercised on the treadmill for an hour a day for three months, and then Foster examined their skeletons.

 

"He found that the 'bipedal' rats had developed longer legs than standard quadrupedal rats, and that their thigh bones had larger femoral heads -- the ball in the hip joint. Both features are associated with the transition to bipedalism in our hominin ancestors. Foster hopes to publish the results later this year. 'I think Adam's research is really compelling,' says Jesse Young, an anatomist at Northeast Ohio Medical University. 'As he was getting it going, I was a bit sceptical. You couldn't predict it would reveal anything useful.' While the work of Standen and Foster suggests that developmental plasticity could play a role in major evolutionary transitions, it is only suggestive. Indeed, these studies do not even show that the plastic changes seen in the bichir fish and rats can be fixed by mutations. Demonstrating this kind of genetic assimilation would certainly be tricky, says Standen. It would not be practical with the bichir fish she studied. 'As wonderful as they are, they're frustrating fish,' says Standen. 'They take the better part of a decade to mature, and even then they're really difficult to breed in captivity.'

 

"The fossil record is usually no help either. It is possible that some of the changes seen as fish colonised the land were a result of plasticity rather than genetics, says Per Ahlberg of the University of Uppsala in Sweden who studies the transition to land. For Ahlberg, the trouble is that there is no way to prove it. 'There's no evidence that will allow us to choose between the two,' he says.

 

"More evolvable

 

"Other biologists are more enthusiastic. It has long been suggested that different parts of the skeleton are more plastic and 'evolvable' than others, says William Harcourt-Smith of the American Museum of Natural History. 'So a foot bone or a hand bone might give you more useful info than a hip bone, for instance.' Work like Foster's could reveal if this is indeed the case and help us interpret the fossil record of human evolution. 'These experiments do have validity,' Harcourt-Smith says. 'They can help us understand whether traits are plastic or not.'

 

Take the honeycomb structure in the heads of our long bones. It is lighter and weaker than it was in our extinct cousins such as the Neanderthals. A study out last month compared the bones of hunter-gatherers and early farmers in North America. It concluded that our bones became weak only when our ancestors' lifestyles changed (PNAS, doi.org/xwq). 'We could have a skeleton as strong as our prehistoric ancestors,' says team member Colin Shaw of the University of Cambridge, UK. 'We just don't because we're not as active.' It's possible that similar kinds of skeletal structural change seen in prehistory have been misinterpreted as signs of speciation when they really just reflect developmental plasticity, says Shaw -- perhaps especially so in hominin evolution. Humans are unique, he points out. 'Our first line of defence against environmental insult is culture. When that's not adequate -- for instance if the clothing you can make is not good enough to keep you warm -- then arguably the second line of defence is plasticity. Only after that fails might you actually get genetic selection.'

 

"All this still leaves open the question of whether genetic assimilation can 'fix' traits that first appear as a result of plasticity. A decade ago, Richard Palmer at the University of Alberta in Edmonton, Canada, found a way to search for evidence in the fossil record. Most animals have some asymmetric traits. In our case, it's the position of the heart and other organs, which is encoded in our genes. But in other species, asymmetries are plastic. For instance, the enlarged claw of male fiddler crabs...is as likely to be on the left as on the right. What Palmer showed by examining the fossil record of asymmetry in 68 plant and animal species is that on 28 occasions, asymmetries that are now hereditary and appear only on one side started out as non-hereditary asymmetries that appeared on either side (Science, vol 306, p.828). 'I think it's one of the clearest demonstrations that genetic assimilation has happened and that it is more common than expected,' says Palmer.

 

"There is a caveat here, though. The ancestral non-hereditary asymmetries may have been a result of random genetic noise, says Palmer. So while his work does show genetic assimilation in action, it was not necessarily fixing traits due to developmental plasticity. There is no simple way to prove the evolutionary importance of developmental plasticity, says Mary Jane West-Eberhard of the Smithsonian Tropical Research Institute in Costa Rica, whose work has been particularly influential. 'Evolutionary biology that is concerned with evolution and speciation in nature necessarily depends on indirect proof -- an accumulation of facts that support or deny a hypothesis,' she says. At the moment, the facts that are accumulating seem to support the hypothesis. Expect lots more results soon: Standen's success is inspiring others. 'I've already had people ask me what other critters we could try this on,' says Standen. 'Everybody is friendly and excited and interested. It's fun -- it's the way science should be.'" [Barras (2015), pp.26-30. (This links to a PDF.) Quotation marks altered to conform with the conventions adopted at this site. Some links added, and several paragraphs merged to save space.]

 

August 2015: We now read this from The Guardian:

 

"Study of Holocaust survivors finds trauma passed on to children's genes

"Helen Thomson, The Guardian, 21/08/2015

"New finding is first example in humans of the theory of epigenetic inheritance: the idea that environmental factors can affect the genes of your children

"Genetic changes stemming from the trauma suffered by Holocaust survivors are capable of being passed on to their children, the clearest sign yet that one person’s life experience can affect subsequent generations. The conclusion from a research team at New York's Mount Sinai hospital led by Rachel Yehuda stems from the genetic study of 32 Jewish men and women who had either been interned in a Nazi concentration camp, witnessed or experienced torture or who had had to hide during the second world war. They also analysed the genes of their children, who are known to have increased likelihood of stress disorders, and compared the results with Jewish families who were living outside of Europe during the war. 'The gene changes in the children could only be attributed to Holocaust exposure in the parents,' said Yehuda.

"Her team's work is the clearest example in humans of the transmission of trauma to a child via what is called 'epigenetic inheritance' -- the idea that environmental influences such as smoking, diet and stress can affect the genes of your children and possibly even grandchildren. The idea is controversial, as scientific convention states that genes contained in DNA are the only way to transmit biological information between generations. However, our genes are modified by the environment all the time, through chemical tags that attach themselves to our DNA, switching genes on and off. Recent studies suggest that some of these tags might somehow be passed through generations, meaning our environment could have and impact on our children's health.

"Other studies have proposed a more tentative connection between one generation's experience and the next. For example, girls born to Dutch women who were pregnant during a severe famine at the end of the second world war had an above-average risk of developing schizophrenia. Likewise, another study has showed that men who smoked before puberty fathered heavier sons than those who smoked after. The team were specifically interested in one region of a gene associated with the regulation of stress hormones, which is known to be affected by trauma. 'It makes sense to look at this gene,' said Yehuda. 'If there's a transmitted effect of trauma, it would be in a stress-related gene that shapes the way we cope with our environment.'

"They found epigenetic tags on the very same part of this gene in both the Holocaust survivors and their offspring, the same correlation was not found in any of the control group and their children. Through further genetic analysis, the team ruled out the possibility that the epigenetic changes were a result of trauma that the children had experienced themselves.

"'To our knowledge, this provides the first demonstration of transmission of pre-conception stress effects resulting in epigenetic changes in both the exposed parents and their offspring in humans,' said Yehuda, whose work was published in Biological Psychiatry.

"It's still not clear how these tags might be passed from parent to child. Genetic information in sperm and eggs is not supposed to be affected by the environment - any epigenetic tags on DNA had been thought to be wiped clean soon after fertilisation occurs. However, research by Azim Surani at Cambridge University and colleagues, has recently shown that some epigenetic tags escape the cleaning process at fertilisation, slipping through the net. It's not clear whether the gene changes found in the study would permanently affect the children's health, nor do the results upend any of our theories of evolution.

"Whether the gene in question is switched on or off could have a tremendous impact on how much stress hormone is made and how we cope with stress, said Yehuda. 'It's a lot to wrap our heads around. It's certainly an opportunity to learn a lot of important things about how we adapt to our environment and how we might pass on environmental resilience.' The impact of Holocaust survival on the next generation has been investigated for years -- the challenge has been to show intergenerational effects are not just transmitted by social influences from the parents or regular genetic inheritance, said Marcus Pembrey, emeritus professor of paediatric genetics at University College London.

"'Yehuda's paper makes some useful progress. What we're getting here is the very beginnings of a understanding of how one generation responds to the experiences of the previous generation. It's fine-tuning the way your genes respond to the world.'

"Can you inherit a memory of trauma?

"Researchers have already shown that certain fears might be inherited through generations, at least in animals. Scientists at Emory University in Atlanta trained male mice to fear the smell of cherry blossom by pairing the smell with a small electric shock. Eventually the mice shuddered at the smell even when it was delivered on its own. Despite never having encountered the smell of cherry blossom, the offspring of these mice had the same fearful response to the smell -- shuddering when they came in contact with it. So too did some of their own offspring.

"On the other hand, offspring of mice that had been conditioned to fear another smell, or mice who'd had no such conditioning had no fear of cherry blossom. The fearful mice produced sperm which had fewer epigenetic tags on the gene responsible for producing receptors that sense cherry blossom. The pups themselves had an increased number of cherry blossom smell receptors in their brain, although how this led to them associating the smell with fear is still a mystery." [Quoted from here; accessed 22/08/2015. Several paragraphs merged to save space. Quotation marks altered to conform with the conventions adopted at this site. Links in the original. Bold added.]

 

However, it should be noted that there are serious problems with the above research; on that, see here.
 

Is Everything We Know About The Universe Wrong?

 

In 2010, we read this from the BBC:

 

"Is Everything We Know About The Universe Wrong?

 

"There's something very odd going on in space -- something that shouldn't be possible. It is as though vast swathes of the universe are being hoovered up by a vast and unseen celestial vacuum cleaner.

 

"Sasha Kaslinsky, the scientist who discovered the phenomenon, is understandably nervous: 'It left us quite unsettled and jittery' he says, 'because this is not something we planned to find'. The accidental discovery of what is ominously being called 'dark flow' not only has implications for the destinies of large numbers of galaxies -- it also means that large numbers of scientists might have to find a new way of understanding the universe.

 

"Dark flow is the latest in a long line of phenomena that have threatened to rewrite the textbooks. Does it herald a new era of understanding, or does it simply mean that everything we know about the universe is wrong?" [Quoted from here. Bold emphases added.]

 

"14 billion years ago there was nothing; then everything exploded into existence and the universe was born, but a new generation of cosmologists are questioning this theory. Cosmologists have created a replica of the universe by using equations; it's called the standard model of cosmology and it's the reason behind the Big Bang theory; however, this model is now doubted. Professor Alan Guth's theory challenges the Big Bang by stating that the universe started out small, allowing the temperature to even out everywhere, before expanding on a massive scale.

 

"Stars nearer the edge of a galaxy move just as fast as those in the centre. This made cosmologists think that galaxies needed more gravity, but the only way to get more gravity was to create it. Astrophysicist Dan Bauer is hunting for dark matter half a mile under the dark plains of Minnesota in order to trace and record it more effectively. The discovery that the universe is speeding up suggests that a new force is powering the universe. This force is known as dark energy, and cosmologists have no idea what it is.

 

"The combination of the standard model, inflation and dark matter has given way to a new theory called dark flow. The nature of this theory could show that our universe isn't the only one. The standard model of cosmology has withstood much criticism, therefore making the theory stronger; however it could still be totally wrong." [Quoted from here, where the BBC programme in question can be accessed. Bold emphases and links added.]

 

Plate Tectonics On The Slide?

 

August 2012: The New Scientist has yet more disconcerting news to offer its readers:

 

"Plate tectonics can't explain all the earthquakes, volcanoes and landscapes of Earth, so what else is shaping its surface?

 

"'A lot of people (sic) thinks that the devil has come here. Some thinks (sic) that this is the beginning of the world coming to a end.'

 

"To George Heinrich Crist, who wrote this on 23 January 1812, the series of earthquakes that had just ripped through the Mississippi river valley were as inexplicable as they were deadly. Two centuries on and we are no closer to an understanding. According to our established theory of Earth's tectonic activity, the US Midwest is just not the sort of place such tremors should occur.

 

"That's not the only thing we are struggling to explain. Submerged fossil landscapes off the west coast of Scotland, undersea volcanoes in the south Pacific, the bulging dome of land that is the interior of southern Africa: all over the world we see features that plate tectonics alone is hard pressed to describe.

 

"So what can? If a new body of research is to be believed, the full answer lies far deeper in our planet. If so, it could shake up geology as fundamentally as the acceptance of plate tectonics did half a century ago.

 

"The central idea of plate tectonics is that Earth's uppermost layers -- a band of rock between 60 and 250 kilometres thick known as the lithosphere -- is divided into a mosaic of rigid pieces that float and move atop the viscous mantle immediately beneath. The theory surfaced in 1912, when German geophysicist Alfred Wegener argued on the basis of fossil distributions that today's continents formed from a single supercontinent, which came to be called Pangaea, that broke up and began drifting apart 200 million years ago.

 

"Wegener lacked a mechanism to make his plates move, and the idea was at first ridiculed. But evidence slowly mounted that Earth's surface was indeed in flux. In the 1960s people finally came to accept that plate tectonics could not only explain many features of Earth's topography, but also why most of the planet's seismic and volcanic activity is concentrated along particular strips of its surface: the boundaries between plates. At some of these margins plates move apart, creating rift valleys on land or ridges on ocean floors where hotter material wells up from the mantle, cools and forms new crust. Elsewhere, they press up against each other, forcing up mountain chains such as the Himalayas, or dive down beneath each other at seismically vicious subduction zones such as the Sunda trench, the site of the Sumatra-Andaman earthquake in December 2004.

 

"And so plate tectonics became the new orthodoxy. But is it the whole truth? 'Because it was so hugely successful as a theory, everybody became a bit obsessed with horizontal motions and took their eye off an interesting ball,' says geologist Nicky White at the University of Cambridge.

 

"That ball is what is happening deep within Earth, in regions far beyond the reach of standard plate-tectonic theory. The US geophysicist Jason Morgan was a pioneer of plate tectonics, but in the 1970s he was also one of the first to find fault with the theory's explanation for one particular surface feature, the volcanism of the Hawaiian islands. These islands lie thousands of kilometres away from the boundaries of the Pacific plate on which they sit. The plate-tectonic line is that their volcanism is caused by a weakness in the plate that allows hotter material to well up passively from the mantle. Reviving an earlier idea of the Canadian geophysicist John Tuzo Wilson, Morgan suggested instead that a plume of hot mantle material is actively pushing its way up from many thousands of kilometres below and breaking through to the surface.

 

"That went against the flow, and it wasn't until the mid-1980s that others began to think Morgan might have a point. The turnaround came when seismic waves unleashed by earthquakes began to reveal some of our underworld's structure as they travelled through Earth's interior. Seismic waves travel at different velocities through materials of different densities and temperatures. By timing their arrival at sensors positioned on the surface we could begin to construct a 3D view of what sort of material is where....

 

"If we can do that, will history repeat itself, the doubters be won over, and another hotly disputed model become the new orthodoxy? [Professor Dietmar] Müller certainly thinks so: 'Geology is on the cusp of another revolution like plate tectonics.'" [Ananthaswamy (2012), pp.38-41. Italic emphasis in the original; bold emphases added. Quotation marks altered to conform with the conventions adopted at this site. Several links also added.]

 

Heisenberg For The High Jump?

 

September 2012: The BBC reported as follows:

 

"Pioneering experiments have cast doubt on a founding idea of the branch of physics called quantum mechanics. The Heisenberg uncertainty principle is in part an embodiment of the idea that in the quantum world, the mere act of observing an event changes it. But the idea had never been put to the test, and a team writing in Physical Review Letters says 'weak measurements' prove the rule was never quite right. That could play havoc with 'uncrackable codes' of quantum cryptography.

 

"Quantum mechanics has since its very inception raised a great many philosophical and metaphysical debates about the nature of nature itself. Heisenberg's uncertainty principle, as it came to be known later, started as an assertion that when trying to measure one aspect of a particle precisely, say its position, experimenters would necessarily 'blur out' the precision in its speed. That raised the spectre of a physical world whose nature was, beyond some fundamental level, unknowable. This problem with the act of measuring is not confined to the quantum world, explained senior author of the new study, Aephraim Steinberg of the University of Toronto.

 

"'You find a similar thing with all sorts of waves,' he told BBC News. 'A more familiar example is sound: if you've listened to short clips of audio recordings you realise if they get too short you can't figure out what sound someone is making, say between a "p" and a "b". If I really wanted to say as precisely as possible, "when did you make that sound?", I wouldn't also be able to ask what sound it was, I'd need to listen to the whole recording.'

 

"The problem with Heisenberg's theory was that it vastly predated any experimental equipment or approaches that could test it at the quantum level: it had never been proven in the lab. 'Heisenberg had this intuition about the way things ought to be, but he never really proved anything very strict about the value,' said Prof Steinberg. 'Later on, people came up with the mathematical proof of the exact value.'...

 

"Prof Steinberg and his team are no stranger to bending quantum mechanics' rules; in 2011, they carried out a version of a classic experiment on photons -- the smallest indivisible packets of light energy -- that plotted out the ways in which they are both wave and particle, something the rules strictly preclude. This time, they aimed to use so-called weak measurements on pairs of photons, putting into practice an idea first put forward in a 2010 paper in the New Journal of Physics.

 

"Photons can be prepared in pairs which are inextricably tied to one another, in a delicate quantum state called entanglement, and the weak measurement idea is to infer information about them as they pass, before and after carrying out a formal measurement. What the team found was that the act of measuring did not appreciably 'blur out' what could be known about the pairs.

 

"It remains true that there is a fundamental limit of knowability, but it appears that, in this case, just trying to look at nature does not add to that unavoidably hidden world. Or, as the authors put it: 'The quantum world is still full of uncertainty, but at least our attempts to look at it don't have to add as much uncertainty as we used to think!' Whether the finding made much practical difference was an open question, said Prof Steinberg.

 

"'The jury is still out on that. It's certainly more than a footnote in the textbooks; it will certainly change the way I teach quantum mechanics and I think a lot of textbooks. But there's actually a lot of technology that relies on quantum uncertainty now, and the main one is quantum cryptography -- using quantum systems to convey our information securely -- and that mostly boils down to the uncertainty principle.'" [Quoted from here. Minor typos corrected; paragraphs merged to save space. Several links added. Quotation marks altered to conform with the conventions adopted at this site. Italic and bold emphases added.]

 

Quantum Mechanics Defective? -- Probably

 

Mathematical Foundations Shaky

 

September 2012: We encountered this disturbing news in the New Scientist:

 

"What if you constantly change the ingredients in your raw batter, but the baked cake is always lemon? It sounds like something from a surrealist film, but equivalent scenarios seem to play out all the time in the mathematics of the quantum world. Nobel prize-winner Frank Wilczek and colleague Alfred Shapere say we can't ignore the absurdity of the situation any longer. It's time to get to the bottom of what is really going on, and in the process cement our understanding of the fundamental nature of the universe.

 

"They are part of a broader call to arms against those who are content to use the maths behind quantum mechanics without having physical explanations for their more baffling results, a school of thought often dubbed 'shut up and calculate'. 'I don't see why we should take quantum mechanics as sacrosanct,' says Roger Penrose of the University of Oxford. 'I think there's going to be something else which replaces it.'

 

"Einstein's widely accepted theory of special relativity states that nothing can travel faster than the speed of light. But the phenomenon of quantum entanglement seems to flout that speed limit by allowing a measurement of one particle to instantaneously change another, even when the two are widely separated. Einstein famously called this 'spooky action at a distance'. 'It's very disturbing,' says Wilczek of the Massachusetts Institute of Technology. 'It bothered Einstein. It should bother everybody.'

 

"To underline what they mean Wilczek and Shapere of the University of Kentucky in Lexington, examined a quantum system affected by a key aspect of special relativity: simultaneous events might not look simultaneous to all observers. If two fireworks go off at exactly the same time in neighbouring towns, a spectator will be able to see both simultaneously. To an observer moving from one town to the other, one firework will seem to explode first. What holds true for you depends on your frame of reference -- that is, it's relative.

 

"Now add a third firework. If there's a reference frame in which it goes off at the same time as only one of the other two, you'd think there should be another reference frame in which all three happen simultaneously. Surprisingly, that is not how it works mathematically. Instead the calculations only work for 4 of the 6 possible orderings (arxiv.org/abs/1208.3841). The team then applied this test to the quantum world. When particles are entangled, they share a 'wave function'. Physically measuring one of the particles 'collapses' all the possibilities encoded in the wave function into a single value, instantly affecting any entangled partners.

 

"Based on the new maths, if you have three entangled photons and you measure photon A, you can have reference frames where measuring A affects C, or measuring A impacts B, but never where measuring A happens before the effects on both B and C. This implies that measuring photon A can influence events that happened in the past, creating a mathematical paradox. 'That's the tension: how can you have such large effects on the mathematical objects without physical consequences?' Wilczek says...." [New Scientist 22/09/2012, p.13. The on-line article is slightly different from the printed version. Quotation marks altered to conform with the conventions adopted at this site. Several links added. Several paragraphs merged to save space.]

 

 

Probability "As Useful To Physics As Flat-Earth Theory"

 

October 2015: Physicist, David Deutsch had this to say in recent issue of the New Scientist:

 

"Probability is as useful to physics as flat-Earth theory

 

"You can't explain how the world really works with probability. It's time for a different approach

 

"Probability theory is a quaint little piece of mathematics. It is about sets of non-negative numbers that are attached to actual and possible physical events, that sum to 1 and that obey certain rules. It has numerous practical applications. So does the flat-Earth theory: for instance, it's an excellent approximation when laying out your garden.

 

"Science abandoned the misconception that Earth extends over an infinite plane, or has edges, millennia ago. Probability insinuated itself into physics relatively recently, yet the idea that the world actually follows probabilistic rules is even more misleading than saying Earth is flat. Terms such as 'likely', 'probable', 'typical' and 'random', and statements assigning probabilities to physical events are incapable of saying anything about what actually will happen.

 

"We are so familiar with probability statements that we rarely wonder what 'x has a probability of ½' actually asserts about the world. Most physicists think that it means something like: 'If the experiment is repeated infinitely often, half of the time the outcome will be x.' Yet no one repeats an experiment infinitely often. And from that statement about an infinite number of outcomes, nothing follows about any finite number of outcomes. You cannot even define probability statements as being about what will happen in the long run. They only say what will probably happen in the long run.

 

"The awful secret at the heart of probability theory is that physical events either happen or they don't: there's no such thing in nature as probably happening. Probability statements aren't factual assertions at all. The theory of probability as a whole is irretrievably 'normative': it says what ought to happen in certain circumstances and then presents us with a set of instructions. It is normative because it commands that very high probabilities, such as 'the probability of x is near 1', should be treated almost as if they were 'x will happen'. But such a normative rule has no place in a scientific theory, especially not in physics. 'There was a 99 per cent chance of sunny weather yesterday' does not mean 'It was sunny'.

 

"It all began quite innocently. Probability and associated ideas such as randomness didn't originally have any deep scientific purpose. They were invented in the 16th and 17th centuries by people who wanted to win money at games of chance.

 

"Gaming the system

 

"To discover the best strategies for playing such games, they modelled them mathematically. True games of chance are driven by chancy physical processes such as throwing dice or shuffling cards. These have to be unpredictable (having no known pattern) yet equitable (not favouring any player over another). The three-card trick, for example, does not qualify: the conjurer deals the cards unpredictably (to the onlooker) but not equitably. A roulette wheel that indicates each of its numbers in turn, meanwhile, behaves equitably but predictably, so equally cannot be used to play a real game of roulette.

 

"Earth was known to be spherical long before physics could explain how that was possible. Similarly, before game theory, mathematics could not yet accommodate an unpredictable, equitable sequence of numbers, so game theorists had to invent mathematical randomness and probability. They analysed games as if the chancy elements were generated by 'randomisers': abstract devices generating random sequences, with uniform probability. Such sequences are indeed unpredictable and equitable -- but also have other, quite counter-intuitive properties.

 

"For a start, no finite sequence can be truly random. To expect fairly tossed dice to be less likely to come up with a double after a long sequence of doubles is a falsehood known as the gambler's fallacy. But if you know that a finite sequence is equitable -- it has an equal number of 1s and 0s, say -- then towards the end, knowing what came before does make it easier to predict what must come next.

 

"A second objection is that because classical physics is deterministic, no classical mechanism can generate a truly random sequence. So why did game theory work? Why was it able to distinguish useful maxims, such as 'never draw to an inside straight' in poker, from dangerous ones such as the gambler's fallacy? And why, later, did it enable true predictions in countless applications, such as Brownian motion, statistical mechanics and evolutionary theory? We would be surprised if the four of spades appeared in the laws of physics. Yet probability, which has the same provenance as the four of spades but is nonsensical physically, seems to have done just that.

 

"The key is that in all of these applications, randomness is a very large sledgehammer used to crack the egg of modelling fair dice, or Brownian jiggling with no particular pattern, or mutations with no intentional design. The conditions that are required to model these situations are awkward to express mathematically, whereas the condition of randomness is easy, given probability theory. It is unphysical and far too strong, but no matter. One can argue that replacing the dice with a mathematical randomiser would not change the strategy of an ideally rational dice player -- but only if the player assumes that pesky normative rule that a very high probability of something happening should be treated as a statement that it will happen.

 

"So the early game theorists never did quite succeed at finding ways of winning at games of chance: they only found ways of probably winning. They connected those with reality by supposing the normative rule that 'very probably winning' almost equates to 'winning'. But every gambler knows that probably winning alone will not pay the rent. Physically, it can be very unlike actually winning. We must therefore ask what it is about the physical world that nevertheless makes obeying that normative rule rational.

 

"You may have wondered when I mentioned the determinism of classical physics whether quantum theory solves the problem. It does, but not in the way one might expect. Because quantum physics is deterministic too. Indeterminism -- what Einstein called 'God playing dice' -- is an absurdity introduced to deny the implication that quantum theory describes many parallel universes. But it turns out that under deterministic, multi-universe quantum theory, the normative rule follows from ordinary, non-probabilistic normative assumptions such as 'if x is preferable to y, and y to z, then x is preferable to z'.

 

"You could conceive of Earth as being literally flat, as people once did, and that falsehood might never adversely affect you. But it would also be quite capable of destroying our entire species, because it is incompatible with developing technology to avert, say, asteroid strikes. Similarly, conceiving of the world as being literally probabilistic may not prevent you from developing quantum technology. But because the world isn't probabilistic, it could well prevent you from developing a successor to quantum theory. In particular, constructor theory -- the framework that I have advocated for fundamental physics, within which I expect successors to quantum theory to be developed -- is deeply incompatible with physical randomness.

 

"It is easy to accept that probability is part of the world, just as it's easy to imagine Earth as flat when in your garden. But this is no guide to what the world is really like, and what the laws of nature actually are." [Deutsch (2015); quotation marks altered to conform with the conventions adopted at this site. Several paragraphs merged to save space. Emphases in the original.]

 

If this is so, it is hard to see how Bell's Theorem can survive, and with that out goes 'Quantum Entanglement'.

 

Is It Higgs Or Not? Does It Even Matter?

 

November 2012: The New Scientist back-tracked yet again:

 

"So we've finally found it. Or have we? Four months on, the identity of the particle snared at the Large Hadron Collider [LHC -- RL] remains unclear. It may indeed be the much-vaunted Higgs boson. Or it might not. Finding out will require a welter of tests hard to do in the messy environment of the LHC's proton collisions (see 'Particle headache: why the Higgs could spell disaster' -- reproduced below, RL).

 

"What's needed is...wait for it...a successor to the LHC. Physicists have already started dreaming of another huge particle smasher, this time based on electrons, to finally pin down the Higgs. In these straitened times that won't be an easy sell, especially as the LHC still feels so shiny and new. But a successor was always part of the long-term plan and will eventually be needed to make more progress. Whatever the LHC found, the public was captivated. Now is a good time for physicists to start -- subtly -- making their case." [Editorial, New Scientist, 10/11/12, p.3. Several paragraphs merged to save space.]

 

"Particle headache: Why the Higgs could spell disaster

 

"Matthew Chalmers

 

"If the particle discovered at CERN this July is all we think it is, there are good reasons to want it to be something else.

 

"So Peter Higgs didn't get this year's Nobel for physics after all. It would have been the Hollywood ending to a story that began half a century ago with a few squiggles in his notebook, and climaxed on 4 July this year with a tear in his eye as physicists armed with a $6 billion particle collider announced they had found the particle that bears his name. Or something very like it anyway. Higgs wasn't the only one feeling a little emotional. This was the big one, after all. The Higgs boson completes the grand edifice that is the 'standard model' of matter and its fundamental interactions. Job done.

 

"If only things were that simple. As particle physicists gather in Kyoto, Japan, next week for their first big conference since July's announcement, they are still asking whether that particle truly is the pièce de résistance of the standard model. And meanwhile, even more subversive thoughts are doing the rounds: if it is, do we even want it?

 

"Higgs's squiggles aimed to solve a rather abstruse problem. Back in the early 1960s, physicists were flushed with their ability to describe electromagnetic fields and forces through the exchange of massless photons. They desperately wanted a similar quantum theory for the weak nuclear force, but rapidly hit a problem: the calculations demanded that the particles that transmit this force, now known as the W and Z bosons, should be massless too. In reality, they weigh in at around 80 and 90 gigaelectronvolts (GeV), almost 100 times meatier than a proton. The solution hit upon by Higgs and others was a new field that filled space, giving the vacuum a positive energy that in turn could imbue particles with different amounts of mass, according to how much they interacted with it. The quantum particle of this field was the Higgs boson.

 

"As the standard model gradually took shape, it became clear how vital it was to find this particle. The model demanded that in the very early hot universe the electromagnetic and weak nuclear forces were one. It was only when the Higgs field emerged a billionth of a second or less after the big bang that the pair split, in a cataclysmic transition known as electroweak symmetry breaking. The W and Z bosons grew fat and retreated to subatomic confines; the photon, meanwhile, raced away mass-free and the electromagnetic force gained its current infinite range. At the same time, the fundamental particles that make up matter -- things such as electrons and quarks, collectively known as fermions -- interacted with the Higgs field and acquired their mass too. An ordered universe with a set hierarchy of masses emerged from a madhouse of masslessness.

 

"It's a nice story, but one that some find a little contrived. 'The minimal standard model Higgs is like a fairy tale,' says Guido Altarelli of CERN near Geneva, Switzerland. 'It is a toy model to make the theory match the data, a crutch to allow the standard model to walk a bit further until something better comes along.' His problem is that the standard model is manifestly incomplete. It predicts the outcome of experiments involving normal particles to accuracies of several decimal places, but is frustratingly mute on gravity, dark matter and other components of the cosmos we know or suspect to exist. What we need, say Altarelli and others, is not a standard Higgs at all, but something subtly or radically different -- a key to a deeper theory.

 

"Questions of identity

 

"Yet so far, the Higgs boson seems frustratingly plain and simple. The particle born on 4 July was discovered by sifting through the debris of trillions of collisions between protons within the mighty ATLAS and CMS detectors at CERN's Large Hadron Collider. For a start, it was spotted decaying into W and Z bosons, exactly what you would expect from a particle bestowing them with mass. Even so, a definitive ID depends on fiddly measurements of the particle's quantum properties (see 'Reflections on spin'). 'The task facing us now is ten times harder than making the discovery was,' says Dave Newbold of the University of Bristol, UK, a member of the CMS collaboration.

 

"Beyond that, a standard-model Higgs has to decay not just into force-transmitting bosons, but also to matter-making fermions. Here the waters are little muddier. The particle was also seen decaying into two photons, which is indirect proof that it interacts with the heaviest sort of quark, the top quark: according to the theory, the Higgs cannot interact directly with photons because it has no electric charge, so it first splits into a pair of top quarks and antiquarks that in turn radiate photons. Further tentative evidence for fermion interactions comes from the US, where researchers on the now-defunct Tevatron collider at Fermilab in Batavia, Illinois, have seen a hint of the particle decaying into bottom quarks.

 

"But equally, the CMS detector has measured a shortfall of decays into tau leptons, a heavier cousin of the electron. If substantiated, that could begin to conflict with standard model predictions; ATLAS is expected to present its first tau-decay measurements in Kyoto next week. Both ATLAS and CMS see more decays into photons than expected, perhaps signalling the influence of new processes and particles beyond the standard model.

 

"It is too early to draw any firm conclusions. Because we know the new particle's mass fairly well -- it is about 125 GeV, or 223 billionths of a billionth of a microgram -- we can pin down the rates at which it should decay into various particles to a precision of about 1 per cent, if it is the standard Higgs. Because of the limited number of decays seen so far, however, the measurement uncertainty on the new particle's decay rates is more like 20 or even 30 per cent. By the end of the year, ATLAS and CMS will have around two and a half times the data used for the July announcement, but that still won't reduce the uncertainty enough. Then the LHC will be shut down for up to two years to be refitted to collide protons at higher energies. 'We're probably not going to learn significantly more about the new particle in the immediate future,' says Newbold.

 

"What physicists would like to fill this vacuum is a new collider altogether. The LHC is not exactly ideal anyway: it smashes protons together, and protons are sacks of quarks and other innards that make measurements a messy business. Researchers are lobbying for a cleaner electron-positron collider, possibly in Japan, to close the Higgs file, but that too is a distant prospect. So we are left with a particle that looks like the standard Higgs, but we can't quite prove it. And that leaves us facing an elephant in the accelerator tunnel: if it is the standard Higgs, how can it even be there in the first place?

 

"The problem lies in the prediction of quantum theory, confirmed by experiments at CERN's previous mega-accelerator, the Large Electron Positron collider, that particles spontaneously absorb and emit 'virtual' particles by borrowing energy from the vacuum. Because the Higgs boson itself gathers mass from everything it touches, these processes should make its mass balloon from the region of 100 GeV to 1019 GeV. At this point, dubbed the Planck scale, the fundamental forces go berserk and gravity -- the comparative weakling of them all -- becomes as strong as all the others. The consequence is a high-stress universe filled with black holes and oddly warped space-time.

 

"Conspirators sought

 

"One way to avert this disaster is to set the strength of virtual-particle fluctuations that cause the problem so they all cancel out, reining in the Higgs mass and making a universe more like the one we see. The only way to do that while retaining a semblance of theoretical dignity, says Altarelli, is to invoke a conspiracy brought about by a suitable new symmetry of nature. 'But where you have a conspiracy you must have conspirators.'

 

"At the moment, most physicists see those conspirators in the hypothetical superpartners, or 'sparticles', predicted by the theory of supersymmetry. One of these sparticles would partner each standard model particle, with the fluctuations of the partners neatly cancelling each other out. These sparticles must be very heavy: the LHC has joined the ranks of earlier particle smashers in ruling them out below a certain mass, currently around 10 times that of the putative Higgs.

 

"That has already put severe pressure on even the simplest supersymmetric models. But all is not lost, according to James Wells of CERN's theory group. If you don't find sparticles with low masses, you can twiddle the theory, to an extent, and 'dial them up' to appear at higher masses. 'We expected that the Higgs would be found and that a supporting cast would be found with it, but not necessarily at the same energy scale,' he says. [Tweaking the 'epicycles'? -- RL.]

 

"Even so, the goalposts cannot be shifted too far: if the sparticles get too heavy, they won't stabilise the Higgs mass in a convincingly 'natural' way. Sparticles are also hotly sought after as candidates to make up the universe's missing dark matter. Updates will be presented in Kyoto next week, and there is also hope for indirect leads to supersymmetry from measurements of anomalies in the decay rates of other standard-model particles. If nothing stirs there, all eyes are on what happens when the LHC roars back early in 2015 at near double its current collision energy. A revamped LHC should be able to conjure more massive sparticles from thin air, or perhaps even more radical particles such as those associated with extra dimensions of space. These particles amount to another attempt to fill the gap between where the Higgs 'should be' -- at the Planck scale --- and where it actually is.

 

"The weirdest scenario of them all, though, is if there is nothing but tumbleweed between the energies in which the standard model holds firm and those of the Planck scale, where quantum field theories and Einstein's gravity break down. How then would we explain the vast discrepancy between the Higgs's actual mass and that predicted by quantum theory?

 

"Teetering on the brink

 

"One solution is to just accept it: if things were not that way, the masses of all the particles and their interactions strengths would be very different, matter as we know it would not exist, and we would not be here to worry about such questions. Such anthropic reasoning, which uses our existence to exclude certain properties of the universe that might have been possible, is often linked with the concept of a multiverse -- the idea that there are innumerable universes out there where all the other possible physics goes on. To many physicists, it is a cop-out. 'It looks as if it's an excuse to give up on deeper explanations of the world, and we don't want to give up,' says Jon Butterworth of University College London, who works on the ATLAS experiment.

 

"But a second fact about the new particle gives renewed pause for thought. Not only is its 125 GeV mass vastly less than it should be, it is also about as small as it can possibly be without dragging the universe into another catastrophic transition. If it were just a few GeV lighter, the strength of the Higgs interactions would change in such a way that the lowest energy state of the vacuum would dip below zero. The universe could then at some surprise moment 'tunnel' into this bizarre state, again instantly changing the entire configuration of the particles and forces and obliterating structures such as atoms.

 

"As things stand, the universe is seemingly teetering on the cusp of eternal stability and total ruin. 'It's an interesting coincidence that we are right on the border between these two phases,' says CERN theorist Gian Giudice, who set about calculating the implications of a 125 GeV Higgs as soon as the first strong hints came out of the LHC in December last year.

 

"He doesn't know what the answer is. In any case, finding any new particles will change the game once more. 'There are many questions in the history of science whose answers have turned out to be environmental rather than fundamental,' says Giudice. 'The slightest hint of new physics and my calculation will be forgotten.' So that is what all eyes will really be on in Kyoto. Higgs's squiggles seem to have become reality -- but for a more satisfying twist to the tale, we must hope some other squiggles show similar signs of life soon." [New Scientist, 10/11/12, pp.34-37. Several links added. Quotations marks altered to conform with the conventions adopted at this site. The on-line version has a different title to the published article. Bold emphases added. Typo corrected. Several paragraphs merged to save space.]

 

Update November 2014: It looks like the Higgs Boson might not have been discovered, after all; here is what Science News had to say:

 

"Techni-Higgs: European Physicists Cast Doubt on Discovery of Higgs Boson

 

"Nov 10, 2014 by Sci-News.com

 

"'The CERN data are generally taken as evidence that the particle is the Higgs particle. It is true that the Higgs particle can explain the data but there can be other explanations, we would also get these data from other particles,' said Dr Mads Toudal Frandsen of the University of Southern Denmark, the senior author of the study published in the journal Physical Review D (arXiv.org preprint). The study does not debunk the possibility that CERN physicists have discovered the Higgs boson. That is still possible -- but it is equally possible that it is a different kind of particle.

 

"'The current data is not precise enough to determine exactly what the particle is. It could be a number of other known particles,' Dr Frandsen said. 'But if it wasn't the Higgs particle, that was found in CERN's particle accelerator, then what was it? We believe that it may be a so-called techni-Higgs particle. This particle is in some ways similar to the Higgs boson -- hence half of the name.'

 

"Although the techni-Higgs particle and Higgs boson can easily be confused in experiments, they are two very different particles belonging to two very different theories of how the Universe was created. The Higgs particle is the missing piece in the theory called the Standard Model. This theory describes three of the four forces of nature.

 

"'But it does not explain what dark matter is -- the substance that makes up most of the universe. A techni-Higgs particle, if it exists, is a completely different thing,' the scientists said. 'A techni-Higgs particle is not an elementary particle. Instead, it consists of so-called techni-quarks, which we believe are elementary. Techni-quarks may bind together in various ways to form for instance techni-Higgs particles, while other combinations may form dark matter,' Dr Frandsen said.

 

"'We therefore expect to find several different particles at CERN's Large Hadron Collider, all built by techni-quarks.' If techni-quarks exist, there must be a force to bind them together so that they can form particles. None of the four known forces of nature (gravity, the electromagnetic force, the weak nuclear force and the strong nuclear force) are any good at binding techni-quarks together.

 

"'There must therefore be a yet undiscovered force of nature. This force is called the technicolor force. What was found last year in CERN's accelerator could thus be either the Higgs particle of the Standard Model or a light techni-Higgs particle, composed of two techni-quarks.' More data from CERN will probably be able to determine if it was a Higgs or a techni-Higgs particle.

 

"'If CERN gets an even more powerful accelerator, it will in principle be able to observe techni-quarks directly.'" [Taken from here; accessed 11/08/2015. Quotation marks altered to conform with the conventions adopted at this site. Bold emphasis alone added. Several paragraphs merged to save space.]

 

And we also read the following:

 

"God particle may not be God particle: Scientists in shock claim

 

"'Data not precise enough to determine exactly what it is'

 

"A new scholarly paper has raised suspicions in boffinry circles as to whether last year's breakthrough discovery by CERN was indeed the fabled, applecart-busting Higgs boson. The report from the University of Southern Denmark suggests that while physicists working with data from the Large Hadron Collider (LHC) did discover a new particle, the data might not point to the fabled Higgs boson, but rather to a different particle that behaves similarly.

 

"'The CERN data is generally taken as evidence that the particle is the Higgs particle. It is true that the Higgs particle can explain the data but there can be other explanations, we would also get this data from other particles,' said associate professor Mads Toudal Frandsen. 'The current data is not precise enough to determine exactly what the particle is. It could be a number of other known particles.'

 

"The Southern Denmark researchers suggest that the particle discovered by the LHC may not have been the Higgs boson, but rather a 'techni-higgs' particle that's composed of 'techni-quarks.' Such a particle might behave similarly to the Higgs particle but in fact is very different from the genuine Higgs boson. If the researchers are right, their report would discredit the claims of discovery of the Higgs boson, which has been sought because its existence would fill vital holes in the Standard Model of physics.

 

"The researchers claim that although their findings may disprove the Higgs boson discovery, they also pave the way for the discovery of another force -- one not yet uncovered -- that would be responsible for binding the techni-quarks into particles, including those that form dark matter. The group says that more data is needed to establish whether the particle observed by CERN was indeed the Higgs boson or otherwise. One way, they say, would be for CERN to build an even larger collider to better observe the particles and provide more evidence as to the existence of the theorized techni-quarks." [Quoted from here. Accessed 11/08/2015. Links and capitals in the original. Some paragraphs merged to save space; quotation marks altered to conform with the conventions adopted at this site. Bold emphasis added. See also here.]

 

"CERN May Not Have Found The Higgs Boson

Neuroscience -- Experiencing A Nervous Breakdown?

 

October 2013: An editorial from in the New Scientist had this to say:

 

"The idea of putting a dead salmon in a brain scanner would be funny if it were not so serious. When Craig Bennett of the University of California, Santa Barbara, tried it in 2009, he wasn't expecting to find anything -- he was just doing test runs on the machine. But when he looked at the data he got a shock. The fish's brain and spinal column were showing signs of neural activity.

 

"There was no such activity, of course. The salmon was dead. But the signal was there, and it confirmed what many had been quietly muttering for years: there's something fishy about neuroscience.

 

"When fMRI brain scanners were invented in the early 1990s, scientists and the general public were seduced by the idea of watching the brain at work. It seems we got carried away. The field is plagued by false positives and other problems. It is now clear that the majority -- perhaps the vast majority -- of neuroscience findings are as spurious as brain waves in a dead fish (see Hidden depths: Brain science is drowning in uncertainty).

 

"That seems shocking, and not just because neuroscience has appeared to be one of the most productive research areas of recent years. Some of those dodgy findings are starting to make their way into the real world, such as in ongoing debates about the use of fMRI evidence in court.

 

"Some historical perspective is helpful here, however. The problems are not exclusive to neuroscience. In 2005, epidemiologist John Ioannidis published a bombshell of a paper called 'Why most published research findings are false'. In it he catalogued a litany of failures that undermine the reliability of science in general. His analysis concluded that at least half, and possibly a large majority, of published research is wrong.

 

"Ioannidis might have expected anger and denial, but his paper was well received. Scientists welcomed the chance to debate the flaws in their practices and work to put them right.

 

"Things are by no means perfect now. Scientists are under immense pressure to make discoveries, so negative findings often go unreported, experiments are rarely replicated and data is often 'tortured until it confesses'. But -- thanks in no small part to Ioannidis's brutal honesty -- all of those issues are now out in the open and science is working to address them. The kerfuffle over neuroscience is just the latest chapter in a long-running saga." [New Scientist 220, 2939, 18/10/2013, p.3. Accessed 25/10/2013. Links in the original. Quotation marks altered to conform with the conventions adopted at this site.]

 

Add the above to the comments posted in Essay Thirteen Part Three.

 

Is Much Of Science Wrong?

 

October 2013: As the above copy of the New Scientist also noted:

 

"Some historical perspective is helpful here, however. The problems are not exclusive to neuroscience. In 2005, epidemiologist John Ioannidis published a bombshell of a paper called 'Why most published research findings are false'. In it he catalogued a litany of failures that undermine the reliability of science in general. His analysis concluded that at least half, and possibly a large majority, of published research is wrong.

 

"Ioannidis might have expected anger and denial, but his paper was well received. Scientists welcomed the chance to debate the flaws in their practices and work to put them right.

 

"Things are by no means perfect now. Scientists are under immense pressure to make discoveries, so negative findings often go unreported, experiments are rarely replicated and data is often 'tortured until it confesses'. But -- thanks in no small part to Ioannidis's brutal honesty -- all of those issues are now out in the open and science is working to address them. The kerfuffle over neuroscience is just the latest chapter in a long-running saga." [New Scientist 220, 2939, 18/10/2013, p.3. Links in the original. Quotation marks altered to conform with the conventions adopted at this site.]

 

And, here is an article from a few years earlier:

 

"Interview: The man who would prove all studies wrong

 

"When the clinical epidemiologist John Ioannidis published a paper entitled 'Why most published research findings are false' in 2005, he made a lot of scientists very uncomfortable. The study was the result of 15 years' work cataloguing the factors that plague the interpretation of scientific results, such as the misuse of statistics or poor experimental design. Ioannidis tells Jim Giles why his conclusion is not as depressing as it appeared, and what he is doing to improve matters.

 

"You've been described as the 'man who would prove all studies wrong'. What was it like to find yourself in this role?

 

"Overall, the reaction I got was very positive. People should not feel threatened by me: science is an evolutionary process, and contradiction and falsification are part of the game. We have tons of literature and a lot of it will eventually be refuted, but that is not bad news. If a small proportion is correct and survives then we will have progress.

 

"How did you end up taking on the whole of science?

 

"Some of the early work I did looked at whether small studies give the same results as larger ones. After looking at hundreds of studies I started to ask: how often do the results of different studies agree with each other? My conclusion was that sometimes small studies disagreed with large ones beyond the level of chance. Early small studies generally tended to claim more dramatic results than subsequent larger studies. It's not just because scientists often oversell their results; it's also because small studies with negative results are often filed away and never published.

 

"How did you end up taking on the whole of science?

 

"My parents were physicians and I trained in internal medicine. I wanted to deal with people and feel that I could improve their health, but I liked mathematics too. It was difficult for me to choose between the two. Then in 1993, I met Tom Chalmers and Joseph Lau. Tom was one of the first people to run a clinical trial and probably the first physician to combine the results of several studies in a meta-analysis -- he and Joseph described cumulative meta-analysis in 1992. They introduced me to the idea of evidence-based medicine. That meeting had a great influence on me. It showed me how to inject robust quantitative thinking into clinical work.

 

"A lot of your work relies on complex statistical arguments. Can you explain them in simple terms?

 

"In my 2005 paper 'Why most published research findings are false' (PLoS Medicine, vol 2, p.e124), I tried to model the probability of a research finding being true. By research finding I mean any association that is tested empirically. You can make some inferences based on how big the study is, since bigger studies tend to be more reliable. You also need to know what level of statistical significance a researcher is using when they claim a result. There are other things to try and compensate for, such as the fact that researchers seek out positive results to get further funding. These are the layers of complexity I tried to model.

 

"What did your modelling reveal?

 

"For some areas, if you get a positive result then it is 85 per cent or even 90 per cent likely to be true. That is the case for very large-scale randomised clinical trials with very clear protocols, full reporting of results and a long chain of research supporting the finding beforehand. Then there is the other extreme, where an experiment is so poorly designed or so many analyses are performed that a statistically significant finding wouldn't have better than a 1-in-1000 chance of being true.

 

"If most studies are wrong, how can science progress?

 

"Things change as a field matures. In fields that generate data very quickly, you can get one study with an extreme result and then in less than a year you get another with the opposite result. The subsequent research falls somewhere in the middle. I think it works this way because an extreme finding sells in the literature. Once it's published, you get lots of competition in the field. Another group may happen to find something that is extreme in the opposite direction. I don't think it's fraud. We are talking about a sea of analyses. With one click on my computer I can find thousands of results. It's not that difficult for one team to contradict another very quickly.

 

"With so much refutation going on, how can we know what to believe?

 

"By keeping an open mind and trying to be cautious and critical. What's missing from a lot of papers is a sense of whether the result is tentative and unlikely to be true, or whether it has high credibility. This can be really important. For example, we need a lot of certainty about medical care before writing guidelines recommending a certain drug. But in some other fields, research with low credibility is extremely interesting. Most molecular science is highly exploratory and complex, with occasional hints of interesting associations.

 

"How often have you come across high-profile oft-cited papers that later turn out to be wrong?

 

"This is actually a common scenario. Some colleagues and I have looked at high-profile papers, with over 1000 citations each, that were later completely contradicted by large, well-conducted studies. One example is the finding that beta-carotene protects against cancer. It doesn't, but we found a sizeable component of literature where these original beliefs were still supported. It's hard to believe the researchers had never heard they had been refuted.

 

"People aren't willing to abandon their hypothesis. If you spend 20 years on a specific line of thought and suddenly your universe collapses, it is very difficult to change jobs.

 

"How are you trying to improve matters?

 

"I'd like researchers to include credibility estimates in their papers. Many fields rely on a measure of statistical significance called a p-value. The problem is that the same p-value may have very different credibility depending on how the analysis was done and what results preceded it. If you take these into account, you can measure the credibility for a particular finding -- the percentage chance that the largest, most perfect study possible would produce the same outcome. There is uncertainty also in the credibility, but I think we can say what ballpark we are in.

 

"How should we promote the studies that produce more credible results, rather than those that are simply statistically significant?

 

"There are several ways to do this. One: do larger, well-designed studies. Two: instead of having 10 teams of researchers, each working behind closed doors, investigators should collaborate and study the same questions. All the data should be made publicly available. If one team comes up with an interesting result then the whole consortium should try to replicate it. Much of the work I've been doing for the past 10 years has been about creating consortia to carry out research. The experience has been very positive." [New Scientist, 2643, 16/02/2008. pp.44-45. Link and bold emphases in in the original; italic emphases added. Quotation marks altered to conform with the conventions adopted at this site.]

 

[Those confident with the mathematics can consult the original article (from PLOS Magazine), posted here.]

 

Of course, the above interview makes no distinction between a scientific theory and the facts discovered by scientists. Moreover, it also ignores the massive amount of fraud in Medical Science and Pharmacology (and, indeed, the rest of science). [On this, see Angell (2005) and Goldacre (2012), as well as some of the books listed earlier. (Details about these two books can be accessed here).]

 

[The last point is also connected with the content of the next sub-section, where much of the relevant data is heavily controlled by Big Pharma.]

 

Saturated Fats -- Not So Bad After All?

 

March 2014: For generations we were told that saturated fats are harmful, but the picture now appears to be changing.

 

Again, from the BBC:

 

"Saturated fat advice 'unclear'

 

"Swapping butter for a sunflower spread may not lower heart risk, say British Heart Foundation researchers. Contrary to guidance, there is no evidence that changing the type of fat you eat from 'bad' saturated to 'healthier' polyunsaturated cuts heart risk. They looked at data from 72 studies with more than 600,000 participants. Heart experts stressed the findings did not mean it was fine to eat lots of cheese, pies and cakes.

 

"Too much saturated fat can increase the amount of cholesterol in the blood, which can increase the risk of developing coronary heart disease. Saturated fat is the kind of fat found in butter, biscuits, fatty cuts of meat, sausages and bacon, and cheese and cream. Most of us eat too much of it -- men should eat no more than 30g a day and women no more than 20g a day. There has been a big health drive to get more people eating unsaturated fats such as olive and sunflower oils and other non-animal fats -- instead.

 

"But research published in Annals of Internal Medicine, led by investigators at the University of Cambridge, found no evidence to support this. Total saturated fat, whether measured in the diet or in the bloodstream as a biomarker, was not associated with coronary disease risk in the 72 observational studies. And polyunsaturated fat intake did not offer any heart protection.

 

"Trans fats were strongly and positively associated with risk of heart diseases. These artificial fats, found in many processed food items and margarine spreads, should continue to be regulated and avoided, say the study authors. Lead researcher Dr Rajiv Chowdhury said: 'These are interesting results that potentially stimulate new lines of scientific inquiry and encourage careful reappraisal of our current nutritional guidelines.'

 

"He added that the common practice of replacing saturated fats in our diet with excess carbohydrates (such as white bread, white rice, potatoes etc.), or with refined sugar and salts in processed foods should be discouraged. 'Refined carbohydrates, sugar and salt are all potentially harmful for vascular health,' he said. The British Heart Foundation said the findings did not change the advice that eating too much fat is harmful for the heart.

 

"Prof Jeremy Pearson, the charity's associate medical director, said: 'This research is not saying that you can eat as much fat as you like. Too much fat is bad for you. But, sadly, this analysis suggests there isn't enough evidence to say that a diet rich in polyunsaturated fats but low in saturated fats reduces the risk of cardiovascular disease. Alongside taking any necessary medication, the best way to stay heart healthy is to stop smoking, stay active, and ensure our whole diet is healthy -- and this means considering not only the fats in our diet but also our intake of salt, sugar and fruit and vegetables.'" [Quoted from here; accessed 19/03/2014. Quotation marks altered to conform with the conventions adopted at this site; several paragraphs merged to save space. All but one link and emphases added.]

 

Of course, 'maverick' health scientists have been arguing along these lines for years; see, for example, Campbell-McBride (2007). [However, also see here for a different view on Campbell-McBride's work. Details concerning Campbell-McBride's book can be found here.]

 

And then there is this:

 

 

Video One: How Bad Science And Big Business Created The Obesity Epidemic

 

August 2014: The New Scientist poses the following question: "Did we really get 40 years of dietary advice wrong?" The answer, as it turns out, is rather complex:

 

"Heart attack on a plate? The truth about saturated fat

 

"After decades of health warnings, the idea that steak, cheese and lard are bad for your heart is melting away. The truth is more complex -- and delicious

 

"There's a famous scene in Woody Allen's film Sleeper in which two scientists in the year 2173 are discussing the dietary advice of the late 20th century.

 

'You mean there was no deep fat, no steak or cream pies or hot fudge?' asks one, incredulous. 'Those were thought to be unhealthy,' replies the other. 'Precisely the opposite of what we now know to be true.'

 

"We're not quite in Woody Allen territory yet, but steak and cream pies are starting to look a lot less unhealthy than they once did. After 35 years as dietary gospel, the idea that saturated fat is bad for your heart appears to be melting away like a lump of butter in a hot pan. So is it OK to eat more red meat and cheese? Will the current advice to limit saturated fat be overturned? If it is, how did we get it so wrong for so long? The answers matter. According to the World Health Organization, cardiovascular disease is the world's leading cause of death, killing more than 17 million people annually, about a third of all deaths. It predicts that by 2030, 23 million will succumb each year. In the US, an estimated 81 million people are living with cardiovascular disease. The healthcare bill is a small fortune.

 

"The idea that eating saturated fat -- found in high levels in animal products such as meat and dairy -- directly raises the risk of a heart attack has been a mainstay of nutrition science since the 1970s. Instead, we are urged to favour the 'healthy' fats found in vegetable oils and foods such as fish, nuts and seeds. In the US the official guidance for adults is that no more than 30 per cent of total calories should come from fat, and no more than 10 per cent from saturated fat.... UK advice is roughly the same. That is by no means an unattainable target: an average man could eat a whole 12-inch pepperoni pizza and still have room for an ice cream before busting the limit. Nonetheless, adults in the UK and US manage to eat more saturated fat than recommended.

 

"We used to eat even more. From the 1950s to the late 1970s, fat accounted for more than 40 per cent of dietary calories in the UK. It was a similar story in the US. But as warnings began to circulate, people trimmed back on foods such as butter and beef. The food industry responded, filling the shelves with low-fat cookies, cakes and spreads. So the message got through, at least partially. Deaths from heart disease have gone down in Western nations. In the UK in 1961 more than half of all deaths were from coronary heart disease; in 2009 less than a third were. But medical treatment and prevention have improved so dramatically it's impossible to tell what role, if any, changes in diet played. And even though fat consumption has gone down, obesity and its associated diseases have not.

 

"To appreciate how saturated fat in food affects our health we need to understand how it is handled by the body, and how it differs from other types of fat. When you eat fat, it travels to the small intestine where it is broken down into its constituent parts -- fatty acids and glycerol -- and absorbed into cells lining the gut. There they are packaged up with cholesterol and proteins and posted into the bloodstream. These small, spherical packages are called lipoproteins, and they are what allow water-insoluble fats and cholesterol (together known as lipids) to get to where they are needed.

 

"The more fat you eat, the higher the levels of lipoprotein in your blood. And that, according to conventional wisdom, is where the health problems begin. Lipoproteins come in two main types, high density and low density. Low-density lipoproteins (LDLs) are often simply known as 'bad cholesterol' despite the fact that they contain more than just cholesterol. LDLs are bad because they can stick to the insides of artery walls, resulting in deposits called plaques that narrow and harden the vessels, raising the risk that a blood clot could cause a blockage. Of all types of fat in the diet, saturated fats have been shown to raise bad cholesterol levels the most. (Consuming cholesterol has surprisingly little influence: the reason it has a bad name is that it is found in animal foods that also tend to be high in saturated fat.)

 

"High-density lipoproteins (HDLs), or 'good cholesterol', on the other hand, help guard against arterial plaques. Conventional wisdom has it that HDL is raised by eating foods rich in unsaturated fats or soluble fibre such as whole grains, fruits and vegetables. This, in a nutshell, is the lipid hypothesis, possibly the most influential idea in the history of human nutrition.

 

"The hypothesis traces its origins back to the 1940s when a rising tide of heart attacks among middle-aged men was spreading alarm in the US. At the time this was explained as a consequence of ageing. But Ancel Keys, a physiologist at the University of Minnesota, had other ideas. Keys noted that heart attacks were rare in some Mediterranean countries and in Japan, where people ate a diet lower in fat. Convinced that there was a causal link, he launched the pioneering Seven Countries Study in 1958. In all, he recruited 12,763 men aged 40 to 59 in the US, Finland, The Netherlands, Italy, Yugoslavia, Greece and Japan. The participants' diet and heart health were checked five and 10 years after enrolling. Keys concluded that there was a correlation between saturated fat in food, raised levels of blood lipids and the risk of heart attacks and strokes. The lipid hypothesis was born.

 

"The finding was supported by other research, notably the Framingham Heart Study, which tracked diet and heart health in a town in Massachusetts. In light of this research and the rising toll -- by the 1980s nearly a million Americans a year were dying from heart attacks -- health authorities decided to officially push for a reduction in fat, and saturated fat in particular. Official guidelines first appeared in 1980 in the US and 1991 in the UK, and have stood firm ever since. Yet the voices of doubt have been growing for some time. In 2010, scientists pooled the results of 21 studies that had followed 348,000 people for many years. This meta-analysis found 'no significant evidence' in support of the idea that saturated fat raises the risk of heart disease (American Journal of Clinical Nutrition, vol 91, p.535).

 

"The doubters were given a further boost by another meta-analysis published in March (Annals of Internal Medicine, vol 160, p.398). It revisited the results of 72 studies involving 640,000 people in 18 countries. To the surprise of many, it did not find backing for the existing dietary advice. 'Current evidence does not clearly support guidelines that encourage high consumption of polyunsaturated fatty acids and low consumption of total saturated fats,' it concluded. 'Nutritional guidelines...may require reappraisal.'

 

"In essence, the study found that people at the extreme ends of the spectrum -- that is, those who ate the most or least saturated fat -- had the same chance of developing heart disease. High consumption of unsaturated fat seemed to offer no protection. The analysis has been strongly criticised for containing methodological errors and omitting studies that should have been included. But the authors stand by their general conclusions and say the paper has already had the intended effect of breaking the taboo around saturated fat.

 

"Outside of academia, its conclusion was greeted with gusto. Many commentators interpreted it as a green light to resume eating saturated fat. But is it? Did Keys really get it wrong? Or is there some other explanation for the conflict between his work and the many studies that supported it, and the two recent meta-analyses? Even as Keys's research was starting to influence health advice, critics were pointing out flaws in it. One common complaint was that he cherry-picked data to support his hypothesis, ignoring countries such as France which had high-fat diets but low rates of heart disease. The strongest evidence in favour of a low-fat diet came from Crete, but it transpired that Keys had recorded some food intake data there during Lent, a time when Greek people traditionally avoid meat and cheese, so he may have underestimated their normal fat intake.

 

"The Framingham research, too, has its detractors. Critics say that it followed an unrepresentative group of predominantly white men and women who were at high risk for heart disease for non-dietary reasons such as smoking. More recently, it has also become clear that the impact of saturated fat is more complex than was understood back then.

 

"Ronald Krauss of the University of California, San Francisco, has long researched the links between lipoprotein and heart disease. He was involved in the 2010 meta-analysis and is convinced there is room for at least a partial rethink of the lipid hypothesis. He points to studies suggesting that not all LDL is the same, and that casting it all as bad was wrong. It is now widely accepted that LDL comes in two types -- big, fluffy particles and smaller, compact ones. It is the latter, Krauss says, that are strongly linked to heart-disease risk, while the fluffy ones appear a lot less risky. Crucially, Krauss says, eating saturated fat boosts fluffy LDL. What's more, there is some research suggesting small LDL gets a boost from a low-fat, high-carbohydrate diet, especially one rich in sugars.

 

"Why might smaller LDL particles be riskier? In their journey around the bloodstream, LDL particles bind to cells and are pulled out of circulation. Krauss says smaller LDLs don't bind as easily, so remain in the blood for longer -- and the longer they are there, the greater their chance of causing damage. They are also more easily converted into an oxidised form that is considered more damaging. Finally, there are simply more of them for the same overall cholesterol level. And more LDLs equate to greater risk of arterial damage, Krauss says. He thinks that the evidence is strong enough for the health advice to change.

 

"But Susan Jebb, professor of diet and population health at the University of Oxford, says it is too early to buy into this alternative model of LDLs and health. 'The jury has to be out because relatively few of the studies have subdivided LDL. It may well be worth exploring, but right now I am not persuaded.' Jeremy Pearson, a vascular biologist and associate medical director at the British Heart Foundation, which part-funded the 2014 meta-analysis, agrees. He says the original idea that a diet high in saturated fat raises the risk of heart disease remains persuasive, and that there are other meta-analyses that support this. He also points to hard evidence from studies in animals, where dietary control is possible to a degree that it is not in people. They repeatedly show high saturated fat leads to high LDL and hardened arteries, he says.

 

"So how does he explain the meta-analyses that cast doubt on the orthodoxy? 'I guess what that means is that in free living humans there are other things that are usually more important regarding whether you have a heart attack or not than the balance of saturated and unsaturated fat in your diet,' Pearson says. Factors such as lack of exercise, alcohol intake and body weight may simply overshadow the impact of fat.

 

"Certainly, the debate cannot be divorced from the issue of overall calorie intake, which rose in the three decades from the 1970s in the US and many other countries. The result was rising numbers of overweight people. And being overweight or obese raises the risk of heart disease. Another key factor might be what people now eat instead of saturated fat. 'The effect of reducing saturated fat depends on what replaces it,' says Walter Willett of the Harvard School of Public Health. 'We consciously or unconsciously replace a large reduction in calories with something else.' The problem, as some see it, is that the something else is usually refined carbohydrates, especially sugars, added to foods to take the place of fat. A review in 2009 showed that if carbohydrates were raised while saturated fat cut, the outcome was a raised heart-disease risk. This plays to the emerging idea that sugar is the real villain.

 

"Then there are trans fats. Created by food chemists to replace animal fats such as lard, they are made by chemically modifying vegetable oils to make them solid. Because they are unsaturated, and so 'healthy' the food industry piled them into products such as cakes and spreads. But it later turned out that trans fats cause heart disease. All told, it is possible that the meta-analyses simply show that the benefits of switching away from saturated fat were cancelled out by replacing them with sugar and trans fats. Meanwhile, science continues to unravel some intricacies of fat metabolism which could also help to account for the confusing results. One promising avenue is that not all types of saturated fat are the same. The 2014 meta-analysis, for example, found clear indications that different saturated fatty acids in blood are associated with different coronary risk. Some saturated fats appear to lower the risk; some unsaturated ones increase it.

 

"Although further big studies are needed to confirm these findings, lead author Rajiv Chowdhury, an epidemiologist at the University of Cambridge, says this is an avenue that might be worth exploring. There is other evidence that not all saturated fats are the same. A study from 2012 found that while eating lots of saturated fat from meat increased the risk of heart disease, equivalent amounts from dairy actually reduced it. The researchers calculated that cutting calories from meaty saturated fat by just 2 per cent and replacing them with saturated fat from dairy reduces the risk of a heart attack or stroke by 25 per cent.

 

"Krauss also cites studies showing that eating cheese does not raise bad cholesterol as much as eating butter, even when both have identical levels of saturated fat. So could future advice say that saturated fat from dairy sources is less risky than that from meat, for example? Or urge us to favour cheese over butter? It's too early to say. Jebb is aware that the idea that some saturated fatty acids may be worse than others is gaining credence, but says it is far from being ready to guide eating habits.

 

"Nonetheless, there is a growing feeling that we need to reappraise our thinking on fat. Marion Nestle, professor of nutrition at New York University, says that studies of single nutrients have a fundamental flaw. 'People do not eat saturated fat,' she says. 'They eat foods containing fats and oils that are mixtures of saturated, unsaturated and polyunsaturated fats, and many other nutrients that affect health and also vary in calories. So teasing saturated fat out of all that is not simple.'

 

"The only way to rigorously test the various hypotheses would be to put some people on one kind of diet and others on another for 20 years or more. 'Doable? Fundable? I don't think so,' says Nestle. So where does that leave us? Is it time to reverse 35 years of dietary advice and stop worrying about fuzzing up our arteries? Some nutritionists say yes. Krauss advocates a rethink of guidelines on saturated fat when a new version of the Dietary Guidelines for Americans is put together next year. He certainly believes that the even stricter limit on saturated fat recommended by the American Heart Association -- that it constitute no more than 7 per cent of daily calorie intake -- should be relaxed.

 

"Others, though, strike a note of caution. Nestle says that the answer depends on context. 'If calories are balanced and diets contain plenty of vegetables, foods richer in saturated fat should not be a problem. But that's not how most people eat,' she says. Jebb and Pearson see no reason to shift the guidance just yet, although Jebb says it may be time for a review of fat by the UK's Scientific Advisory Committee on Nutrition, which last visited the issue in 1991.

 

"So while dietary libertarians may be gleefully slapping a big fat steak on the griddle and lining up a cream pie with hot fudge for dessert, the dietary advice of the 1970s still stands -- for now. In other words, steak and butter can be part of a healthy diet. Just don't overdo them." [New Scientist 223, 2980, 02/08/2014, pp.32-37. Quotation marks altered to conform with the conventions adopted at this site. Some links and bold emphases added. Several paragraphs merged to save space. The online article has a different title to the published version.]

 

So, in the DM-"Totality", are such such fats harmful or not?

 

October 2015: Hold the press! Here is a letter published in a recent issue of the New Scientist:

 

"Saturated fat is not off the hook

 

"From Neal Barnard, Physicians Committee For Responsible Medicine

 

"You report a new Canadian study on the risks of trans fats and saturated fat (15 August, p.6). This meta-analysis of 41 previous reports looked at the data in two ways. One way revealed the dangers of saturated fat, while the other did not. Neither showed that saturated fat is safe. The first analysis used more or less raw data, finding that people whose diets were heaviest in saturated fat had a 12 per cent higher risk of developing heart disease and a 20 per cent higher risk of dying from it, compared with those whose diets were lowest in saturated fat. Trans fats, found in many snack foods, were also linked to heart disease.

 

"The second looked at data adjusted for cholesterol levels, body weight, and so on. This is statistically risky. For example, saturated fat increases cholesterol levels, which, in turn, increase cardiovascular risk. Adjusting the data for cholesterol levels as if they were an independent variable can make the link between saturated fat and cardiovascular risk disappear. Meta-analyses are like metal detectors. If they find a landmine, you can be confident that it is there. But if they don't find one, that does not mean that it's time to go skipping through the field. It may be that your method is simply not sensitive enough." [Quoted from here. Paragraphs merged to save space.]

 

Until scientists finally make up their minds (if ever!), perhaps we should consign this topic to the 'revolving door' department of the "Totality"...

 

Gravitational Waves Discovered? Yes!..., Er..., Oops!..., Er..., No!

 

March 2014: A story rapidly spread across the entire media that heralded the 'discovery' of gravitational waves -- in fact, it was nicely timed to coincide with the release of Gravity on DVD. According to a BBC Horizon programme -- Aftershock broadcast in March 2015 --, this 'news' "made headlines right around the world". As a result, we witnessed countless mega-hyped reports, rather like the following breathless and uncritical article (which included irresponsible speculation about a Nobel Prize!) in The Guardian:

 

"Gravitational waves: have US scientists heard echoes of the big bang?

 

"There is intense speculation among cosmologists that a US team is on the verge of confirming they have detected 'primordial gravitational waves' -- an echo of the big bang in which the universe came into existence 14bn years ago. Rumours have been rife in the physics community about an announcement due on Monday from the Harvard-Smithsonian Center for Astrophysics. If there is evidence for gravitational waves, it would be a landmark discovery that would change the face of cosmology and particle physics. Gravitational waves are the last untested prediction of Albert Einstein's General Theory of Relativity. They are minuscule ripples in the fabric of the universe that carry energy across space, somewhat similar to waves crossing an ocean. Convincing evidence of their discovery would almost certainly lead to a Nobel prize.

 

"'If they do announce primordial gravitational waves on Monday, I will take a huge amount of convincing,' said Hiranya Peiris, a cosmologist from University College London. 'But if they do have a robust detection…Jesus, wow! I'll be taking next week off.'

 

"The discovery of gravitational waves from the big bang would offer scientists their first glimpse of how the universe was born. The signal is rumoured to have been found by a specialised telescope called Bicep (Background Imaging of Cosmic Extragalactic Polarization) at the south pole. It scans the sky at microwave frequencies, where it picks up the fossil energy from the big bang. For decades, cosmologists have thought that the signature of primordial gravitational waves could be imprinted on this radiation. 'It's been called the Holy Grail of cosmology,' says Peiris, 'It would be a real major, major, major discovery.' Martin Hendry at the University of Glasgow works on several projects designed to directly detect gravitational waves. 'If Bicep have made a detection,' he says, 'it's clear that this new window on the universe is really opening up.'

 

"According to theory, the primordial gravitational waves will tell us about the first, infinitesimal moment of the universe's history. Cosmologists believe that 10-34 seconds after the big bang (a decimal point followed by 33 zeros and a one) the universe was driven to expand hugely. Known as inflation, the theory was dreamed up to explain why the universe is so remarkably uniform from place to place. But it has always lacked some credibility because no one can find a convincing physical explanation for why it happened. Now researchers may be forced to redouble their efforts. 'The primordial gravitational waves have long been thought to be the smoking gun of inflation. It's as close to a proof of that theory as you are going to get,' says Peiris. This is because cosmologists believe only inflation can amplify the primordial gravitational waves into a detectable signal.

 

"'If a detection has been made, it is extraordinarily exciting. This is the real big tick-box that we have been waiting for. It will tell us something incredibly fundamental about what was happening when the universe was 10-34 seconds old,' said Prof Andrew Jaffe, a cosmologist from Imperial College, London, who works on another telescope involved in the search called Polarbear.

 

"But extracting that signal is fearsomely tricky. The microwaves that carry it must cross the whole universe before arriving at Earth. During the journey, they are distorted by intervening clusters of galaxies. 'It's like looking at the universe through bubbled glass,' said Duncan Hanson of McGill University in Montreal, Canada, who works on the South Pole Telescope, a rival that sits next to Bicep. He said the distortion must be removed in a convincing way before anyone can claim to have made the detection. The prize for doing that, however, would be the pinnacle of a scientific career. 'The Nobel Prize would be for the detection of the primordial gravitational waves.' 'Yeah, I would give them a prize,' said Jaffe." [Stuart Clarke, The Guardian, 14/03/2014. Quotation marks altered to conform with the conventions adopted at this site; several paragraphs merged to save space. Some links added. Of course, the results were duly announced.]

 

Alarm bells should have been ringing when the scientists involved announced this 'breakthrough' directly to the media, by-passing the usual peer review system. This was reminiscent of the 'discovery' of 'cold fusion' back in 1989, which was also announced directly to the media, having been subjected only to an "abbreviated peer review system". On that, see here. (This links to a PDF.)

 

So, and not unexpectedly, we were faced with this major qualification a month or so later:

 

"Cosmic inflation seen? Don't get hopes up too quickly

 

"'The wolves are circling the campfire.' That's how one cosmologist describes the reaction of some of his colleagues to last month's headline-grabbing discoveries about the early universe. One stunning claim was that the BICEP2 telescope at the South Pole had seen evidence that the universe underwent a period of rapid inflation. Another was that it had detected the imprint of long-sought gravitational waves. Those claims have since come under intense scrutiny. Some physicists now say that the team didn't adequately exclude other processes that could have given rise to the data (see 'Star dust casts doubt on recent big bang wave result' and 'Big bang breakthrough: The dark side of inflation').

 

"So is what some commentators described as the 'discovery of the century' about to be brought crashing down? There is real room for doubt about the results. Confirmation bias is as much a danger in the physical sciences as elsewhere: by setting out with a clear theoretical prediction of what they should see, the BICEP2 team may have ended up seeing exactly what they wanted to." [New Scientist 222, 2966, 26/04/2014, p.5. Quotation marks altered to conform with the conventions adopted at this site. Two paragraphs merged to save space.]

 

By June 2014, even the researchers involved had begun to question their own results:

 

"Cosmic Inflation: Confidence Lowered For Big Bang Signal

 

 

"Scientists who claimed to have found a pattern in the sky left by the super-rapid expansion of space just fractions of a second after the Big Bang say they are now less confident of their result. The BICEP2 Collaboration used a telescope at the South Pole to detect the signal in the oldest light it is possible to observe. At the time of the group's announcement in March, the discovery was hailed as a near-certain Nobel Prize. But the criticism since has been sharp.

 

"Rival groups have picked holes in the team's methods and analysis. On Thursday, the BICEP2 collaboration formally published its research in a peer reviewed journal -- Physical Research Letters (PRL). In the paper, the US-led group stands by its work but accepts some big questions remain outstanding. And addressing a public lecture in London, one of BICEP2's principal investigators acknowledged that circumstances had changed. 'Has my confidence gone down? Yes,' Prof Clem Pryke, from the University of Minnesota, told his audience.

 

"Light twist

 

"What the team announced at its 17 March press conference was the long sought evidence for 'cosmic inflation'. Developed in the 1980s, this is the idea that the Universe experienced an exponential growth spurt in its first trillionth of a trillionth of a trillionth of a second. It helps explain why deep space looks the same on all sides of the sky -- the contention being that a very rapid expansion early on could have smoothed out any unevenness. Inflation theory makes a very specific prediction -- that it would have been accompanied by waves of gravitational energy, and that these ripples in the fabric of space-time would leave an indelible mark on the oldest light in the sky -- the famous Cosmic Microwave Background.

 

"The BICEP team claimed to have detected this signal. It is called B-mode polarisation and takes the form of a characteristic swirl in the directional properties of the CMB light. It is, though, an extremely delicate pattern and must not be confused with the same polarisation effects that can be generated by nearby dust in our galaxy. The critiques that have appeared since March have largely focused on this issue. And they intensified significantly when some new information describing dust polarisation in the Milky Way was released by scientists working on the European Space Agency's orbiting Planck telescope.

 

"Planck, which everyone agrees is extremely powerful at characterising dust, will release further data before the end of the year. And, very significantly, this will include observations made in the same part of the sky as BICEP2's telescope. Until then, or until new data emerges from other sources, the BICEP2 collaboration recognises that its inflation detection has greater uncertainty attached to it. '[Our] models are not sufficiently constrained by external public data to exclude the possibility of dust emission bright enough to explain the entire excess signal,' it writes in the PRL paper.

 

"'Data trumps models'

 

"At his lecture at University College London, Prof Pryke explained his team's lowered confidence: 'Real data from Planck are indicating that our dust models are underestimates. So the prior knowledge on the level of dust at these latitudes, in our field, has gone up; and so the confidence that there is a gravitational wave component has gone down. Quantifying that is a very hard thing to do. But data trumps models.'

 

"Prof Pryke spoke of the pressure he and his colleagues had been under since March. He said he never expected there would be such interest in their work, especially from mainstream media. 'I'm feeling like I'm at the eye of the storm,' he told me. 'Look, the scientific debate has come down to this -- we need more data. With the existing data that's out there, you can generate a lot of farce, a lot of blog posts, a lot of excitement and controversy, but you can't really answer the question scientifically. So, what you need is more data, and that's coming from Planck and it's coming from us.' Prof Marc Kamionkowski, from Johns Hopkins University, commented that what we were witnessing currently was 'science in action'.

 

"'If it was not such an exciting result, you would not be hearing so much about it,' he said in a phone conversation last week. 'We're going to need confirmation by independent groups. That's the way things work in science. We don't believe things because somebody says they're true; we believe them because different people make the measurements independently and find the same results.'" [Quoted from here. Accessed 20/06/2014. Links in the original. Several paragraphs merged to save space.]

 

September 2014: The BBC now reports the following (however, it is worth recalling that a year earlier the author of the following article, Jonathan Amos, had heralded these results as "spectacular", in the same way that the rest of the media gushed effusively over this 'discovery'):

 

"Cosmic inflation: BICEP 'underestimated' dust problem

 

 

"One of the biggest scientific claims of the year has received another set-back. In March, the US BICEP team said it had found a pattern on the sky left by the rapid expansion of space just fractions of a second after the Big Bang. The astonishing assertion was countered quickly by others who thought the group may have underestimated the confounding effects of dust in our own galaxy. That explanation has now been boosted by a new analysis from the European Space Agency's (Esa) Planck satellite. In a paper published on the arXiv pre-print server, Planck's researchers find that the part of the sky being observed by the BICEP team contained significantly more dust than it had assumed. This new information does not mean the original claim is now dead. Not immediately, anyway.

 

"Cosmic 'ripples'

 

"The BICEP and Planck groups are currently working on a joint assessment of the implications, and this will probably be released towards the end of the year. However, if the contention is eventually shown to be unsupportable with the available data, it will prove to be a major disappointment, especially after all the initial excitement and talk of Nobel Prizes. What BICEP (also known as BICEP2) claimed to have done was find the long-sought evidence for 'cosmic inflation'. This is the idea that the Universe experienced an exponential growth spurt in its first trillionth of a trillionth of a trillionth of a second. The theory was developed to help explain why deep space looks the same on all sides of the sky -- the notion being that a very rapid expansion in the earliest moments could have smoothed out any unevenness.

 

"Inflation makes a very specific prediction -- that it would have been accompanied by waves of gravitational energy, and that these ripples in the fabric of space-time would leave an indelible mark on the 'oldest light' in the sky -- the famous Cosmic Microwave Background (CMB). The BICEP team said its telescope at the South Pole had detected just such a signal.... It is called B-mode polarisation and takes the form of a characteristic swirl in the directional properties of the CMB light. But it is a fiendishly difficult observation to make, in part because the extremely faint B-mode polarisation from nearly 14 billion years ago has to be disentangled from the polarisation being generated today in our Milky Way Galaxy. The main source of this inconvenient 'noise' is spinning dust grains. These countless particles become trapped and aligned in the magnetic fields that thread through our galaxy. As a consequence, these grains also emit their light with a directional quality, and this is capable of swamping any primordial background signal.

 

"The BICEP team's strategy was to target the cleanest part of the sky, over Antarctica, and it used every piece of dust information it could source to do the disentanglement. What it lacked, however, was access to the dust data being compiled by Europe's Planck satellite, which has mapped the microwave sky at many more frequencies than the American team. This allows it to more easily characterise the dust and discern its confounding effects. The Planck report in the arXiv paper details dust polarisation properties across a great swathe of sky at intermediate and high galactic latitudes. Only a very small portion of those fields is relevant to BICEP, but the results are not encouraging. There is significantly more dust in BICEP's 'southern hole' than anticipated. Indeed, most of the American signal -- perhaps all of it -- could have been attributed to dust.

 

"'It's possible, but the error in our measurement is quite high,' Planck scientist Dr Cécile Renault told BBC News. 'The conclusion really is that we need to analyse the data together -- BICEP and Planck -- to get the right cosmological [versus] galactic signal. It's really too early to say.' The American group had already downgraded confidence in its own result when it finally published a paper on the inflation claim in Physical Review Letters in June. In the eyes of many commentators, the new Planck analysis will shake that confidence still further.

 

"'Premature' announcement

 

"The Planck researchers themselves promise to report back on their own search for a primordial polarisation signal very soon (probably at the same time as the joint paper with BICEP). Their approach is different to the American one.

 

"'Planck has wider spectral coverage, and has mapped the entire sky; BICEP2 is more sensitive, but works at only one frequency and covers only a relatively small field of view,' explained Prof Peter Coles from Sussex University, who has been tracking the developing story on his blog, In The Dark. 'Between them they may be able to identify an excess source of polarisation over and above the foreground, so it is not impossible that a gravitational wave component may be isolated. That will be a tough job, however, and there's by no means any guarantee that it will work. We will just have to wait and see.'

 

"But what can be said now, adds Prof Coles, is that BICEP's March claim 'was premature, to say the least'. Even if the American and European approaches turn out to be unsuccessful this time, these groups will have pointed the way for future observations that are planned with superior technology. Planck has actually now identified parts of the sky that have less dust than the area probed by BICEP. 'If you look at the maps we've produced, the more blue parts are where you should go look for the primordial signal,' explained Dr Renault." [Quoted from here. Accessed 22/09/2014. Several paragraphs merged to save space. Quotation marks altered to conform with the conventions adopted at this site. Links in the original.]

 

Should DM-fans now issue 'gravitational waves' with their very own temporary residents' permit granting them only provisional membership status in the "Totality"? Or, maybe, tuck these dubious 'waves' in a 'dialectical broom closet' somewhere while scientists 'finally' make up their minds -- and then change them again a few years later?

 

January 2015: Surprise, surprise, we are now told that the above "spectacular" results were "mistaken":

 

"Cosmic inflation: New study says BICEP claim was wrong

 

 

"Scientists who claimed last year to have found a pattern in the sky left by the super-rapid expansion of space just fractions of a second after the Big Bang were mistaken. The signal had been confounded by light emission from dust in our own galaxy. This is the conclusion of a new study involving the US-led BICEP2 team itself. A paper describing the findings has been submitted to the peer-reviewed journal Physical Review Letters. A summary was briefly posted on an official French website on Friday before being pulled. A press release was then issued later in the day, although the paper itself is still not in the public domain at the time of writing. A determination that BICEP2 was mistaken in its observations is not a major surprise.

 

"The team itself had already made known its reduced confidence in the detection. But the new paper is significant because it is co-authored by 'rival' scientists. These are the Planck Consortium of researchers, who were operating a European Space Agency (Esa) satellite that had also been seeking the same expansion pattern. It was on the website of one of this satellite's instrument teams -- its High Frequency Instrument (HFI) -- that the outcome of the joint assessment was briefly leaked on Friday. All the unified effort can do, according to the Esa press release, is put an upper limit on the likely size of the real signal. This will be important for those future experiments that endeavour to make what would still be one of the great discoveries in modern science.

 

"Issues of confusion

 

"BICEP2 used extremely sensitive detectors in an Antarctic telescope to study light coming to Earth from the very edge of the observable Universe -- the famous Cosmic Microwave Background (CMB) radiation. It was looking for swirls in the polarisation of the light. This pattern in the CMB's directional quality is a fundamental prediction of 'inflation' -- the idea that there was an ultra-rapid expansion of space just fractions of a second after the Big Bang. The twists, known as B-modes, are an imprint of the waves of gravitational energy that would have accompanied this violent growth spurt almost 14 billion years ago. But the primordial signal -- if it exists -- is expected to be extremely delicate, and a number of independent scientists expressed doubts about the American team's findings as soon as they were announced at a press conference in March 2014.

 

"At issue are a couple of complications. One is an effect where a 'false' B-mode signal can be produced on the sky by the CMB passing through massive objects, such as huge galaxies. This so-called lensing effect must be subtracted. But the second and most significant issue is the confusing role played by foreground dust in our galaxy. Nearby spinning grains can produce an identical polarisation pattern, and this effect must also be removed to get an unambiguous view of the primordial background signal.

 

"Bright dust

 

"The BICEP2 team used every piece of dust information it could source on the part of the sky it was observing above Antarctica. What it lacked, however, was access to the dust data being compiled by the Planck space telescope, which had mapped the microwave sky at many more frequencies than BICEP2. This allowed Planck to more easily characterise the dust and discern its confounding effects. The Planck Consortium agreed to start working with BICEP2 back in the summer. The European group incorporated its high frequency information -- where dust shines most brightly -- and the US team added additional data collected by its next-generation instrument in Antarctica called the Keck Array.

 

"However, the results of the joint assessment would suggest that whatever signal BICEP2 detected, it cannot be separated at any significant level from the spoiling effects. In other words, the original observations are equally compatible with there being no primordial gravitational waves. 'This joint work has shown that the detection of primordial B-modes is no longer robust once the emission from galactic dust is removed,' Jean-Loup Puget, principal investigator of Planck's HFI instrument, said in the Esa statement. 'So, unfortunately, we have not been able to confirm that the signal is an imprint of cosmic inflation.'

 

"Ongoing quest

 

"This is not the end of the matter. Other experiments are still chasing the B-mode signal using a variety of detector technologies and telescopes. These groups will have learnt from the BICEP experience and they will all devour Planck's latest batch of relevant data products when they start to be published next week. Like any field of scientific endeavour, advances are continually being made.

 

"One of the ironies of this story is that BICEP itself may now actually be best paced to make the ultimate detection of the cosmic inflation pattern. Although the past year, with its quashed claim, will have been painful, the team will have new insights. What is more, it can still boast world-leading scientists among its members, and detectors that are universally acknowledged to be top-notch." [Quoted from here; accessed 02/02/2015. Quotation marks altered to conform with the conventions adopted at this site. Several paragraphs merged to save space. Minor typo corrected.]

 

February 2015: This from Physics World:

 

"Galactic dust sounds death knell for Bicep2 gravitational wave claim

 

"Astronomers working on the Background Imaging of Cosmic Extragalactic Polarization (BICEP2) telescope at the South Pole have withdrawn their claim to have found the first evidence for the primordial 'B-mode' polarization of the cosmic microwave background (CMB). The claim was first made in March 2014 and this update comes after analysis of data from the Keck Array telescope at the South Pole and the most up-to-date maps showing polarized dust emission in our galaxy from the European Space Agency's Planck collaboration. It now seems clear that the signal initially claimed by BICEP2 as an imprint of the rapid 'inflation' of the early universe is in fact a foreground effect caused by dust within the Milky Way.

 

"Cosmologists believe that when the universe was very young -- a mere 10–35 s after the Big Bang -- it underwent a period of extremely rapid expansion known as 'inflation when its volume increased by a factor of up to 1080 in a tiny fraction of a second. About 380,000 years after the Big Bang, the CMB -- the thermal remnant of the Big Bang -- came into being. BICEP2, Planck and the Keck Array all study the CMB and BICEP2's main aim was to hunt down the primordial B-mode polarization. This 'curl' of polarized CMB light is considered to be the smoking gun for inflation.

 

"In March last year BICEP2 scientists claimed success, saying that they had measured primordial B-modes with a statistical certainty of 7σ -- well above the 5σ 'gold standard' for a discovery in physics. However, doubts soon crept in, especially about how the team had handled the effect of galactic dust on the result. Also, the BICEP2 measurements used in the 2014 analysis were made at just one frequency of 150 kHz -- for a signal to be truly cosmological in nature, it must be crosschecked at multiple frequencies.

 

"Dusty data

 

"When the most recent dust maps from Planck were released in September last year, it became apparent that the polarized emission from dust is much more significant over the entire sky than BICEP2 had allowed for. While the dust signal is comparable to the signal detected by BICEP2 even in the cleanest regions, this did not completely rule out BICEP2's original claim. To put the issue to rest, the three groups of scientists analysed their combined data -- adding into the mix the latest data from the Keck Array, which also measures CMB polarization.

 

"This analysis was based on CMB polarization observations on a 400 square-degree patch of the sky. The Planck data cover frequencies of 30-353 GHz, while the BICEP2 and Keck Array data were taken at a frequency of 150 GHz. 'This joint work has shown that the detection of primordial B-modes is no longer robust once the emission from galactic dust is removed,' says Jean-Loup Puget, principal investigator of the HFI instrument on Planck at the Institut d'Astrophysique Spatiale in Orsay, France. 'So, unfortunately, we have not been able to confirm that the signal is an imprint of cosmic inflation.' While they did find a signal from B-modes that arose due to gravitational lensing from galaxies, which had been spotted before in the CMB, it is not the primordial signal the groups were looking for.

 

"Since its public announcement in March 2014, the BICEP2 team has been criticized by some physicists for prematurely claiming to have found the first 'smoking gun' evidence for inflation. Neil Turok, director of the Perimeter Institute of Theoretical Physics in Canada, who had been an early critic of the BICEP2 results, now points out that the latest joint analysis has shied away from making a clear comparison of the data against the most basic models of inflation. 'These data imply that the simplest inflation models are now ruled out with 95% confidence,' he says, explaining that, while this is not yet conclusive, it may just be just a matter of time thanks to a host of experiments that are currently gathering new and better data on the B-modes. Indeed, Turok believes that within a year we may have the data that begins to winnow away many inflationary theories. One such basic theory -- dubbed the Φ2 theory -- predicts a 15% contribution in the CMB fluctuations to come from primordial gravitational waves, but the data from the joint analysis show that the maximum contribution is 12%. Turok told physicsworld.com he would not be surprised if this contribution were shown to be a mere 5% in the next year.

 

"Bandwagon jumping

 

"Peter Coles, an astrophysicist at the University of Sussex in the UK, told physicsworld.com that, with data at only one frequency, there was no way BICEP2 could have ruled out dust emission. 'I think they were right to publish their result, but should have been far more moderate in their claims and more open about the uncertainty, which we now know was huge,' he says. 'I don't think BICEP2 comes out of this very well, but neither do the many theorists who accepted it unquestioningly as a primordial signal and generated a huge PR bandwagon.'

 

"Coles adds that, despite what has happened, he still believes strongly in open science. 'The BICEP2 debacle has really just demonstrated how science actually works, warts and all, rather than how it tends to be presented in the media. But I do feel that it has exposed a worrying disregard for the scientific method in some very senior scientists who really should know better. It can be dangerous to want your theory to be true so much that it clouds your judgement. In the end it's the evidence that counts.'

 

"Caught in a loop?

 

"Following BICEP2's announcement last March, Subir Sarkar -- a particle theorist at the University of Oxford and the Niels Bohr Institute in Copenhagen -- claimed to have found evidence that emissions from local "radio loop" structures of dust in our galaxy could generate a previously unknown polarized signal. This new foreground -- which should be seen in the radio and microwave frequencies and is present at high galactic latitudes -- could easily mimic a B-mode polarization signal, according to Sarkar.

 

"Planck's data from last year convinced Sarkar and colleagues that the loop structures crossing the BICEP2 observation region may be the main cause of the polarization signal. Sarkar told physicsworld.com that he is surprised that the latest paper does not offer a physical explanation for why there should be so much dust at such high galactic latitudes. 'Unless we understand this it will be hard to model the foreground emission to the level of accuracy required to make progress in the continuing search for gravitational waves from inflation,' he says. Currently, a variety of satellite and ground-based experiments -- such as LiteBIRD, COrE, Atacama Cosmology Telescope and the recently launched SPIDER telescope -- are busy taking measurements of the CMB polarization to settle the debate on gravitational waves, and hence inflation. Indeed, the BICEP experiment itself is now taking data at two frequencies and will soon up that number to three.

 

"Theories run amok

 

"'For the past 35 years, theoretical physics has been an extravaganza of model-building,' says Turok, adding that theories have 'sort of run amok.' He alludes to the fact that data from experiments as different in scale as the Large Hadron Collider and Planck have shown that the universe 'is much simpler than we expected'. The data in the coming years will show whether or not relics of gravitational waves indeed abound in the universe -- or if inflationary theories should be consigned to the dusty corners of history.

 

"The paper 'A joint analysis of BICEP2/Keck Array and Planck data' by BICEP2/Keck and the Planck collaboration has been submitted to the journal Physical Review Letters. A pre-print is available here." [Quoted from here; accessed 13/03/2015. Quotation marks altered to conform with the conventions adopted at this site. Links in the original; bold emphasis added. Several paragraphs merged to save space.]

 

Fortunately, this means that the DM-committee that decides on such matters (if there is one!) can now strike these 'waves' from the "Totality's"  roll call -- or, at least it can do so until some other premature and over-hyped 'results' send the world's media into another hysterical spin.

 

~~~~~oOo~~~~~

 

Lo and behold, in February 2016 we were informed that gravitational waves had finally been discovered! A second result later that year confirmed this phenomenon.

 

However, the original result in February met with the same acclaim that greeted the now debunked BICEP results above. Clearly, it is far too early to tell if this discovery will also be 'corrected' at some point, and then quietly abandoned.

 

Maybe the DM-selection panel can help out here?

 

Time To Ditch 'Dark Matter'?

 

May 2014: Materialists -- let alone scientists -- should have displayed a healthy scepticism toward the idea that 80-90% of the matter in the universe is 'invisible' (i.e., undetectable), despite the fact that we have time and again seen researchers accept the 'existence' of any number of weird and wonderful objects and processes, many of which were (indeed, still are) no less invisible and undetectable, which they later rejected or quietly forgot about.

 

This, from a recent edition of the New Scientist:

 

"It's time to give up on dark matter

 

"It supposedly makes up 80 per cent of the matter in the universe, but we still have no direct evidence that dark matter exists. Physicist Mordehai Milgrom tells Marcus Chown that it's time to abandon the idea -- because he has a better one

 

"Why is now a good time to take an alternative to dark matter seriously?
 

"A host of experiments searching for dark matter, including the Large Hadron Collider, many underground experiments and several space missions, have failed to see anything convincing. This comes on top of increasing realisation that the leading dark matter model has its failings. Among other things, it predicts that we should see many more dwarf galaxies orbiting our Milky Way than we actually do. Set against this is the fact that in the past two years, numerous observations have added support to my proposed alternative, modified Newtonian dynamics (MOND).

 

"What does dark matter explain?
 

"To give one example, according to Newton's laws of motion and gravitation, stars at ever greater distances from the centre of a spiral galaxy should orbit the centre ever more slowly because of the rapid drop-off in gravity. But this doesn't happen. The mainstream explanation is that every spiral galaxy, including our Milky Way, is embedded in a 'halo' of dark matter that enhances gravity at the galaxy's outer regions, preventing stars from simply flying off into intergalactic space. But for that to work, you have to give each galaxy its own arbitrary amount and distribution of dark matter.

 

"So what is MOND, your alternative?
 

"I believe that galaxies are governed by laws that differ from Newton's. According to MOND, the faster-than-expected motion of stars in the outer regions of spiral galaxies could be due to either a new law of gravity that yields a stronger-than-expected force or a new law that reduces the inertia of stars. This departure from Newtonian dynamics occurs when the acceleration of stars drops below a hundred billionth of a g, which happens at different distances from the centre in different galaxies. So, with a single parameter, MOND can predict the rotation curves of all galaxies with no need for dark matter.

 

"What new evidence is there for MOND?


"I will mention just two recent findings. In what's known as galaxy-galaxy lensing, light from distant galaxies is distorted as it passes by nearer galaxies on its way to Earth. This enables us to probe the gravitational field of millions of galaxies of all types -- not just spiral galaxies, where it is easy to see MOND at work. Predictions made using MOND agree well with recent observations (Physical Review Letters, vol 111, p.041105).

 

"Other evidence comes from our neighbouring galaxy Andromeda. Because MOND assumes that there is no dark matter, it must predict the velocity of stars orbiting in a galaxy from the distribution of visible matter alone. Last year, with Stacy McGaugh at Case Western Reserve University in Cleveland, Ohio, we predicted the velocities of stars in about 30 dwarf satellite galaxies of Andromeda. When these velocities were actually measured, our predictions proved correct (The Astrophysical Journal, vol 775, p.139). The main dark matter paradigm has no such predictive power; it can only explain after the event.

 

"When did you first come up with this alternative to dark matter?


"More than 30 years ago, I began to wonder whether the gravitational dynamics changed at a particular distance from the centre of a galaxy. That didn't appear to be the case. I tried a few other things and, finally, in April 1981, I hit on acceleration. The meagre data we had then could be explained if at a critical acceleration -- a mere hundred billionth of a g -- gravity switched from a type that weakens in line with the familiar Newtonian law to a type that falls off more slowly, following a different law. That alternative law is MOND. At first, I didn't tell anyone. Only after working on the idea for six more months did I announce it in three papers. By and large, they were met by silence.

 

"Why didn't most people take it seriously?


"Dark matter was the hypothesis of least daring -- just add some gravitating stuff that gives out no light. Modifying dynamics, on the other hand, meant tampering with fundamental things such as Newton's and Einstein's theories of gravity. That appalled people. Also, initially, the theory applied only to nonrelativistic systems -- with constituents that move slowly compared with light. To be taken seriously, MOND had to be made compatible with Einstein's principles of relativity.

 

"So how did you solve that problem?


"It took a while, but in 2004 Jacob Bekenstein at the Hebrew University of Jerusalem put forth a theory known as TeVeS (tensor-vector-scalar). It built on his earlier work with Bob Sanders at the University of Groningen in the Netherlands. TeVeS describes gravity with three fields and made MOND compatible with Einstein's relativity. After it was introduced, people started to take MOND more seriously.

 

"Is MOND more elegant than dark matter?
 

"It is certainly far more economical. For every galaxy, dark matter theorists must fit a made-to-measure amount and distribution of dark matter. So, if we understand 10 galaxies, we still don't understand an 11th. Dark matter explains only after the fact. MOND predicts things ahead of time. This is key.

 

"What do the dark matter theorists say to this?


"They believe the problems with dark matter will one day be solved. A single MOND formula perfectly describes every spiral galaxy, even though the birth of each one is chaotic, complex and unique. It is hard to see how the dark matter model can explain this. Still, they cling to the hope that it will one day be possible. To my mind there is no hope of that happening.

 

"Does it bother you that most physicists remain dismissive of your idea?


"Fifteen years ago, I found it somewhat dismaying. Now my spirits are up. There has been an explosion in interest. In recent years, around 700 papers dealing with MOND have been published. It's very encouraging.

 

"What killer observation could support MOND?
 

"Well, if dark matter is discovered, that would kill MOND. But I don't think there is one killer observation that will clinch the idea in the minds of dark matter advocates. Hundreds of MOND predictions have been vindicated already; what more can one ask for?

 

"How long should we keep looking before giving up on dark matter?

 

"The ongoing, failed attempts to find it actually benefit MOND, so I would like to see the search continue. To my mind it is already high time to give up on dark matter. So much time, money and effort can be saved. Human nature being what it is, that might take 10 years or longer. I envision a gradual disillusionment as dark matter continues not to turn up in experiments. Even Einstein's theory of gravity was accepted only slowly. So I'm not despairing. Far from it.

 

"Mordehai Milgrom is professor of physics at the Weizmann Institute of Science in Rehovot, Israel. He proposed the theory of modified Newtonian dynamics (MOND) as an alternative to dark matter." [New Scientist 222, 2967, 03/05/2014. Quotation marks altered to conform with the conventions adopted at this site; several paragraphs merged to save space. Some links added. Emphases in the original.]

 

March 2015: The BBC has just aired a programme entitled "Dancing In The Dark -- The End Of Physics". As the search for 'Dark matter' seems to be stalling, if not running into the sand, the astrophysicists who appeared in the programme were perhaps being a little too honest. Among the choice comments they came out with were the following:

 

"Maybe we're just going to have to scratch our heads and start all over again." (Professor John Ellis) "How does any theorist sleep at night knowing that The Standard Model of particle physics is off by so many orders of magnitude?" (Professor Leslie Rosenberg) "We have no idea what 95% of the universe is. It hardly seems we understand everything!" (Professor David Charlton) "What is it they say about Cosmologists? They are always wrong but never in doubt." (Professor Juan Collar) "There are more theories than there are theoreticians." (Professor Bob Nichol) "I'm not the hugest fan of SUSY [Supersymmetry -- RL]; it seems slightly messy the way you just add in one extra particle for every other particle that we know about." (Dr Katherine Leney) "People have been looking for SUSY for decades, and we have been building bigger and bigger machines, and its always been just always out of reach.... It's getting to the point where now with the LHC [Large Hadron Collider -- RL] it's going up in energy and that's such a huge reach now, if we still don't find it then...it starts to look like it's not the right idea." (Dr Gavin Hesketh)

 

This is from the BBC's Science News page:

 

"Dancing in the dark: The search for the 'missing Universe'

 

 

"They say the hardest pieces of music to perform are often the simplest ones. And so it is with science -- straightforward questions like what is the Universe made from? have so far defeated the brightest minds in physics. Until -- perhaps -- now. Next week, the Large Hadron Collider at Cern will be fired up again after a two-year programme of maintenance and upgrading. When it is, the energy with which it smashes particles will be twice what it was during the LHC's Higgs boson-discovering glory days. It is anticipated -- hoped, even -- that this increased capability might finally reveal the identity of 'dark matter' -- an invisible but critical entity that makes up about a quarter of the Universe. This is the topic of this week's Horizon programme on BBC Two.

 

"Dark matter arrived on most scientists' radar in 1974 thanks to the observations of American astronomer Vera Rubin, who noticed that stars orbiting the gravity-providing black holes at the centre of spiral galaxies like ours did so at the same speed regardless of their distance from the centre. This shouldn't happen -- and doesn't happen in apparently comparable systems like our Solar System, where planets trapped by the gravity of the sun orbit increasingly slowly the further away they find themselves. Neptune takes 165 Earth years to plod around the Sun just once. This is what our understanding of gravity tells us should happen. Vera's stars racing around at the same speed were a surprise: there had to be more stuff there -- providing more gravity -- than we could see. Dark matter.

 

"Dark matter, then, is a generic term for the stuff (matter) that must be there but which we can't see (dark). But as to what this dark matter might actually be, so far science has drawn a blank. That's not to say that there's been no progress at all. It's now thought that dark matter isn't just ordinary stuff in the form of gas and dust and dead stars that are dark simply because they don't shine. It's now generally agreed that the dark matter is a miasma of (as yet unidentified) fundamental particles like (but not) the quarks and gluons, and so on, that make up the atoms with which we're more familiar.

 

"These 'dark' fundamental particles are known as Wimps: Weakly Interacting Massive Particles. This acronym, like the term 'dark matter' itself, is a description of how these theoretical dark matter creatures behave, rather than a definition of what they are: The 'weakly interacting' bit means that they don't have much to do with ordinary matter. They fly straight though it. This makes them very tricky to detect, given that ordinary matter is all we have to detect them with. The 'massive' part means simply that they have mass. It has nothing to do with their size. All that's left is 'particle', which means, for want of a better description, that it's a thing. [That certainly clears things up! -- RL.]

 

"So dark matter is some form of fundamental particle that has Wimp characteristics. In theory, these Wimps could be a huge range of different things, but work done by Prof Carlos Frenk of Durham University has narrowed the search somewhat. It was Frenk and his colleagues who, at the start of their scientific careers in the 1980s, announced that dark matter had to be of the Wimp type and, additionally, it had to be 'cold'. At the time, it was a controversial claim, but in the years since, Frenk has added computerised flesh to the bones of the theory -- by making universes.

 

"'It's quite a simple process,' says Frenk. 'All you need is gravity and a few basic assumptions.' Key among these basic assumptions is Frenk's claim that dark matter is of the Wimp variety, and cold. The universes that emerge from his computer are indistinguishable from our own, providing a lot of support to the idea of cold dark matter. And because dark matter is part of the simulation, it can be made visible. The un-seeable revealed. 'You can almost touch it!' enthuses Frenk. But so far, 'almost' is the issue. The fact is that you can't touch it -- which is why tracking it down 'in the wild' has, to date, ended in disappointment. And yet it must be there, and it must be a fundamental particle -- which is where Cern's Large Hadron Collider comes in.

 

"What happens in the LHC is that protons are fired around its 27km-long tube in opposite directions. Once they've been accelerated to almost the speed of light, they're collided -- smashed together. This does two things. Firstly, it makes the protons disintegrate, revealing the quarks, gluons and gauge bosons and the other fundamental particles of atomic matter. There are 17 particles in the standard model of particle physics -- and all of them have been seen at the LHC.

 

 

"Secondly, the collisions might produce other, heavier particles. When they do, the LHC's detectors will record them. In charge of one of those detectors is Prof Dave Charlton from the University of Birmingham. 'Sometimes you produce much more massive particles. These are the guys we're looking for.' Dave -- and everyone else at Cern -- is looking for them because they could be the particles that could be the dark matter. It all sounds highly unlikely -- the idea that ordinary matter produces matter you can't see or detect with the matter that made it -- but it makes sense in terms of the uncontroversial concept of the Big Bang.

 

"If dark matter exists, it would have been produced at the Big Bang like everything else. And to see what actually was produced at the big bang, you need to create the conditions of the Big Bang -- and the only place you're likely to get anywhere near those conditions is at the point of collision in the LHC. The faster the collision, the closer you get to the Big Bang temperature. So there's every reason to think that dark matter might well be produced in particle accelerators like the LHC.

 

"What's more, there's a mathematical theory that predicts that the 17 constituents of the standard model are matched by 17 more particles. This is based on a principle called 'super symmetry'. Prof John Ellis, a theoretical physicist from Kings College, London, who also works at Cern, is a fan of super symmetry. He's hopeful that some of these as yet theoretical super symmetrical particles will show up soon.

 

"'We were kind of hoping that they'd show up in the first run of the LHC. But they didn't,' he confesses, ruefully. Ellis explains that what that means is that the super symmetric particles must be heavier than they thought, and they will only appear at higher energies than have been available -- until now. In the LHC's second run, its collisions will occur with twice as much energy, giving Prof Ellis hope that the super symmetric particles might finally appear. 'When we increase the energy of the LHC, we'll be able to look further -- produce heavier super symmetric particles, if they exist. Let's see what happens!'

 

"It's crunch time for super symmetry. If it shows itself in the LHC, then all will be well. The dark matter problem would finally be solved, along with some other anomalies in the standard model of physics. But if, like last time, super symmetry fails to turn up, physicists and astrophysicists will have to come up with some other ideas for what our Universe is made from.

 

"'It might be," concedes Prof Ellis, 'that we'll have to scratch our heads and start again.'

 

"Dancing in the Dark -- The End of Physics? is broadcast on BBC Two on Tuesday 17 March at 21:00." [Quoted from here; accessed 19/03/2015. Quotation marks altered to conform with the conventions adopted at this site. Paragraphs merged to save space; bold emphases and one link added.]

 

I'll refrain from making the same points or asking the obvious questions -- again -- but by now I'm sure readers will know what they are...

 

Periodic Table -- About To Decay?

 

July 2014: Is this bad news for 'scientific realists'?

 

"Rogue elements: What's wrong with the periodic table?

 

[A copy of The Periodic Table has been posted at the end of this article -- RL.]

 

"14 July 2014 by Celeste Biever

 

"If imitation is the sincerest form of flattery, the periodic table has many true admirers. Typefaces, types of meat and even the Muppets have been ordered in its image. For chemists, knowing an element's position in the periodic table, and the company it keeps, is still the most reliable indicator of its properties -- and a precious guide in the search for new substances. 'It rivals Darwin's Origin of Species in terms of the impact of bringing order out of chaos,' says Peter Edwards of the University of Oxford. The origins of the periodic table lie in the 19th century, when chemists noticed that patterns began to emerge among the known chemical elements when they were organised by increasing atomic weight. In the 1860s, Dmitri Mendeleev and others began to group the elements in rows and columns to reflect those patterns -- and realised gaps in the resulting grids allowed them to predict the existence of elements then unknown.

 

"It was only with the advent of quantum theory in the 20th century that we began to grasp what lies behind these patterns. The periodic table's rows and blocks roughly correspond to how an atom's electrons are arranged, in a series of 'shells' around the proton-rich nucleus. Electrons fill shells and subdivisions of shells starting with the one closest to the nucleus, which has the lowest energy. The number of electrons in the outermost shell, and its distance from the nucleus and the other shells, are the main factors that determine an element's chemical behaviour. 'Chemical periodicity is a natural property,' says Eric Scerri, a philosopher of chemistry at the University of California, Los Angeles.

 

"But that perhaps leads us to some hasty conclusions about the table. 'People assume surely it's been sorted out. It's not settled -- many, many aspects are still up for grabs,' says Scerri. Electron configurations do not always mesh neatly with chemical properties. Properties and patterns we take as given on Earth are very different when we venture into the extreme environment of space. And quite what happens towards the end of the periodic table -- and indeed, where this end lies -- are questions that remain unanswered. As the following examples show, the periodic table is still very much a work in progress…

 

"Weighty affair

 

"The earliest periodic tables arranged elements by ascending atomic weight -- basically, the number of protons and neutrons in an atom's nucleus. But most atoms come in various isotopes containing different numbers of neutrons. Today's tables order the elements by atomic number -- the unambiguous number of protons. The atomic weights are still there -- but the question is, which is the 'correct' one? They used to be displayed as a single number for each element, based on averaging the weights of its natural isotopes according to their relative abundances. But this perpetuates the misconception that this number is some kind of fundamental constant, says Tyler Coplen of the Reston Stable Isotope Laboratory in Virginia. In reality, the atomic weight of an element such as carbon, say, varies slightly from sample to sample depending on the exact quantities of each isotope.

 

"In 2009 the guardians of the table, the International Union of Pure and Applied Chemistry (IUPAC), took action, removing the set atomic weights of 10 elements including hydrogen, lithium, boron, carbon, nitrogen and sulphur, and replacing them with ranges encompassing the isotopic spreads in all known terrestrial samples. Bromine and magnesium followed in May 2013. Nickel, selenium and zinc are probably next up. Not all elements are so flighty, though. Fluorine, aluminium, sodium, gold and 17 other elements have only one stable isotope, meaning their atomic weight really is a constant of nature. Their weights can stay, then.

 

"Three's company?

 

"Ordering the periodic table by atomic number makes the position of elements indisputable -- except when it doesn't. Take the case of the two rows of elements floating rather like an afterthought below the main body of the table: the lanthanides and actinides. Two gaps in the main table, below scandium and yttrium in group 3, mark where these series slot in. The question is, how do they slot in? There are two schools of thought. One goes by electron configurations: scandium and yttrium both have three outer electrons, as do lanthanum and actinium, the elements at the left-hand end of the series, so they are the rightful placeholders. But others point out that chemical properties such as atomic radius and melting point make lutetium and lawrencium at the right end of the rows a better fit. In 2008, simmering tensions between the two sides boiled over in the pages of the Journal of Chemical Education.

 

"Resolving the dispute matters, says Scerri, and not just for pedagogical clarity. Yttrium can be used to make superconductors, compounds that conduct electricity without resistance, that work at relatively high temperatures. The hunt is on for materials with similar abilities and Scerri thinks lutetium and lawrencium compounds may have been overlooked because they are seen as belonging to a completely unrelated group. Any resolution will be years away. IUPAC has given Scerri the go-ahead to set up a committee -- but only to make the case for why a decision might be needed.

 

"Half empty -- or half full?

 

"In the early universe, the two simplest elements, hydrogen and helium, were pretty much all there was. But the advent of more complex stuff has made it difficult to work out where they fit in. 'It's a bit like asking how would you classify dinosaurs along with other animals,' says Scerri.

 

"Hydrogen has one proton surrounded by one electron rattling around in a shell that might hold two. But is that shell half-empty or half-full? Most elements tend to either gain or lose electrons during chemical reactions. Hydrogen swings both ways, sometimes picking up an electron to fill its shell and form compounds like sodium hydride (NaH), and sometimes losing its one electron to form compounds like hydrogen fluoride (HF). Most periodic tables, including IUPAC's, put hydrogen in group 1 with electron-losing metallic elements such as lithium and sodium. But even IUPAC allows that hydrogen might sit equally well with electron-scarfing halogens such as fluorine right over in group 17. Most chemists shrug at this ambiguity. 'It doesn't bother me to include hydrogen both in group 1 and in group 17,' says Pekka Pyykkö of the University of Helsinki in Finland.

 

"The problem with helium, meanwhile, is that it hardly reacts at all, thanks to its full outer electron shell. In a standard periodic table it sits atop neon with the noble gases that share this characteristic, in group 18. But the fact its outer shell contains only two electrons makes some suspect it would be better off with elements such as beryllium, over in group 2. That suspicion is increased by calculations indicating that both helium and neon might under certain circumstances react with other elements, but that helium is the more likely to. This goes against the trend of increasing reactivity as you go down that group -- a wrinkle that could also be smoothed, some suggest, by spiriting helium away to group 2.

 

"When is a metal not a metal?

 

"It was a trend that made the pioneers of the periodic table confident they were on to something: if you sweep diagonally across the periodic table from bottom left to top right, the elements gradually become less metallic. Commonly, the boundary between the two is depicted as a thick line staircasing its way down the table's right side. Sadly, it isn't that simple. 'Metal-non-metal status isn't sacrosanct,' says Edwards. Take hydrogen. We Earthlings encounter it as a distinctly non-metallic transparent gas. But in the cores of hydrogen-rich planets such as Jupiter and Saturn, high pressures and temperatures are thought to make hydrogen a shiny, metallic fluid. Its usual position in the periodic table, above metallic lithium, hints at this. But avowed non-metals such as helium or oxygen are also expected to loosen up under pressure, so their outermost electrons roam free to conduct as they see fit. 'The periodic table as you learned it is only the periodic table at ambient conditions,' says Friedrich Hensel of the University of Marburg in Germany.

 

"Hydrogen under pressure might even make a solid metal, a substance with possibly exciting applications as a fuel or room-temperature superconductor -- although recent claims to have made it in the lab are disputed. It goes the other way, too. In 2009, a team led by Artem Oganov, now at the State University of New York at Stony Brook, used high pressures to turn the shiny group 1 metal sodium into a translucent, reddish-orange non-metal. In this case, it seems the pressure brings electrons so close that they are forced to occupy spots that minimise subsequent repulsions, instead of roaming free. Such questionable behaviours highlight that there is little settled in the chemical world, but we shouldn't panic, says Oganov. 'I don't think we need to revise the periodic table. What we are doing now is making very important comments and corrections to it.'

 

"Einstein's influence

 

"Einstein's relativity bends space, time, minds -- and the periodic table. By the time you reach gold, with an atomic number 79, the pull of the highly charged nucleus is such that the innermost electrons whizz round at a zippy 80 per cent of the speed of light. This increases their mass, causing them to orbit the nucleus more closely and shield electrons further out from its pull. The outer shells then expand -- and the neat connection between how electrons fill up shells and an element's chemical properties begins to break down. The knock-on effects on the wavelengths of light that gold absorbs are why it looks so very different from the precious metal directly above it in the periodic table. 'You need relativity to actually make gold different from silver,' says Pyykkö. That's not the only thing. Just last year, Peter Schwerdtfeger at Massey University in Auckland, New Zealand, finally proved something suspected for decades: that mercury's anomalously low melting point, causing it uniquely among metals to be a liquid at room temperature, is also down to relativistic effects.

 

"As ever heavier elements are added to the periodic table, where does this leave things? We're not quite sure. When the properties of rutherfordium (atomic number 104) and dubnium (105) were found to be out of keeping with hafnium and tantalum immediately above them, questions were asked. But seaborgium (106) seems stolidly conventional. Element 107 has been dubbed 'boring bohrium' for the way it toes the group line. Experiments with two of the table's recent additions, copernicium (112) and flerovium (114), have so far painted a mixed picture. So has Einstein deprived the periodic table of its predictive power? Pyykkö is relaxed about the ructions. 'You don't have a simple mathematical theory underlying the periodic table,' he says. 'You have a number of nuts and bolts -- one is relativity. When put together, they explain the workings of the periodic table.' Matthias Schädel, who studies superheavy elements at the GSI Helmholtz Centre for Heavy Ion Research in Darmstadt, Germany, is less sanguine. 'The periodic table is still intact -- but you can't predict detailed properties any more,' he says.

 

"Where will it all end?

 

"Early atomic models indicated that, above an atomic number of 103, the repulsive force between positively charged protons would become so great that atoms would just fall apart. Nature generally gives up at 92, with uranium. But thanks to experiments to fabricate elements beyond uranium in the lab, the heaviest atom now officially recognised is livermorium (116). Elements 117 and 118, already fabricated, are yet to be legitimised. Clearly, where the end of the table lies isn't that simple. 'There certainly is a limit,' says Schädel, 'but we don't know where it is.' The existence of superheavy elements with atomic numbers above 103 is now explained by theories that say that, just as orbiting electrons are arranged in shells, so too are protons and neutrons within the nucleus. In and around specific 'magic' numbers corresponding to full shells, atoms are more stable. But there must still come a point where the fields within highly charged, weighty atoms will become irresistible. One suggestion, from theorist Paul Indelicato of the Pierre and Marie Curie University in Paris, France, and his colleagues in 2011, is that quantum instabilities within these fields will finally do for elements above number 172.

 

"Stability is only ever relative with the superheavy elements, anyway: those made so far are radioactive and often only survive for fractions of a second before decaying, making them difficult to study. What's more, most of them can only be produced one atom at a time, meaning chemical properties such as volatility, conductivity, or whether something is a solid, liquid or gas, cease to make much sense. So do they really count as elements at all? 'As a chemist, you want to see chemical interactions,' says Schädel. Several research teams have devised ingenious ways to study the properties of single atoms. One experiment has probed the volatility of copernicium and flerovium by comparing what temperature a single atom sticks to a gold surface with the sticking point of atoms whose volatility is known. Theory also indicates a higher sticking temperature could be evidence for a metallic character. 'Chemists and physicists have defined metal for generations but they never had to think about what happens with one atom,' says Schädel. 'This is a completely new way of defining a metal.'

 

"Even so, with no realistic prospect of exploiting these superheavy atoms, isn't this a fool's errand? Schädel thinks not, and sees such experiments in the 150-year tradition that have made the periodic table the iconic chart of the elements it is. 'It's experiencing terra incognita, going to regions that no one has a glimpsed yet,' he says." [New Scientist 223, 2977, 12/07/2014, pp.38-41. Accessed 05/09/2014. Links in the original, several paragraphs merged to save space. Quotation marks altered to conform with the conventions adopted at this site.]

 

 

Figure One: The Periodic Table

 

September 2015: And then there is this from the New Scientist:

 

"Modern-day alchemy is putting the periodic table under pressure

 

"It is chemistry's poster child. From copper's conductivity to mercury's mercurial liquidity, the periodic table assigns the chemical elements to neat columns and rows and so reveals their properties. It is chemists' first reference point in all their endeavours, whether building better catalytic converters, making concrete set faster or looking for the best materials for medical implants. Yet this iconic picture of science is hopelessly parochial. Most of the known matter in the universe doesn't exist under the cool, calm conditions of Earth's surface that the periodic table assumes. By mass, more than 99.9 per cent of normal matter resides within planets and stars -- environments of high temperatures, but above all unimaginable pressures.

 

"Here, the elements' familiar identities start to blur. 'We essentially have a new periodic table at high pressures,' says materials scientist Paul Loubeyre of the Alternative Energies and Atomic Energy Commission (CEA) in Bruyères-le-Châtel, France. As yet, this high-pressure realm is one we know little about -- proportionally as if, in thousands of years of Earth exploration, geographers had mapped out a region no larger than Spain.

 

"Slowly, however, modern-day alchemists are ratcheting up the pressure. As they do, they are transforming the familiar physical and chemical properties of elements from hydrogen to iron, turning liquids to solids, non-metals to metals and more besides. The aim is not just to understand more about the deep chemistry of our planet and others, but also to find materials that react more efficiently, store energy more effectively, or even perform that most yearningly sought-after of tricks: conducting electricity without resistance at room temperature.

 

"Electron squash

 

"It was the Russian chemist Dmitri Mendeleev who, back in 1869, produced the first recognisable periodic table. He showed that patterns begin to emerge in the properties of the chemical elements if you order them by their atomic weight, and used those patterns to predict the existence of undiscovered elements. But it wasn't until the advent of quantum mechanics in the 20th century that those patterns were explained. Electrons circling an atom's nucleus can only occupy discrete 'orbitals', each of which accepts a strict number of electrons. The distribution of electrons within these orbitals -- especially the outermost ones -- determines an element's chemical character.

 

"There are still niggles about the periodic table's validity under normal conditions (New Scientist, 12 July 2014, p.38), but turning up the pressure changes things entirely. Atoms get squished, deforming the 'unit cells' that define matter's basic scale. Electrons squeeze into tighter orbitals, overlapping and forming more exotic configurations, and begin making chemical bonds with electrons in other atoms in entirely different ways. Carbon provides a familiar example of the changes that can result. Coal is carbon formed from plant debris, compacted and heated for millions of years a few kilometres below ground. But go 100 kilometres or so down, and the high temperature, along with pressures 30,000 to 50,000 times those at Earth's surface, transform carbon's bonding to make an apparently different substance: diamond.

 

"Occasionally, geological processes fortuitously bring diamonds closer to the surface, where they can be mined. Since the 1950s, however, researchers have been cutting out the billion-year geological middlemen. Large hydraulic presses weighing tens of tonnes now compress carbon to yield synthetic diamonds used in coatings, cutting tools and even jewellery. But even these pressures are tiny compared with those deep in Earth's interior.... For a more complete picture of the planet, we'd love to track what goes on in this high-pressure realm. 'Stuff is moving and reacting, causing fluxes in different elements such as carbon, and this has relevance for climate change over geological history and theories about the origin of life,' says geochemist Catherine McCammon of Bayreuth University in Germany.

 

"Diamond to the core

 

"With no direct access to such depths -- our deepest drilled hole, the Kola Superdeep Borehole, penetrates just 12 kilometres beneath the north-west tip of Russia -- simulating the pressures found there requires some cunning ruses. As anyone who has stepped on a polished wooden floor wearing high-heeled shoes knows, force concentrated into a small area produces very high pressures. A device known as an anvil cell takes advantage of this fact, producing the same effect as a monster hydraulic press by crushing tiny samples between two high-heel tips made of extremely hard materials. Tungsten carbide is one such material, capable of delivering pressures equivalent to those in Earth's upper mantle. Diamond tips go further, to pressures found in Earth's core. They are also transparent, allowing researchers to observe in real time what happens as materials are crushed.

 

"Even so, to really see what is going on at the atomic level requires special illumination: the intense beams of X-ray light produced at synchrotron accelerators such as the European Synchrotron Radiation Facility (ESRF) in Grenoble, France. McCammon and her colleagues recently placed their diamond anvil cell in the ESRF's beams to address the puzzle of Earth's core consistency. The core generates Earth's magnetic field, and is mostly made of iron. But the way seismic waves pass through it suggest the core has a consistency rather like tyre rubber -- which is not what pure iron looks like under pressure. When mixed with carbon graphite powder and compressed, however, the researchers found iron forms an entirely different crystalline phase that mimics this plasticity, suggesting Earth has a vast, previously unknown carbon reservoir (Nature Geoscience, vol 8, p.220). Similar experiments have also recently yielded new estimates for iron's melting temperature under pressure, leading to the conclusion that the temperature of Earth's inner core is 6000°C, some 1000 degrees hotter than previously thought.

 

"Iron's large number of orbiting electrons make it particularly difficult to model under pressure. Undaunted, researchers such as Loubeyre are moving on to even more complex elements, such as the rare earths. These materials are essential for technology from screens for smartphones to magnets for wind turbines, and the hope is that exploring high-pressure forms will allow us to better exploit their properties. This same motivation holds for simpler elements, too -- and it's here that the surprises have been greatest. Exert a pressure akin to those found in Earth's outer core, and sodium -- a soft, highly reactive metal at Earth's surface -- becomes transparent and something between a semiconductor and an insulator. Oxygen, meanwhile, turns into a solid metal at similar pressures, and if then cooled becomes a superconductor -- in other words, it conducts electricity with no resistance.

 

"The dramatic nature of these changes has caught many on the hop. 'There have been simple rules guiding this field, but it turns out these things were wrong,' says Loubeyre. 'We are seeing baffling changes in unit cell volumes and remarkable electrical properties that are highly promising for applications.' Perhaps the most promising is the simplest atom of all: hydrogen. This is the universe's most abundant element, consisting of just a single electron orbiting a single proton. It is a bit of a misfit in the periodic table, generally sitting uneasily above lithium and sodium at the top of metallic group 1.

 

"Calculations since the 1930s have indicated that high pressures would indeed turn hydrogen into a metal, squeezing the electron out of each proton's orbit and leaving them free to conduct. Not only that, but calculations suggested that the electrons' skittish interactions with the lattice of proton cores might at some point allow them to team up and pass through the solid hydrogen unimpaired -- hydrogen could be made a superconductor. That might even occur at room temperature and potentially persist even when the pressure is taken off, just as diamonds retain their structure at lower pressures.

 

"This would be a trillion-dollar transition. The highest temperature so far seen for a superconductor, a copper-based compound called a cuprate, is -140°C at ambient pressure, and -110°C at high pressures. A room-temperature superconductor could allow the transmission of energy over distance without loss at a much lower price, transforming the electricity grid and consigning the internal combustion engine to history. No one is sure at what pressure hydrogen's metallic and superconducting transitions might occur, although it seems likely that a metallic, although not superconducting, state makes up the core of Jupiter and other gas-giant planets. That's tough to replicate: the pressure at Jupiter's centre is 4000 gigapascals (GPa), more than 10 times that in Earth's inner core and 40 million times greater than at Earth's surface.

 

"In 2011 Mikhail Eremets and Ivan Troyan of the Max Planck Institute for Chemistry in Mainz, Germany, reported a metallic transition in hydrogen compressed to just 260 GPa in a diamond anvil cell (Nature Materials, vol 10, p.927). The claim was met with scepticism, and later analysis suggested they had probably found something subtly different: a poorly conducting semi-metal state (Physical Review B, vol 88, p.045125).

 

"Still, just last month Eremets and Troyan pulled off something close to the desired trick with hydrogen atoms in a slightly more complex chemical form. They compressed hydrogen sulphide -- that smelliest of gases, which gives off a strong whiff of rotten eggs -- to just 90 GPa and transformed it to a solid metal. Taken to 150 GPa, it seems to become a superconductor when cooled to just -70°C, the highest temperature ever recorded for a superconductor (Nature, DOI 10.1038/nature14964). This superconductor also seems to work by a conventional mechanism that has been understood for 50 years, in contrast to the still-mysterious workings of the cuprates.

 

"Pure hydrogen still remains the ultimate goal -- after all, says Patrick Bruno of the ESRF, the discovery of metallic hydrogen would probably be worth a Nobel prize. Besides a potential room-temperature superconductor, metallic hydrogen might form the basis of a revolutionary fuel technology: the molecular bonds of pure hydrogen are broken at high pressure, leaving a system that can store a huge amount of chemical energy. There are still high-pressure depths to plumb to get there. 'Recent work on sophisticated simulations cast doubts that there is any metallic state below 400 GPa -- the current edge for experimental studies,' says Eremets. Loubeyre and his colleagues are working with a two-stage anvil -- essentially a diamond crushing a diamond crushing something else -- that lets them achieve pressures of 600 GPa, and he is confident of results soon. 'Metallic hydrogen will probably be discovered in the next two to three years,' he says.

 

"Meanwhile new pressure records continue to be set -- most recently osmium, Earth's least compressible metal, crushed at 770 GPa. As we progress we are beginning to find out just how much the 99.9 per cent of chemistry we don't see differs from the 0.1 per cent we do. Our techniques currently limit us to observing the properties of small samples of high-pressure materials, but the hope is that better synchrotrons, for example, will allow us to observe and perhaps even mimic the chemical reactions between different compounds that must go on deep beneath our feet.

 

"That truly would be an eye-opener. Chemists already know and routinely exploit the transformations in chemical reactivity that even relatively small pressure increases bring. Molecular nitrogen in the atmosphere, for example, is a thankfully unreactive gas. But up the pressure 200-fold, and it readily reacts to make the fertiliser ammonia -- the basis of the Haber-Bosch reaction that, by transforming agricultural productivity, has fed many a hungry mouth since the early 20th century. With such successes in mind, the pressure's on to discover more." [Quoted from here; accessed 15/09/2015. Quotation marks altered to conform with the conventions adopted at this site. Some paragraphs merged to save space. Two links added.]

 

Should We Ditch The Current Theory Of The Solar System?

 

March 2015: This from the BBC:

 

"Lucky Earth survived cosmic pinball

 

 

"Rogue alien planets are forcing astronomers to rethink the birth of our Solar System. What's emerging is a tale of hellfire, chaos and planetary pinball -- and it's a miracle our Earth survived. Hunting for alien planets is big business. Since the first exoplanet was discovered in 1995, astronomers around the world have been searching for those elusive Earth-like planets that could harbour life. The tally of planets found is staggering. So far, more than 1,800 confirmed planets have been discovered orbiting around other stars in our galaxy (the latest figure from Nasa is 1,816 planets around 1,117 stars). Among them, are a few rocky planets in the magical 'Goldilocks' zone where water can remain in the liquid state, and life could evolve.

 

"It's no surprise to astronomers that these planets exist. But what has come as a shock is that many of these exoplanets seem to break all the rules. Dr Christopher Watson, from Queen's University, Belfast, is at the forefront of research into these bizarre new worlds. 'They're very strange,' he told the BBC's Horizon programme. 'These are nothing like our Solar System, and in some cases, I think really science fact can be a lot weirder than science fiction.'

 

"Two hundred light-years away from Earth is a strange world called Kepler 16b. It is a planet with two suns, much Luke Skywalker's home planet -- Tatooine. Then there is Kepler 78b, a rocky planet about the size of Earth, but so close to its star that it completes an orbit once every eight-and-a-half hours. As a result, it is just a seething ball of lava.  Most baffling of all have been the 'Hot Jupiters' -- giant gas planets in impossible orbits close to their star. Watson, along with most of the astronomical community, was initially baffled: 'They were right up against their host star and it's amazing. They really shouldn't be there.'

 

"The trouble with these rogue planets is that they seem to break the laws of physics. It's simply not possible for them to form that close to a star. But, if you eliminate the impossible, then whatever remains, however improbable, must be the truth. The startling conclusion reached by Dr Watson and others is that the planets formed further away, and then migrated in to where we see them today. They changed orbit. This idea that planets could change orbit, moving closer or further away from their star, turned astronomy on its head and led to one of the biggest rethinks since the time of Copernicus and Galileo. It led astronomers like Dr Kevin Walsh, from the Southwest Research Institute in Boulder, Colorado, to question everything about the birth and evolution of our own Solar System.

 

"'When we started finding planets in places we thought you could never possibly form a planet, we had to go back to the drawing board and say, "wow, planets can move, planets can really move. Maybe that happened here",' he says.

 

"Since the time of Galileo, we have assumed that the planets in our Solar System follow stable, fixed orbits. We assumed that the planets were formed where we find them now -- from the left-over dust and gas when the Sun burst into life. We assumed that our Solar System has, for four-and-a-half billion years, been a peaceful haven, stable for sufficient time to enable life to evolve on Earth. And yet there are some nagging mysteries about our own system of planets that have never been explained. Mars, for example, is much smaller than we would expect; the asteroid belt is divided into two neat bands -- an inner band of rocky material, and an outer band of icy lumps.

 

"New narrative

 

"No-one ever found a satisfactory explanation for these mysteries, and yet they are clues to a turbulent history that astronomers are beginning to uncover. Since the discovery of migrating exoplanets, planetary scientists have proposed new models for the formation of our Solar System. They suggest that, far from being a peaceful and stable system with fixed orbits, our Solar System underwent periods of chaos, with Jupiter, the big bully of the Solar System, calling the shots.

 

"'The Solar System is not this nice, safe, quiescent place, but can go through periods of intense violence,' says Dr Hal Levison of the Southwest Research Institute in Boulder. He believes it's time to re-examine the evidence with fresh eyes: 'Sometimes the blood spattered on the wall can tell you more about what happened than the body lying on the floor.' According to Dr Walsh, Jupiter may have undertaken a wild journey through the Solar System, spreading havoc, stunting the growth of Mars and scattering everything in its path.

 

"'Dice roll'

 

"With a planet the size of Jupiter travelling freely through the system of planets, the outcome would have been far from certain. 'The Solar System could have done a lot of different things. It could have evolved in a lot of different ways. We could have ended up with our Jupiter right next to the Sun,' he explains. The latest evidence suggests our Solar System underwent a period of chaotic upheaval, before settling down to the stable system we see today. Our own home, planet Earth -- in the perfect place for life to evolve -- was lucky to survive.

 

"Dr Walsh comments: 'Getting an Earth where we have our Earth today was not a given when this whole Solar System started.' So, astronomers are left with the question -- how common is a solar system like ours? There may be plenty of planets out there. But getting a stable, ordered arrangement like our own Solar System, could just be a lucky roll of the dice.

 

"You can watch Horizon: Secrets of the Solar System on BBC2 on Tuesday 3 March at 21:00." [Quoted from here; accessed 08/03/2015. Some links added; several paragraphs merged to save space. Quotation marks altered to conform with the conventions adopted at this site. The entire programme can be accessed here.]

 

The programme itself featured quotes from scientists (and the editors) like the following: "If we want to understand the birth of our Solar System, we're going to need a brand new model", "There's some mysteries when we look around the Solar System, where the theories really don't match what we see", "We started finding planets in places we'd never thought you could possibly form a planet. We had to go back to the drawing board. It's changed the way we look at almost every process in the Solar System", and "Strange new worlds that break all the rules have made astronomers question everything."

 

Add to the above the following article about "Wandering Jupiter":  

 

"Wandering Jupiter swept away super-Earths, creating our unusual Solar System

 

"Posted on 25 March 2015 by Astronomy Now

 

"Jupiter may have swept through the early Solar System like a wrecking ball, destroying a first generation of inner planets before retreating into its current orbit, according to a new study published March 23rd in Proceedings of the National Academy of Sciences. The findings help explain why our Solar System is so different from the hundreds of other planetary systems that astronomers have discovered in recent years.

 

"'Now that we can look at our own Solar System in the context of all these other planetary systems, one of the most interesting features is the absence of planets inside the orbit of Mercury,' said Gregory Laughlin, professor and chair of astronomy and astrophysics at UC Santa Cruz and coauthor of the paper. 'The standard issue planetary system in our galaxy seems to be a set of super-Earths with alarmingly short orbital periods. Our Solar System is looking increasingly like an oddball.' The new paper explains not only the 'gaping hole' in our inner Solar System, he said, but also certain characteristics of Earth and the other inner rocky planets, which would have formed later than the outer planets from a depleted supply of planet-forming material.

 

"Laughlin and coauthor Konstantin Batygin explored the implications of a leading scenario for the formation of Jupiter and Saturn. In that scenario, proposed by another team of astronomers in 2011 and known as the 'Grand Tack,' Jupiter first migrated inward toward the Sun until the formation of Saturn caused it to reverse course and migrate outward to its current position. Batygin, who first worked with Laughlin as an undergraduate at UC Santa Cruz and is now an assistant professor of planetary science at the California Institute of Technology, performed numerical calculations to see what would happen if a set of rocky planets with close-in orbits had formed prior to Jupiter's inward migration.

 

"At that time, it's plausible that rocky planets with deep atmospheres would have been forming close to the Sun from a dense disc of gas and dust, on their way to becoming typical 'super-Earths' like so many of the exoplanets astronomers have found around other stars. As Jupiter moved inward, however, gravitational perturbations from the giant planet would have swept the inner planets (and smaller planetesimals and asteroids) into close-knit, overlapping orbits, setting off a series of collisions that smashed all the nascent planets into pieces. 'It's the same thing we worry about if satellites were to be destroyed in low-Earth orbit. Their fragments would start smashing into other satellites and you'd risk a chain reaction of collisions. Our work indicates that Jupiter would have created just such a collisional cascade in the inner Solar System,' Laughlin said.

 

"The resulting debris would then have spiralled into the Sun under the influence of a strong 'headwind' from the dense gas still swirling around the Sun. The ingoing avalanche would have destroyed any newly-formed super-Earths by driving them into the Sun. A second generation of inner planets would have formed later from the depleted material that was left behind, consistent with evidence that our Solar System's inner planets are younger than the outer planets. The resulting inner planets -- Mercury, Venus, Earth, and Mars -- are also less massive and have much thinner atmospheres than would otherwise be expected, Laughlin said. 'One of the predictions of our theory is that truly Earth-like planets, with solid surfaces and modest atmospheric pressures, are rare,' he said.

 

"Planet hunters have detected well over a thousand exoplanets orbiting stars in our galaxy, including nearly 500 systems with multiple planets. What has emerged from these observations as the 'typical' planetary system is one consisting of a few planets with masses several times larger than the Earth's (called super-Earths) orbiting much closer to their host star than Mercury is to the Sun. In systems with giant planets similar to Jupiter, they also tend to be much closer to their host stars than the giant planets in our Solar System. The rocky inner planets of our Solar System, with relatively low masses and thin atmospheres, may turn out to be fairly anomalous.

 

"According to Laughlin, the formation of giant planets like Jupiter is somewhat rare, but when it occurs the giant planet usually migrates inward and ends up at an orbital distance similar to Earth's. Only the formation of Saturn in our own Solar System pulled Jupiter back out and allowed Mercury, Venus, Earth, and Mars to form. Therefore, another prediction of the paper is that systems with giant planets at orbital periods of more than about 100 days would be unlikely to host multiple close-in planets, Laughlin said.

 

"'This kind of theory, where first this happened and then that happened, is almost always wrong, so I was initially sceptical,' he said. 'But it actually involves generic processes that have been extensively studied by other researchers. There is a lot of evidence that supports the idea of Jupiter's inward and then outward migration. Our work looks at the consequences of that. Jupiter's 'Grand Tack' may well have been a 'Grand Attack' on the original inner Solar System." [Quoted from here; accessed 06/08/2015; quotation marks altered to conform with the conventions adopted at this site. Several paragraphs merged to save space.]

 

 Cosmological Principle Ready For The Scrapheap?

 

November 2015: The following article appeared in the New Scientist; it shows that the centuries old Copernican Cosmological Principle is not only threatened by recent  observations, it has also served as a "form of representation". Notice how physicists will consider certifiably harebrained ideas in order to protect this Principle, allowing them to continue using it as an inferential, or explanatory device (i.e., as a "paradigm") -- and how this also puts serious pressure on Einstein's Theory of Relativity:

 

"A giant hole in the web of galaxies that fills the cosmos. A colossal string of quasars billions of light years across. A ring made out of hugely energetic bursts of radiation that spans 6 per cent of the visible universe. As our observations of the cosmos come into ever sharper focus, astronomers are beginning to identify structures bigger than any seen before. There's only one problem: none of them should be there.

 

"Ever since Copernicus proposed his revolutionary idea that Earth's place among the stars is nothing special, astronomers have regarded it as fundamental. The cosmological principle it has evolved into goes a step further, stating that nowhere in the universe is special. You're allowed to have patches of individuality on the level of solar systems, galaxies and galaxy clusters, of course, but zoom out far enough and the universe should exhibit a drab homogeneity. No vast galactic walls or bald spots, and no huge structures. Small wonder that the spate of recent findings has got cosmologists hot under the collar. But the solution could prove equally controversial. One researcher claims these massive structures are illusions projected from another dimension, the first tantalising evidence of realities beyond our own. If he is right, and these behemoths don't exist as physical objects within our universe, then the cosmological principle might still be safe.

 

"The concept of favoured regions in the universe is anathema to modern cosmology. 'All our thinking since the Renaissance has been working against that idea,' says Seshadri Nadathur, a cosmologist at the University of Portsmouth in the UK. It also makes using Einstein's general theory of relativity to understand gravity's role in the evolution of our universe an even more fiendish task than it already is. 'Einstein's equations are much easier to solve if you assume a universe that's almost homogeneous,' says Nadathur. But, at the moment, the cosmological principle is just that -- an assumption. There is no concrete evidence that it is true, and the evidence we do have seems increasingly against it.

 

"Take that giant hole in the universe -- a void almost 2 billion light years wide, according to its co-discoverer, András Kovács of the Institute for High Energy Physics in Barcelona, Spain. 'There are 10,000 fewer galaxies in that part of the sky compared with the universal average,' says Kovács. Based on the latest data, astronomers believe that the cosmological principle must apply on scales of roughly a billion light years, with the average amount of material in any given volume more or less the same. A big empty patch almost double the size of the cut-off stands out like a sore thumb. Kovács and his team call this vast expanse a supervoid, and believe it might explain away the giant cold spot in the cosmic microwave background, an observation that has been puzzling astronomers for over a decade....

 

"And the supervoid isn't the half of it. As far back as 2012, a team led by Roger Clowes at the University of Central Lancashire, UK, claimed to have found an enormous structure strung out over 4 billion light years -- more than twice the size of the supervoid. 'We thought "what is that!?" It was obviously something very unusual,' says Clowes. Yet this time it wasn't an empty patch of space, but a particularly crowded one. Known as the Huge Large Quasar Group, it contains 73 quasars -- the bright, active central regions of very distant galaxies. Astronomers have known since the early 1980s that quasars tend to huddle together, but never before had a grouping been found on such a large scale.

 

"Then earlier this year a team of Hungarian astronomers uncovered a colossal group of gamma-ray bursts (GRBs) -- highly energetic, short-lived flashes of energy erupting from distant galaxies. The galaxies emitting these GRBs appear to form a ring a whopping 5.6 billion light years across -- 6 per cent of the size of the entire visible universe. 'We really didn't expect to find something this big,' says Lajos Balázs from the Konkoly Observatory in Budapest, Hungary, who led the study. Its size makes it five times larger than the typical scale at which the cosmological principle tells us that homogeneity should kick in.

 

"So fundamental is the cosmological principle to our understanding of the universe that such apparent violations make astronomers and cosmologists deeply uncomfortable, even those who discovered them in the first place. When it comes to the intense flashes of light that make up the GRB ring, for instance, there's a possibility they might be surrounded by other galaxies, currently shining less brightly because of an absence of GRBs. It's like being in a darkened room in which light bulbs are evenly distributed: if only a few are illuminated when you look into the room, you're likely to draw the wrong conclusions about how they are arranged. 'It doesn’t necessarily contradict the cosmological principle,' says Balázs.

 

"Rise of the giant-killers

 

"The huge large quasar group is also the subject of intense debate. 'I don't think it's really a structure at all,' says Nadathur. In 2013, he published a paper studying the algorithm Clowes and his team used to analyse their data, calculating the probability that a random distribution of quasars would also yield an apparent structure. 'The chances of seeing a pattern like the one they see, even if there is nothing there, is quite high,' he says. But the giant might not be dead just yet. Clowes's PhD student, Gabriel Marinello, is working on a paper countering Nadathur's claims, which he describes as 'conservative and unrealistic'. He argues that instead of modelling a random distribution, Nadathur should have included the fact that quasars -- just like other galaxies -- are known to huddle together on scales of around 300 million light years.

 

"As well as the quasar group, Nadathur thinks the supervoid could also be reconciled with the cosmological principle. 'The principle is not saying that any one place cannot fluctuate from the norm, just that on average the large-scale universe must be homogeneous,' says Nadathur. In short, the probability of finding objects like the supervoid is not zero. There just can't be too many of them. But Rainer Dick, a theoretical physicist at the University of Saskatchewan, Canada, believes such attempts to brush these cosmic megastructures aside are misguided. In fact, he says they should be embraced as our best bet of keeping the cosmological principle alive. All we have to do is accept that they don't actually exist. Instead, they represent the first evidence of other dimensions intruding into our own, leaving dirty footprints behind on our otherwise smooth and homogeneous cosmic background.

 

"It seems a breathtakingly audacious proposal -- but it builds on a solid foundation of theoretical work. For one thing, conjuring up other dimensions beyond our own is nothing new. For decades, many theorists have regarded the existence of extra dimensions as our best hope of reconciling Einstein's general relativity with that other bastion of 20th century physics: quantum theory. A marriage between these two seemingly disparate concepts, one dealing with the very large and the other with the very small, would yield what is often called a theory of everything, a one-size-fits-all framework capable of describing the universe in its entirety.

 

"One popular candidate is M-theory, an extension of string theory that famously suggests we live in an 11 dimensional universe, with the other seven dimensions curled up so tightly as to drop out of sight. It's an elegant and mathematically appealing framework with a number of influential supporters. But it has one major failing: the lack of solid predictions offering opportunities to verify it. Dick's work on a generalisation of string theory known as brane theory might provide just such a prediction, and resolve the cosmological principle dilemma to boot.

 

"At the heart of brane theory is the idea that what we perceive as our universe is a single four dimensional membrane floating in a sea of similar branes spanning multiple extra dimensions. Such an idea is not inconsistent with our established theory of gravity, says Dick, as 'you can add infinitely large extra dimensions and still get back general relativity'. Although the other branes occupy extra dimensions, and so would be impossible to observe directly, the theory suggests we might just be able to spot the effects of a neighbouring brane overlapping with ours.

 

"So how does this help with the problem of the cosmological principle? Well, in order to measure our distance to far-off objects, astronomers exploit an effect known as redshift. They break down the light from the object using a spectrometer -- a fancy version of a prism -- to reveal bands known as spectral lines. Any object moving away from us because of the universe's ongoing expansion will have its light stretched out to longer, redder wavelengths and the lines will appear shifted towards the red end of the spectrum. The further away the object, the faster it will appear to recede and the more the lines will shift. If astronomers see many objects all exhibiting the same redshift, they will interpret that as some form of structure, just like the GRB ring or the huge quasar group.

 

"Except, looking into a region where another brane is overlapping with our own might skew our redshift measurements. Under these conditions, photons in one brane would exert a force on charged particles in another -- a phenomenon Dick calls brane crosstalk. 'This would change the distance between the energy levels within hydrogen atoms in the overlap region,' he says. Electrons moving between these energy levels either emit or absorb photons, producing the spectral lines we rely on for working out their distance from Earth.

 

"But if brane crosstalk were to narrow the energy-level gap, this would produce photons of a slightly longer wavelength -- a redshift that has nothing to do with the expansion of the universe. If you fail to take this into account, and assume the overall redshift you measure is solely the result of distance, then you will systematically overestimate how far away an object in the overlap region actually is, with large swathes of empty space visible in its true location....

 

"If such a model held true, areas of brane overlap would produce an apparent pile-up of objects at one redshift and a distinct lack of objects at another -- an optical illusion that would make a homogeneous universe appear to contain massive structures and enormous voids. In a stroke, this would explain the origins of the quasar group and the GRB ring as well as the supervoid, says Dick. 'These structures match the potential signal of brane crosstalk.'

 

"Of course, it's hardly an open-and-shut case. 'There are many assumptions that one must accept in order for this to happen, and some of them may just be taking things a bit too far,' says Moataz Emam from the State University of New York College at Cortland. Emam also warns that some of the assumptions about gravity that Dick's theory relies on have been severely criticised in the past, not least by string theorists who have had difficulty reconciling them with their calculations. 'But his model is certainly testable,' he says.

 

"Emam suggests that the necessary evidence could be found by observing parts of the sky where high density regions coexist next to apparent barren patches. Provided the discrepancy in redshift measurements is identical in all cases, it might well suggest that our brane is overlapping with another. With the help of the Sloan Digital Sky Survey (SDSS) -- the most detailed three-dimensional map of the universe ever made -- Dick is now planning to scour the databases for redshift data that could support his theory. 'That really would be compelling evidence that our universe is not alone,' he says. Such a discovery would not only explain away some of the most perplexing observations in astronomy, but give the abstract field of string theory a tantalising experimental foundation.

 

"But his quest to cut the universe's largest objects down to size might lead to new monsters arising in their place. The discovery of branes beyond our own, for instance, would pose a serious challenge to humanity's fragile sense of its place in the cosmos, and make a nonsense of our concept of cosmic homogeneity. In a vast multiverse of interacting membranes, the cosmological principle might not be worth saving after all." [Quoted from here; accessed 13/11/2015. Quotation marks altered to conform with the conventions adopted at this site. Bold emphases and some links added. Several paragraphs merged to save space.]

 

Cosmic Expansion In Crisis?

 

June 2016: We read this in the New Scientist:

 

"The Cosmic Expansion Crisis

 

"We must be missing something. The universe is expanding 9 per cent faster than it should be. Either our best measurements are wrong, or a glimmer of new physics is peeking through the cracks of modern cosmology.

 

"If that's the case, some lightweight, near-light-speed particles may be missing from our picture of the universe shortly after the big bang. But we might be in luck. Particle physicists have already spent over a decade chasing something that fits the bill: ghostly neutrinos unlike the three already known. For a cosmological quandary, the issue isn't that complicated: two ways of measuring how quickly the universe is flying apart are coming up with increasingly different numbers. The first looks at dimples in the cosmic microwave background, a glow left behind by the hot, soupy universe just a few hundred thousand years after the big bang. The size of these fluctuations let us calculate how quickly the universe was expanding when it began some 13.7 billion years ago.

 

"The other method measures how distant galaxies appear to recede from us as the universe expands -- which led to the discovery of dark energy (sic -- RL!), a mysterious outward pressure pushing the universe apart. The trouble comes when we compare the two estimates. 'They don't agree,' says Adam Riess of the Space Telescope Science Institute in Baltimore, Maryland, one of the recipients of the 2011 Nobel prize in physics for dark energy's discovery and an author of a new paper pointing out the tension (arxiv.org/abs/1604.01424).

 

"So what are we missing? Our picture of what the universe is made of can't change much, since it agrees so well with observations. These show that the history of the universe has been a balancing act between just a few ingredients, which competed for dominance as the universe stretched and changed. This model of the cosmos has been the mainstream idea for years, but it's showing signs of strain. 'We've given these really smart kids, the young cosmologists, what we thought was a pretty good toy, and now they're trying to break it,' says Michael Turner at the University of Chicago. 'Maybe they have.' Would tweaking the ingredients themselves help make sense of the difference?

 

"One possibility is that dark energy is a little stronger than we thought. Or it could have ramped up over time, giving expansion a bigger push. That's not a very appealing theory, though, says Avi Loeb of Harvard University. The measured strength of dark energy is already a 'big headache', he says. Letting it vary in time would add another, perhaps unjustifiable, wrinkle. 'That would be twice as much pain,' Loeb says.

 

"But the deeper problem with darkening dark energy is that it doesn't do enough to bridge the gap between the ancient and modern measurements. Fiddling with dark energy enough to help would put it into disagreement with other observations. 'You can only do this so much,' Riess says. The easiest solution, says Riess, is dark radiation: small, unknown particles similar to neutrinos, moving close to the speed of light around the beginning of time. This is the period when effects from undiscovered particles would have been felt most strongly.... In our current understanding, as the universe expanded, dark energy filled the space formed, with matter becoming more dilute. Through a war of attrition, the outward-pushing dark energy came to dominate matter.

 

"Weaker brakes

 

"But if some mass was trapped in light, fast-moving particles, dark energy would have won even more quickly. That's because as the universe expanded, stretching space would have shifted the particles to lower energies, weakening their pull. Adding this ingredient into the standard account of the early universe could bring the modern and primitive expansion rates back in line -- not because the foot on the accelerator was heavier than expected, but because back then the brakes were a little weaker.

 

"There may be a chance that we have already glimpsed a dark radiation particle. For years, we have seen hints of so-called 'sterile' neutrinos, which would interact with gravity and the three known neutrinos, but little else. Vexingly, measurements rule out the simplest version of sterile neutrinos as our missing particle. But there may be room for something stranger still.

 

"'Let's say these neutrinos are not truly sterile,' says Alexander Friedland at the Stanford Linear Accelerator in California. 'They have their own interactions, and they are part of some hidden sector -- some world which exists right under our noses but interacts with our world extremely weakly.' If so, such neutrinos could be the missing ingredient. And through neutrino experiments and ever-better studies of the early universe, we might know within the next decade if a hidden sector of particles offers a way out.

 

"'This is where we are,' Friedland says. 'There are hints, and they will be tested.' [New Scientist, 11/06/2016, pp.8-9. Quoted from here; accessed 12/06/2016. Quotation marks altered to conform with the conventions adopted at this site. Several paragraphs merged to save space. The on-line article and the published version have different titles. Bold emphases and one link added. Several paragraphs merged to save space.]

 

It seems that when cosmologists encounter a problem they just invent another particle -- a bit like astronomers invent a new planet whenever they observe an unexpected wobble in another planet's orbit (which does not always turn out to be a wise move), and bit like theoretical physicists help themselves to a new 'dimension' whenever they encounter problems in M-theory.

 

More to follow...

 

Latest Update: 16/05/17

 

Word Count: 38,370

 

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