13 more things that don’t make sense
2 September 2009
13 more things: The axis of evil
WHAT would you do if you found a mysterious and controversial pattern in the radiation left over from the big bang? In 2005, Kate Land and João Magueijo at Imperial College London faced just such a conundrum. What they did next was a PR master stroke: they called their discovery the cosmic “axis of evil“.
What exactly had they seen? Instead of finding hot and cold spots randomly spattered across the sky as they expected, the pair’s analysis showed that the spots in the cosmic microwave background (CMB) appeared to be aligned in one particular direction through space.
The apparent alignment is “evil” because it undermines what we thought we knew about the early universe. Modern cosmology is built on the assumption that the universe is essentially the same in whichever direction we look. If the cosmic radiation has a preferred direction, that assumption may have to go – along with our best theories about cosmic history.
This disaster might be averted if we can show that the axis arises from some oddity in the way our telescopes and satellites observe the radiation. A nearby supercluster of galaxies could also save the day: its gravitational pull might be enough to distort the radiation into the anomalous form seen.
Nobody knows for sure. We are dealing with the limits of our capabilities, says Michael Longo of the University of Michigan in Ann Arbor. “All observations beyond our galaxy are obscured by the disc of the Milky Way,” he points out, so we need to be careful how we interpret them.
The European Space Agency’s recently launched Planck space telescope might settle the issue when it makes the most sensitive maps yet of the CMB. Until then, the axis of evil continues to terrorise us.
13 more things: Dark flow
The galaxy cluster 1E 0657-56, 3.8 billion light-years away, is one of hundreds that appear to be carried along by a mysterious cosmic flow
WE CANNOT see what lies beyond the visible horizon of our universe, simply because light emitted beyond that horizon has not had time to reach us. Despite this out-of-sightness, we’ve always assumed that space is filled with the same stuff wherever you go in the universe.
So a recent finding by Sasha Kashlinsky at NASA’s Goddard Space Flight Center in Greenbelt, Maryland, does not make sense. His team has found a group of galaxy clusters moving at an extraordinary speed towards a small patch of sky between the constellations of Centaurus and Vela. Kashlinsky calls it the “dark flow”, in tribute to those other cosmic mysteries dark matter and dark energy (New Scientist, 24 January, p 50).
There is no obvious reason why the clusters should be moving at such breakneck speeds, unless they are experiencing an unusually strong pull from something beyond the visible horizon. But what? The most obvious answer is that there is something big out there, far bigger than anything in our known universe. Such a behemoth would impose a kind of “tilt” on the universe, causing matter to move in one particular direction – as observations of the dark flow suggest.
“Something outside the visible universe appears to be pulling on galaxy clusters. But what?”
If such cosmic megastructures do exist, though, they merely replace one mystery with another. One of the foundation stones of cosmology is the Copernican principle, which says that there is nothing special about our region of the universe. So if there are megastructures beyond our horizon, there should be megastructures in our patch, too. We haven’t seen any.
There are also suggestions that the pull might be from another universe altogether. That would be good news for proponents of eternal inflation theory, which suggests that the universe should actually be composed of “mini-universes” that have bubbled off from one another.
Kashlinsky is preparing papers with further results. He says observations point the finger at megastructures beyond the horizon.
13 more things: Prehistoric hothouse
Tens of millions of years ago, the average temperature at the poles was 15 or 20 °C
THE Eocene ran from 56 million to 34 million years ago. Geological evidence from the early and middle part of this period offers troubling news: the average temperature in the tropics at this time could have been as high as 40°C while the poles were at temperatures of 15 or 20°C. None of our climate models accounts for how this “Eocene hothouse” might have arisen (New Scientist, 21 June 2008, p 34).
Whichever way you look at the Eocene enigma, it is bad news for life on Earth. For a start, any tweaks we make to our climate models to account for it will produce scarier predictions of warming. Secondly, it suggests that there is no feedback mechanism that will stabilise a warming world against runaway climate change. And third, there is geological evidence for plant extinctions in the Eocene.
If the modern Earth goes the same way and plants in the tropics start dying, that will provide yet another way for atmospheric carbon dioxide levels to rise faster. The Eocene hothouse anomaly suggests that our worst-case scenario is probably optimistic to say the least.
13 more things: Fly-by anomalies
RETIRED NASA engineer John Anderson will be watching keenly on 13 November as the European Space Agency’s Rosetta spacecraft flies by Earth for the third and final time on its way to comet 67P/Churyumov-Gerasimenko.
Such fly-bys give spacecraft a whip-crack of extra speed on their tour through the solar system. By using the gravitational fields of planets or moons, you can save fuel and travel much further through the solar system than would otherwise be possible. But this trick has had an unexpected effect (New Scientist, 20 September 2008, p 38).
In December 1990, for example, NASA’s Galileo spacecraft slingshotted around the Earth on its roundabout route to Jupiter. As the probe raced away from Earth, it was travelling 3.9 millimetres per second faster than it should have been, according to NASA’s calculations. The biggest such discrepancy recorded, in 1998, affected NASA’s NEAR Shoemaker spacecraft, whose speed was boosted by an additional 13.5 millimetres per second. Rosetta has already had a boost: in 2005 it sped up by about 1.8 millimetres per second more than expected as it slingshotted around Earth.
Nothing in known physics predicts this acceleration. Enter Anderson: he put all the data together and came up with an empirical formula that relates the probes’ incoming and outgoing trajectory angles and Earth’s rotational velocity to the extra acceleration experienced by the spacecraft as they swing by us. He found that the smallest anomalies arise when the incoming and outgoing trajectory are symmetrical with respect to Earth’s equator. In a bizarre twist, though, the formula also involves the speed of light. So what, ultimately, is the physics behind it?
There is no explanation from standard, accepted physics, but a variety of exotic explanations have been proposed. These incorporate dark matter, modifications to relativity, imbalances in the Earth’s gravitational field or something unknown to do with inertia or the nature of light. “Of these ideas, the least controversial is that the anomaly has something to do with dark matter bound to the Earth,” says Michael Nieto of Los Alamos National Laboratory, who has been working with Anderson on the anomaly.
13 more things: Hybrid life
These sea squirts were created when two evolutionary lineages fused
LOOK at the genome of a sea squirt and you’ll get a nasty surprise. Half of its genes have a straightforward evolutionary history. In fairness, so does the other half. Trouble is, the two histories are completely different. It seems that sea squirts do not, as we had thought, sit among the chordates, on the same evolutionary line as humans and other vertebrates. Instead, they are the result of what happens when you fuse an ancient chordate with the ancestor of a sea urchin.
The fusion of two distinct evolutionary lines is not supposed to work. According to received biological wisdom, any chimeras that result are meant to be evolutionary dead ends. Not for the first time, received wisdom appears to be wrong (New Scientist, 16 June 2007, p 48).
“There was a view that hybridisation was bad, and ‘pure’ species were good,” says James Mallet of University College London. The truth is, hybridisation is like mutation – mostly it’s bad, but occasionally it throws out something that meets a need. “Natural selection can use whatever inherited variation comes its way,” Mallet says.
Biologists are now coming round to the idea that much of nature is not a product of neat family lines, but a messy mass of cross links. That may be how, for instance, genetic instructions can turn something like a caterpillar into something completely different: a butterfly.
Such metamorphosis is particularly prevalent in marine life, perhaps because fertilisation takes place in an environment where sperm can sometimes be carried to the “wrong” egg. With so many different creatures leaving eggs lying around waiting to be fertilised, perhaps it is not surprising that an occasional misfertilisation takes hold and produces something totally unexpected.
The classic case is the starfish Luidia sarsi. It starts out as a small larva with an even smaller starfish inside. Eventually, the starfish moves to the outside of the larva. Then they go their separate ways. What started as one rather odd organism continues and ends life as two.
So, how widespread is this new biological mess? We know that probably at least 10 per cent of plant species were formed by some kind of hybridisation. The jury is still out on how important the process is in “higher” species. “We are only beginning to scratch the surface,” says Mallet.
13 more things: Morgellons disease
Morgellons disease is unpleasant and debilitating; that is, if it exists
IF YOU have fatigue, skin lesions, aches and pains and a sensation that insects are crawling around under your skin, you most probably have Morgellons disease. Be warned though, that it may actually not exist. Whether or not Morgellons is a real disease, no one knows (New Scientist, 15 September 2007, p 46).
Something like the symptoms described above, supplemented by the appearance of strange fibres or filaments growing on or just beneath the skin, was reported by the 17th-century physician Thomas Browne. There were no other reported cases, and the disease seemed to disappear. Then, in 2002, the mother of a child with a skin ailment championed its comeback. Her child, she insisted, had Morgellons.
Delve into the medical literature, though, and Morgellons disease is frequently described as “unexplained dermopathy” or “delusional parasitosis” – a psychiatric illness that results in people mistakenly believing their skin to be infested with parasites.
“Are Morgellons sufferers under the mistaken belief that their skin is infested with parasites?”
In the internet age, such provocative delusions can spread easily, according to a letter published this year in the journal Psychosomatics (vol 50, p 90). Morgellons is an internet meme, say Andrew Lustig and his colleagues at the Centre for Addiction and Mental Health in Toronto, Canada. “With widespread reports dating back only about three years, Morgellons has seen explosive growth for a concept dormant for more than 300 years,” they say.
We may soon find out more. The US Centers for Disease Control and Prevention (CDC) is in the middle of a large, systematic study into Morgellons. The study aims to determine whether there is actually a physiological basis to the disease. The CDC is keeping an open mind on Morgellons, says Michele Pearson, who is leading the study. “CDC has approached this as an unexplained condition,” she says.
13 more things: The Bloop
The Bloop signal sounds like it was made by an animal, but nobody knows what could have done it
IN THE summer of 1997, an array of underwater microphones, or hydrophones, owned by the US government picked up a strange sound. For a minute, it rose rapidly in frequency; then it disappeared. The hydrophones, a relic of cold-war submarine tracking, picked up this signal again and again during those summer months, then it was never heard again. No one knows what made the sound, now known as “The Bloop” (hear it at http://www.thebloop.notlong.com).
It’s not the only mysterious sound heard in the ocean. In May 1997, hydrophones picked up the “Slowdown” sound. Over the course of about 7 minutes, it slowly dropped in pitch, rather like the sound of an aeroplane flying past (www.theslowdown.notlong.com). Its origin has been only loosely pinned down: it seems to have originated from somewhere off the west coast of South America, and could be heard from 2000 kilometres away.
So what’s behind the strange noises? The Bloop sounds like it might have been created by an animal, but it is far louder than any whale song, so a marine creature that made it would either be bigger than any whale, or a much more efficient producer of sound. The most popular speculation about Slowdown is that it was caused by the break-up of Antarctic ice – which means it might give an indication of climate change.
There is still no consensus, however, and these two mysteries are just a drop in the ocean, according to Sharon Nieukirk of the US National Oceanic and Atmospheric Administration. “We have hydrophones in the Atlantic, the Arctic, off Greenland, in the Bering Sea and in the Antarctic now, and I am constantly amazed at the variety of sounds coming from the sea,” she says. “There are hundreds of mystery sounds.” (Hear more at http://www.oceansounds.notlong.com.)
13 more things: Antimatter mystery
THE big bang should have created matter and antimatter in equal amounts, or so our best theories have it. If that were truly the case, though, then the universe would have disappeared in a big puff of self-annihilation almost as soon as it began. The fact that we are here to ponder it tells us something is wrong with this picture (New Scientist, 12 April 2008, p 26). The question is: what?
Experiments in accelerators now tell us that for every 10 billion antiprotons present in the early universe, there were 10-billion-and-one protons. The same tiny imbalance applied to other particles, such as electrons, too. At some point in cosmic history, matter and antimatter met and annihilated. Left behind, those extra particles eventually came together and formed the matter-filled universe we know today. So what created that initial imbalance?
The short answer is that we don’t know. One possibility is that antimatter is lurking out there at distant points around the cosmos. That’s unlikely, though.
A better idea springs from the weak force, which governs certain nuclear processes, including radioactive beta decay. In 1964, physicists found that the weak force is not quite symmetrical in its dealings with matter and antimatter, resulting in something known as CP violation. This has led particle physicists to suggest that the laws of physics are lopsided. The trouble is that the standard model of particle physics says they aren’t lopsided enough. “There is not enough CP violation to do the job,” says Frank Close at the University of Oxford.
Other ideas to explain the imbalance of matter and antimatter in the infant universe include a hypothetical particle called the majoron, which is thought to have created neutrinos and antineutrinos, but not in equal amounts. That could eventually have led to an imbalance between matter and antimatter. “If we find majorons at the Large Hadron Collider at CERN,” says Close, “then we could hope to study their decays.” This would help us discover if they fit the bill.
13 more things: The lithium problem
The universe only contains a third as much lithium as it’s supposed to
OUR best theories of the early universe also tell us which atoms should have been forged in the first 5 minutes after the big bang. The existing amounts of hydrogen and helium match theory perfectly – so well, in fact, that cosmologists claim this is the best evidence we have for the big bang. Things aren’t so good for the third element, lithium, however (New Scientist, 5 July 2008, p 28).
When we count up the lithium atoms held in stars, there is only one-third as much of the lithium-7 isotope as there should be. Another isotope, lithium-6, is overabundant: there may be as much as 1000 times too much of it.
So something in the big bang is not adding up. Is it a serious problem? Yes, says Gary Steigman of Ohio State University in Columbus, but it is not fatal. “There are too many successes for big-bang cosmology to be troubled by these lithium problems,” he says.
Others disagree. “The lithium problem is one of the very few hints that there may be a problem with the big bang,” says Jonathan Feng at the University of California, Irvine.
One thing that everyone does agree on is that things are getting worse. “The lithium-7 problem is more serious than ever,” says Joseph Silk at the University of Oxford. Improved observations of stars suggest they contain even less lithium-7 than previously thought. “The gap between prediction and observation has widened,” Steigman says.
So what is going on? The lithium-6 problem might just be an accounting issue: it is hard to discern lithium-6 abundances by looking at the light from stars. The lithium-7 shortfall might be due to destructive processes within stars, but there is no consensus as to what these processes might be. Others suggest the lithium-7 discrepancy is somehow linked to dark matter. “It will be extremely interesting to see what we learn about that when the Large Hadron Collider turns on,” Feng says.
13 more things: MAGIC results
CLAIMS that Einstein might not have all the answers are two-a-penny, but here’s one that stands apart. That’s because it springs from some of the finest minds in physics.
In 2005, researchers at the MAGIC gamma-ray telescope on La Palma in the Canary Islands were studying gamma-ray bursts emitted by the black hole in the centre of the Markarian 501 galaxy, half a billion light years away. The burst’s high-energy gamma rays arrived at the telescope 4 minutes later than the lower-energy rays. Both parts of the spectrum should have been emitted at the same time.
So is the time lag due to the high-energy radiation travelling slower through space? That wouldn’t make sense: it would contravene one of the central tenets of special relativity. According to Einstein, all electromagnetic radiation always travels through vacuum at the cosmic speed limit – the speed of light. The energy of the radiation should be absolutely irrelevant.
So what’s going on? The MAGIC result suggests that special relativity is only an approximation of how things really work. The observed lag might result from processes that occur at the most fundamental scale of space-time, the Planck length (10-35 metres). If so, that means we might finally have a way to test theories that aim to combine relativity and quantum theory into a quantum theory of gravity.
The mystery has only deepened with the launch last year of NASA’s Fermi gamma-ray space telescope. It has observed high-energy photons arriving up to 20 minutes behind zippier low-energy ones from a source 12 billion light years away. The hope is that Fermi will produce much more data that will enable researchers to rule out more mundane explanations and launch us into the era when we can finally put theories that attempt to unite quantum mechanics and gravity to the test.
13 more things: The elusive monopole
ELECTRICITY and magnetism are two sides of the same coin. There is supposed to be a deep symmetry between them. So why, when we see lone electrical charges such as electrons or protons, do we never see a lone magnetic pole – a monopole?
They are almost certainly out there: monopoles plays a pivotal role in the widely accepted “grand unified theories”, for example. GUTs suggest that the four forces of nature arose from one superforce that existed until moments after the big bang.
The trouble is, our universe is thought to contain no more than one of these “GUT monopoles” for every 1029 protons and neutrons in atomic nuclei: if there were any more than that, our most sensitive searches would have found one.
And it’s not like we can make them for ourselves. GUT monopoles are thought to be so massive that we don’t have powerful enough particle accelerators to create any. Not that this seems to bother physicists too much. Joe Polchinski, a theorist at the Kavli Institute for theoretical physics in Santa Barbara, California, has said that the existence of monopoles “seems like one of the safest bets that one can make about physics not yet seen”.
In the 1930s, Paul Dirac gave us an even better reason to believe in monopoles, when he showed that their existence would in turn explain the existence of electrons. “Dirac monopoles could be of any mass,” says Kimball Milton at the University of Oklahoma in Norman. So these monopoles could well turn up in our particle accelerators or in the decay products of cosmic ray collisions in the upper atmosphere.
Several searches have been carried out, but with no success. Does that mean we should give up? “We still might find relic monopoles in cosmic rays, so there is always hope,” says Milton.
He shares Polchinski’s confidence in monopoles. The fact that their existence is consistent with all known physics means they are almost certainly out there, he reckons. Milton believes in the principle espoused by the famous physicist Murray Gell-Mann: anything that is not forbidden is compulsory. “Magnetic monopoles are consistent with quantum mechanics; therefore they should exist,” says Milton.
13 more things: Noise from the edge of the universe
Are dud signals from a gravitational wave detector evidence that the universe is a holographic projection?
The GEO600 gravitational wave detector in Hanover, Germany, has not yet detected any gravitational waves. As a consolation prize, it may instead have uncovered the ultimate nature of reality.
In 2008, physicist Craig Hogan at the Fermi National Accelerator Laboratory in Batavia, Illinois, was trying to work out how we might test the idea that everything we see as physical reality is the result of a kind of projection from the boundary of the universe. This is known as the holographic principle.
The information held at the boundary is not smooth, but composed of “bits”, each one occupying an area that corresponds to the most fundamental quanta of distance in the universe. This is the Planck length, around 10-35 metres – far too small for us to see the individual bits. When this information is projected into the volume of the universe, however, each bit gets magnified. That means we might just be able to see pixellation in space-time.
The kinds of scales involved still mean it would only be detectable in the most sensitive instruments we have – such as the gravitational wave detectors looking for the ripples in space-time caused by violent cosmological events such as the collision of two black holes. Hogan worked out how the pixellation might manifest itself for GEO600 and sent his result to the researchers there.
By strange coincidence, the GEO600 team had been having problems with “noise” in their detectors. But here’s the kicker: the noise had uncannily similar characteristics as Hogan’s anticipated signal. Is it indeed the result of information that resides at the edge of the universe? “The issue is still unresolved,” says Karsten Danzmann, principal investigator for GEO600. “The noise is still there and we have no explanation.”
The answer may only come after the instrument is upgraded to make it even more sensitive, a step that is due to be completed this time next year.
13 more things: The nocebo effect
A diagnosis of terminal illness can come true, even if it’s wrong
When western anthropologists first heard reports of witch doctors who could issue deadly curses, they quickly found rational explanations. The families of the cursed often felt there was no point wasting food on the “walking dead”, for example. That’s why many of the cursed would die: simple starvation.
However, other case histories have come to light that defy attempts to explain them. In the 1970s, for example, doctors diagnosed a man with end-stage liver cancer, and told him he had just a few months to live. Though the patient died in the predicted time, an autopsy showed the doctors had been mistaken. There was a tiny tumour, but it had not spread. It seemed the doctors’ prognosis had been a death curse.
Though the mechanism remains a mystery, but at least now this kind of phenomenon has a name. The “nocebo effect” is the lesser-known opposite number of the placebo effect, and describes any case where putting someone in a negative frame of mind has an adverse effect on their health or well-being. Tell people a medical procedure will be extremely painful, for example, and they will experience more pain than if you had kept the bad news to yourself. Similarly, experiences of side effects within the placebo groups of drug trials have shown that a doctor’s warning about the possible side effects of a medicine makes it much more likely that the patient will report experiencing those effects.
This is not just in the mind: it is also about physical effects. The stress created by the nocebo effect can have a long-lasting impact on the heart, for example – perhaps serious enough to cause fatal damage.
The race is on to understand the precise mechanisms behind nocebo. Medical researchers are hoping that such an understanding will help to make the world a less stressful place. “It is a good way to understand anxiety, and to find methods to prevent it,” says Fabrizio Benedetti of the University of Turin, Italy.
Magazine issue 2724, published 5 September 2009