> 13 things that do not make sense
> 19 March 2005
> NewScientist.com news service
> Michael Brooks
> http://space.newscientist.com/article.ns?id=mg18524911.600
>
> 1 The placebo effectDON'T try this at home. Several times a day, for several days, you induce pain in someone. You control the pain
> with morphine until the final day of the experiment, when you replace the morphine with saline solution. Guess what? The saline
> takes the pain away.
> This is the placebo effect: somehow, sometimes, a whole lot of nothing can be very powerful. Except it's not quite nothing. When
> Fabrizio Benedetti of the University of Turin in Italy carried out the above experiment, he added a final twist by adding naloxone,
> a drug that blocks the effects of morphine, to the saline. The shocking result? The pain-relieving power of saline solution
> disappeared.
> So what is going on? Doctors have known about the placebo effect for decades, and the naloxone result seems to show that the placebo
> effect is somehow biochemical. But apart from that, we simply don't know.
> Benedetti has since shown that a saline placebo can also reduce tremors and muscle stiffness in people with Parkinson's disease
> (Nature Neuroscience, vol 7, p 587). He and his team measured the activity of neurons in the patients' brains as they administered
> the saline. They found that individual neurons in the subthalamic nucleus (a common target for surgical attempts to relieve
> Parkinson's symptoms) began to fire less often when the saline was given, and with fewer "bursts" of firing - another feature
> associated with Parkinson's. The neuron activity decreased at the same time as the symptoms improved: the saline was definitely
> doing something.
> We have a lot to learn about what is happening here, Benedetti says, but one thing is clear: the mind can affect the body's
> biochemistry. "The relationship between expectation and therapeutic outcome is a wonderful model to understand mind-body
> interaction," he says. Researchers now need to identify when and where placebo works. There may be diseases in which it has no
> effect. There may be a common mechanism in different illnesses. As yet, we just don't know.
>
> 2 The horizon problemOUR universe appears to be unfathomably uniform. Look across space from one edge of the visible universe to the
> other, and you'll see that the microwave background radiation filling the cosmos is at the same temperature everywhere. That may not
> seem surprising until you consider that the two edges are nearly 28 billion light years apart and our universe is only 14 billion
> years old.
> Nothing can travel faster than the speed of light, so there is no way heat radiation could have travelled between the two horizons
> to even out the hot and cold spots created in the big bang and leave the thermal equilibrium we see now.
> This "horizon problem" is a big headache for cosmologists, so big that they have come up with some pretty wild solutions.
> "Inflation", for example.
> You can solve the horizon problem by having the universe expand ultra-fast for a time, just after the big bang, blowing up by a
> factor of 1050 in 10-33 seconds. But is that just wishful thinking? "Inflation would be an explanation if it occurred," says
> University of Cambridge astronomer Martin Rees. The trouble is that no one knows what could have made that happen.
> So, in effect, inflation solves one mystery only to invoke another. A variation in the speed of light could also solve the horizon
> problem - but this too is impotent in the face of the question "why?" In scientific terms, the uniform temperature of the background
> radiation remains an anomaly.
> "A variation in the speed of light could solve the problem, but this too is impotent in the face of the question 'why?'"
>
> 3 Ultra-energetic cosmic raysFOR more than a decade, physicists in Japan have been seeing cosmic rays that should not exist. Cosmic
> rays are particles - mostly protons but sometimes heavy atomic nuclei - that travel through the universe at close to the speed of
> light. Some cosmic rays detected on Earth are produced in violent events such as supernovae, but we still don't know the origins of
> the highest-energy particles, which are the most energetic particles ever seen in nature. But that's not the real mystery.
> As cosmic-ray particles travel through space, they lose energy in collisions with the low-energy photons that pervade the universe,
> such as those of the cosmic microwave background radiation. Einstein's special theory of relativity dictates that any cosmic rays
> reaching Earth from a source outside our galaxy will have suffered so many energy-shedding collisions that their maximum possible
> energy is 5 × 1019 electronvolts. This is known as the Greisen-Zatsepin-Kuzmin limit.
> Over the past decade, however, the University of Tokyo's Akeno Giant Air Shower Array - 111 particle detectors spread out over 100
> square kilometres - has detected several cosmic rays above the GZK limit. In theory, they can only have come from within our galaxy,
> avoiding an energy-sapping journey across the cosmos. However, astronomers can find no source for these cosmic rays in our galaxy.
> So what is going on?
> One possibility is that there is something wrong with the Akeno results. Another is that Einstein was wrong. His special theory of
> relativity says that space is the same in all directions, but what if particles found it easier to move in certain directions? Then
> the cosmic rays could retain more of their energy, allowing them to beat the GZK limit.
> Physicists at the Pierre Auger experiment in Mendoza, Argentina, are now working on this problem. Using 1600 detectors spread over
> 3000 square kilometres, Auger should be able to determine the energies of incoming cosmic rays and shed more light on the Akeno
> results.
> Alan Watson, an astronomer at the University of Leeds, UK, and spokesman for the Pierre Auger project, is already convinced there is
> something worth following up here. "I have no doubts that events above 1020 electronvolts exist. There are sufficient examples to
> convince me," he says. The question now is, what are they? How many of these particles are coming in, and what direction are they
> coming from? Until we get that information, there's no telling how exotic the true explanation could be.
> "One possibility is that there is something wrong with the Akeno results. Another is that Einstein was wrong"
>
> 4 Belfast homeopathy resultsMADELEINE Ennis, a pharmacologist at Queen's University, Belfast, was the scourge of homeopathy. She
> railed against its claims that a chemical remedy could be diluted to the point where a sample was unlikely to contain a single
> molecule of anything but water, and yet still have a healing effect. Until, that is, she set out to prove once and for all that
> homeopathy was bunkum.
> In her most recent paper, Ennis describes how her team looked at the effects of ultra-dilute solutions of histamine on human white
> blood cells involved in inflammation. These "basophils" release histamine when the cells are under attack. Once released, the
> histamine stops them releasing any more. The study, replicated in four different labs, found that homeopathic solutions - so dilute
> that they probably didn't contain a single histamine molecule - worked just like histamine. Ennis might not be happy with the
> homeopaths' claims, but she admits that an effect cannot be ruled out.
> So how could it happen? Homeopaths prepare their remedies by dissolving things like charcoal, deadly nightshade or spider venom in
> ethanol, and then diluting this "mother tincture" in water again and again. No matter what the level of dilution, homeopaths claim,
> the original remedy leaves some kind of imprint on the water molecules. Thus, however dilute the solution becomes, it is still
> imbued with the properties of the remedy.
> You can understand why Ennis remains sceptical. And it remains true that no homeopathic remedy has ever been shown to work in a
> large randomised placebo-controlled clinical trial. But the Belfast study (Inflammation Research, vol 53, p 181) suggests that
> something is going on. "We are," Ennis says in her paper, "unable to explain our findings and are reporting them to encourage others
> to investigate this phenomenon." If the results turn out to be real, she says, the implications are profound: we may have to rewrite
> physics and chemistry.
>
>
> 5 Dark matterTAKE our best understanding of gravity, apply it to the way galaxies spin, and you'll quickly see the problem: the
> galaxies should be falling apart. Galactic matter orbits around a central point because its mutual gravitational attraction creates
> centripetal forces. But there is not enough mass in the galaxies to produce the observed spin.
> Vera Rubin, an astronomer working at the Carnegie Institution's department of terrestrial magnetism in Washington DC, spotted this
> anomaly in the late 1970s. The best response from physicists was to suggest there is more stuff out there than we can see. The
> trouble was, nobody could explain what this "dark matter" was.
> And they still can't. Although researchers have made many suggestions about what kind of particles might make up dark matter, there
> is no consensus. It's an embarrassing hole in our understanding. Astronomical observations suggest that dark matter must make up
> about 90 per cent of the mass in the universe, yet we are astonishingly ignorant what that 90 per cent is.
> Maybe we can't work out what dark matter is because it doesn't actually exist. That's certainly the way Rubin would like it to turn
> out. "If I could have my pick, I would like to learn that Newton's laws must be modified in order to correctly describe
> gravitational interactions at large distances," she says. "That's more appealing than a universe filled with a new kind of
> sub-nuclear particle."
> "If the results turn out to be real, the implications are profound. We may have to rewrite physics and chemistry"
>
> 6 Viking's methaneJULY 20, 1976. Gilbert Levin is on the edge of his seat. Millions of kilometres away on Mars, the Viking landers
> have scooped up some soil and mixed it with carbon-14-labelled nutrients. The mission's scientists have all agreed that if Levin's
> instruments on board the landers detect emissions of carbon-14-containing methane from the soil, then there must be life on Mars.
> Viking reports a positive result. Something is ingesting the nutrients, metabolising them, and then belching out gas laced with
> carbon-14.
> So why no party?Because another instrument, designed to identify organic molecules considered essential signs of life, found
> nothing. Almost all the mission scientists erred on the side of caution and declared Viking's discovery a false positive. But was
> it?
> The arguments continue to rage, but results from NASA's latest rovers show that the surface of Mars was almost certainly wet in the
> past and therefore hospitable to life. And there is plenty more evidence where that came from, Levin says. "Every mission to Mars
> has produced evidence supporting my conclusion. None has contradicted it."
> Levin stands by his claim, and he is no longer alone. Joe Miller, a cell biologist at the University of Southern California in Los
> Angeles, has re-analysed the data and he thinks that the emissions show evidence of a circadian cycle. That is highly suggestive of
> life.
> Levin is petitioning ESA and NASA to fly a modified version of his mission to look for "chiral" molecules. These come in left or
> right-handed versions: they are mirror images of each other. While biological processes tend to produce molecules that favour one
> chirality over the other, non-living processes create left and right-handed versions in equal numbers. If a future mission to Mars
> were to find that Martian "metabolism" also prefers one chiral form of a molecule to the other, that would be the best indication
> yet of life on Mars.
> "Something on Mars is ingesting nutrients, metabolising them and then belching out radioactive methane"
>
> 7 TetraneutronsFOUR years ago, a particle accelerator in France detected six particles that should not exist. They are called
> tetraneutrons: four neutrons that are bound together in a way that defies the laws of physics.
> Francisco Miguel Marquès and colleagues at the Ganil accelerator in Caen are now gearing up to do it again. If they succeed, these
> clusters may oblige us to rethink the forces that hold atomic nuclei together.
> The team fired beryllium nuclei at a small carbon target and analysed the debris that shot into surrounding particle detectors. They
> expected to see evidence for four separate neutrons hitting their detectors. Instead the Ganil team found just one flash of light in
> one detector. And the energy of this flash suggested that four neutrons were arriving together at the detector. Of course, their
> finding could have been an accident: four neutrons might just have arrived in the same place at the same time by coincidence. But
> that's ridiculously improbable.
> Not as improbable as tetraneutrons, some might say, because in the standard model of particle physics tetraneutrons simply can't
> exist. According to the Pauli exclusion principle, not even two protons or neutrons in the same system can have identical quantum
> properties. In fact, the strong nuclear force that would hold them together is tuned in such a way that it can't even hold two lone
> neutrons together, let alone four. Marquès and his team were so bemused by their result that they buried the data in a research
> paper that was ostensibly about the possibility of finding tetraneutrons in the future (Physical Review C, vol 65, p 44006).
> And there are still more compelling reasons to doubt the existence of tetraneutrons. If you tweak the laws of physics to allow four
> neutrons to bind together, all kinds of chaos ensues (Journal of Physics G, vol 29, L9). It would mean that the mix of elements
> formed after the big bang was inconsistent with what we now observe and, even worse, the elements formed would have quickly become
> far too heavy for the cosmos to cope. "Maybe the universe would have collapsed before it had any chance to expand," says Natalia
> Timofeyuk, a theorist at the University of Surrey in Guildford, UK.
> There are, however, a couple of holes in this reasoning. Established theory does allow the tetraneutron to exist - though only as a
> ridiculously short-lived particle. "This could be a reason for four neutrons hitting the Ganil detectors simultaneously," Timofeyuk
> says. And there is other evidence that supports the idea of matter composed of multiple neutrons: neutron stars. These bodies, which
> contain an enormous number of bound neutrons, suggest that as yet unexplained forces come into play when neutrons gather en masse.
>
>
> 8 The Pioneer anomalyTHIS is a tale of two spacecraft. Pioneer 10 was launched in 1972; Pioneer 11 a year later. By now both craft
> should be drifting off into deep space with no one watching. However, their trajectories have proved far too fascinating to ignore.
> That's because something has been pulling - or pushing - on them, causing them to speed up. The resulting acceleration is tiny, less
> than a nanometre per second per second. That's equivalent to just one ten-billionth of the gravity at Earth's surface, but it is
> enough to have shifted Pioneer 10 some 400,000 kilometres off track. NASA lost touch with Pioneer 11 in 1995, but up to that point
> it was experiencing exactly the same deviation as its sister probe. So what is causing it?
> Nobody knows. Some possible explanations have already been ruled out, including software errors, the solar wind or a fuel leak. If
> the cause is some gravitational effect, it is not one we know anything about. In fact, physicists are so completely at a loss that
> some have resorted to linking this mystery with other inexplicable phenomena.
> Bruce Bassett of the University of Portsmouth, UK, has suggested that the Pioneer conundrum might have something to do with
> variations in alpha, the fine structure constant (see "Not so constant constants", page 37). Others have talked about it as arising
> from dark matter - but since we don't know what dark matter is, that doesn't help much either. "This is all so maddeningly
> intriguing," says Michael Martin Nieto of the Los Alamos National Laboratory. "We only have proposals, none of which has been
> demonstrated."
> Nieto has called for a new analysis of the early trajectory data from the craft, which he says might yield fresh clues. But to get
> to the bottom of the problem what scientists really need is a mission designed specifically to test unusual gravitational effects in
> the outer reaches of the solar system. Such a probe would cost between $300 million and $500 million and could piggyback on a future
> mission to the outer reaches of the solar system (www.arxiv.org/gr-qc/0411077).
> "An explanation will be found eventually," Nieto says. "Of course I hope it is due to new physics - how stupendous that would be.
> But once a physicist starts working on the basis of hope he is heading for a fall." Disappointing as it may seem, Nieto thinks the
> explanation for the Pioneer anomaly will eventually be found in some mundane effect, such as an unnoticed source of heat on board
> the craft.
>
> 9 Dark energyIT IS one of the most famous, and most embarrassing, problems in physics. In 1998, astronomers discovered that the
> universe is expanding at ever faster speeds. It's an effect still searching for a cause - until then, everyone thought the
> universe's expansion was slowing down after the big bang. "Theorists are still floundering around, looking for a sensible
> explanation," says cosmologist Katherine Freese of the University of Michigan, Ann Arbor. "We're all hoping that upcoming
> observations of supernovae, of clusters of galaxies and so on will give us more clues."
> One suggestion is that some property of empty space is responsible - cosmologists call it dark energy. But all attempts to pin it
> down have fallen woefully short. It's also possible that Einstein's theory of general relativity may need to be tweaked when applied
> to the very largest scales of the universe. "The field is still wide open," Freese says.
>
> 10 The Kuiper cliffIF YOU travel out to the far edge of the solar system, into the frigid wastes beyond Pluto, you'll see something
> strange. Suddenly, after passing through the Kuiper belt, a region of space teeming with icy rocks, there's nothing.
> Astronomers call this boundary the Kuiper cliff, because the density of space rocks drops off so steeply. What caused it? The only
> answer seems to be a 10th planet. We're not talking about Quaoar or Sedna: this is a massive object, as big as Earth or Mars, that
> has swept the area clean of debris.
> The evidence for the existence of "Planet X" is compelling, says Alan Stern, an astronomer at the Southwest Research Institute in
> Boulder, Colorado. But although calculations show that such a body could account for the Kuiper cliff (Icarus, vol 160, p 32), no
> one has ever seen this fabled 10th planet.
> There's a good reason for that. The Kuiper belt is just too far away for us to get a decent view. We need to get out there and have
> a look before we can say anything about the region. And that won't be possible for another decade, at least. NASA's New Horizons
> probe, which will head out to Pluto and the Kuiper belt, is scheduled for launch in January 2006. It won't reach Pluto until 2015,
> so if you are looking for an explanation of the vast, empty gulf of the Kuiper cliff, watch this space.
>
> 11 The Wow signalIT WAS 37 seconds long and came from outer space. On 15 August 1977 it caused astronomer Jerry Ehman, then of Ohio
> State University in Columbus, to scrawl "Wow!" on the printout from Big Ear, Ohio State's radio telescope in Delaware. And 28 years
> later no one knows what created the signal. "I am still waiting for a definitive explanation that makes sense," Ehman says.
> Coming from the direction of Sagittarius, the pulse of radiation was confined to a narrow range of radio frequencies around 1420
> megahertz. This frequency is in a part of the radio spectrum in which all transmissions are prohibited by international agreement.
> Natural sources of radiation, such as the thermal emissions from planets, usually cover a much broader sweep of frequencies. So what
> caused it?
> The nearest star in that direction is 220 light years away. If that is where is came from, it would have had to be a pretty powerful
> astronomical event - or an advanced alien civilisation using an astonishingly large and powerful transmitter.
> The fact that hundreds of sweeps over the same patch of sky have found nothing like the Wow signal doesn't mean it's not aliens.
> When you consider the fact that the Big Ear telescope covers only one-millionth of the sky at any time, and an alien transmitter
> would also likely beam out over the same fraction of sky, the chances of spotting the signal again are remote, to say the least.
> Others think there must be a mundane explanation. Dan Wertheimer, chief scientist for the SETI@home project, says the Wow signal was
> almost certainly pollution: radio-frequency interference from Earth-based transmissions. "We've seen many signals like this, and
> these sorts of signals have always turned out to be interference," he says. The debate continues.
> "It was either a powerful astronomical event - or an advanced alien civilisation beaming out a signal"
>
> 12 Not-so-constant constantsIN 1997 astronomer John Webb and his team at the University of New South Wales in Sydney analysed the
> light reaching Earth from distant quasars. On its 12-billion-year journey, the light had passed through interstellar clouds of
> metals such as iron, nickel and chromium, and the researchers found these atoms had absorbed some of the photons of quasar light -
> but not the ones they were expecting.
> If the observations are correct, the only vaguely reasonable explanation is that a constant of physics called the fine structure
> constant, or alpha, had a different value at the time the light passed through the clouds.
> But that's heresy. Alpha is an extremely important constant that determines how light interacts with matter - and it shouldn't be
> able to change. Its value depends on, among other things, the charge on the electron, the speed of light and Planck's constant.
> Could one of these really have changed?
> No one in physics wanted to believe the measurements. Webb and his team have been trying for years to find an error in their
> results. But so far they have failed.
> Webb's are not the only results that suggest something is missing from our understanding of alpha. A recent analysis of the only
> known natural nuclear reactor, which was active nearly 2 billion years ago at what is now Oklo in Gabon, also suggests something
> about light's interaction with matter has changed.
> The ratio of certain radioactive isotopes produced within such a reactor depends on alpha, and so looking at the fission products
> left behind in the ground at Oklo provides a way to work out the value of the constant at the time of their formation. Using this
> method, Steve Lamoreaux and his colleagues at the Los Alamos National Laboratory in New Mexico suggest that alpha may have decreased
> by more than 4 per cent since Oklo started up (Physical Review D, vol 69, p 121701).
> There are gainsayers who still dispute any change in alpha. Patrick Petitjean, an astronomer at the Institute of Astrophysics in
> Paris, led a team that analysed quasar light picked up by the Very Large Telescope (VLT) in Chile and found no evidence that alpha
> has changed. But Webb, who is now looking at the VLT measurements, says that they require a more complex analysis than Petitjean's
> team has carried out. Webb's group is working on that now, and may be in a position to declare the anomaly resolved - or not - later
> this year.
> "It's difficult to say how long it's going to take," says team member Michael Murphy of the University of Cambridge. "The more we
> look at these new data, the more difficulties we see." But whatever the answer, the work will still be valuable. An analysis of the
> way light passes through distant molecular clouds will reveal more about how the elements were produced early in the universe's
> history.
>
> 13 Cold fusionAFTER 16 years, it's back. In fact, cold fusion never really went away. Over a 10-year period from 1989, US navy labs
> ran more than 200 experiments to investigate whether nuclear reactions generating more energy than they consume - supposedly only
> possible inside stars - can occur at room temperature. Numerous researchers have since pronounced themselves believers.
> With controllable cold fusion, many of the world's energy problems would melt away: no wonder the US Department of Energy is
> interested. In December, after a lengthy review of the evidence, it said it was open to receiving proposals for new cold fusion
> experiments.
> That's quite a turnaround. The DoE's first report on the subject, published 15 years ago, concluded that the original cold fusion
> results, produced by Martin Fleischmann and Stanley Pons of the University of Utah and unveiled at a press conference in 1989, were
> impossible to reproduce, and thus probably false.
> The basic claim of cold fusion is that dunking palladium electrodes into heavy water - in which oxygen is combined with the hydrogen
> isotope deuterium - can release a large amount of energy. Placing a voltage across the electrodes supposedly allows deuterium nuclei
> to move into palladium's molecular lattice, enabling them to overcome their natural repulsion and fuse together, releasing a blast
> of energy. The snag is that fusion at room temperature is deemed impossible by every accepted scientific theory.
> "Cold fusion would make the world's energy problems melt away. No wonder the Department of Energy is interested"