This is not the first time fundamental constants have been accused of changing over the lifetime of the universe. Most famously, there was controversy over the fine structure constant, alpha (α), which governs how light and electrons interact. Some physicists claimed it is changing while others said it was not (see "Speed of light may have changed recently").

The ratio of a proton's mass to that of an electron, known as mu, is among the most mysterious of constants. There is no explanation for why the proton's mass should be 1836 times that of the electron.

The constant governs the strong nuclear force, which holds protons and neutrons together in atomic nuclei, and is also responsible for binding the quarks - the building blocks which make up protons - neutrons and most other fundamental particles.
Distant quasars

Researchers at the Free University in Amsterdam in the Netherlands and the European Southern Observatory in Chile discovered the variation in mu. They did it by comparing the spectrum of molecular hydrogen gas in the laboratory to what it was in quasars 12 billion light years away. The spectrum depends on the relative masses of protons and electrons in the molecule.

"We concluded that the proton-electron mass ratio may have decreased by 0.002% in the past 12 billion years," says team member Wim Ubachs.

"This claimed result is very interesting if true," says Thibault Damour at the Institute of Advanced Scientific Studies (IHES) in Bures-sur-Yvette in France, who co-authored a 1996 paper that found no change in the fine structure constant, alpha.

Any change in mu, would support theories that posit extra dimensions. As these dimensions evolve, in a manner similar to our expanding 3D universe, the so-called constants would vary over both space and time. Or it may be that we still do not fully understand the proton: it may itself evolve through the universe's lifetime, leading to the observed variation.

"Extraordinary claims require extraordinary evidence and this evidence does not exist yet," says Victor Flambaum at the University of New South Wales, Australia. "This result must be confirmed by other groups before a revolution in cosmology is needed."

Journal reference: Physical Review Letters (vol 96, p 151101)

This advertisement was screened on US television in 2002. It encouraged viewers to log onto bipolarawareness.com, which takes you to a website called the Bipolar Help Center. Scroll down and you see the site belongs to pharmaceutical company Eli Lilly. Here you will find a "mood disorder questionnaire". In the TV ad, we see our heroine filling in this questionnaire, and the ad encourages viewers to follow her example: "Take the test you can take to your doctor, it can change your life... Getting a correct diagnosis is the first step in treating bipolar disorder. Help your doctor to help you."

This ad markets bipolar disorder. It can be seen as a genuine attempt to alert people who are unaware that they are suffering from one of the most debilitating and serious psychiatric diseases: manic-depressive illness, in which people undergo periods of extreme emotional lows and periods of extreme highs that can wreck lives.

The ad can also be seen as an example of disease mongering: selling a disease so you can sell treatments for it. It encourages people to view any variations from an even emotional keel as signs of an illness that requires treatment. While it does not mention any drugs, the website stresses the importance of long-term medication. At the time the ad was aired, Eli Lilly's drug olanzapine (Zyprexa) had just been approved by the US Food and Drug Administration for treating periods of mania, and the company was running trials aimed at establishing olanzapine as a "mood stabiliser".

Before 1995, the term "mood stabilisers" had barely been heard of. So what exactly are these drugs, and how effective and safe are they?

From the 1950s on, the depressions of manic-depressive illness were treated with antidepressants, and the manias with the drugs known as antipsychotics. Because doctors did not rush to take people off these drugs after episodes of illness, many patients remained on them for years. However, the only agent thought to prevent episodes of manic-depressive illness if taken on a permanent basis was lithium, a cheap trace element, though it was not originally referred to as a "mood stabiliser".

The drugs first described as "mood stabilisers" were anticonvulsants, a group used for treating epilepsy. Epileptic fits can cause changes in the brain that make future fits more likely - an effect called "kindling" - and it was once widely believed that anticonvulsants reduce or "quench" these changes. In the 1980s, Robert Post of the US National Institute of Mental Health suggested that anticonvulsants might stabilise moods by a comparable "quenching" effect - in other words, that long-term treatment with anticonvulsants might prevent an episode of mood disorder "kindling" future episodes.

Although anticonvulsants had occasionally been used for treating bipolar disorders, there was at the time little evidence of a preventive effect to support this analogy. Nevertheless, the idea that some drugs might stabilise moods appealed to doctors and their patients. It was also very attractive to pharmaceutical companies, which were starting to take an interest in the market for bipolar drugs.

Bipolar disorders entered the Diagnostic and Statistical Manual of Mental Disorders (DSM) in 1980. The criteria for bipolar I disorder (classic manic-depressive illness) included an episode of hospitalisation for mania. Since then, mood disorders that do not require hospitalisation have been described, such as bipolar II disorder, bipolar disorders NOS (not otherwise specified) and cyclothymia. With the emergence of these so-called "community" disorders, estimates for the prevalence of bipolar disorders have risen from 0.1 per cent of the population to 5 per cent or more. Along with this expansion in estimated prevalence - and in the market for drugs - have come new journals and a slew of bipolar societies and annual conferences, many heavily funded by drug companies.

In the industry's hands, the growth of awareness of "mood stabilisation" has been sensational. It started in 1995, the year the FDA granted Abbott Laboratories a licence to use the anticonvulsant sodium valproate (Depakote) to treat periods of mania. In the US, approval allows companies to advertise drugs for the licensed purpose, and in its ads for doctors Abbott described valproate as a "mood stabiliser" - a label that may have encouraged many to think it could do more than treat manias.

By 2001, this term featured in the titles or abstracts of more than 100 scientific papers a year (see Graph), and it has started to be applied to some antipsychotic drugs as well as to anticonvulsants like sodium valproate. Yet until 2000 no companies making antipsychotics had sought a licence for using these drugs as a "maintenance" treatment. What's more, academic review articles make it clear that there is still no consensus among psychiatrists on what a "mood stabiliser" is.

There has always been a rationale to using antipsychotics to treat the periods of mania that people with bipolar disorder go through. There is, however, no consensus on a theoretical rationale for the use of antipsychotics as a long-term treatment for bipolar disorder, and scant evidence of their effectiveness. Nevertheless, from 2000 onwards, Eli Lilly, Janssen and AstraZeneca, the makers of the antipsychotics olanzapine, risperidone (Risperdal) and quetiapine (Seroquel) respectively, marched in on this new territory and began the process of getting approval for using these drugs not just to treat mania but as long-term "mood stabilisers".

The result of these trends is that people with a bipolar disorder are now routinely prescribed a cocktail of expensive drugs on a permanent basis. Drug companies, often with the enthusiastic support of psychiatrists, have managed to firmly establish the idea that these disorders require lifelong preventive medication, not merely treatment for episodes of mania or depression.

For instance, Eli Lilly's Bipolar Help Center website states: "Staying on medication over the long haul is critical. Without it, symptoms will reappear and the illness will get worse." Similarly, information available from Janssen, the maker of Risperdal, states: "Medicines are crucially important in the treatment of bipolar disorders. Studies over the past twenty years have shown beyond the shadow of doubt that people who receive the appropriate drugs are better off in the long term than those who receive no medicine."

There is, however, much less evidence than many might think to support these claims. In the case of the community disorders now being pulled into the manic-depressive net, there is almost none at all, as drug trials have mostly involved people diagnosed with bipolar I disorder.

In fact, with the possible exception of lithium for bipolar I disorder, no randomised controlled trials show that patients with bipolar disorders who receive drugs do better in the long term than those who receive no medicine. Eli Lilly's olanzapine was approved by the FDA for the long-term treatment of bipolar I disorder in January 2004 on the basis of a randomised, placebo-controlled trial. But this trial essentially lasted only a year, and most apparent relapses occurred just after patients stopped taking olanzapine, which suggests that they were in fact suffering withdrawal symptoms. Even in the case of lithium, there is some dispute over what has been demonstrated.

It is true that this lack of evidence may stem in part from difficulties in conducting trials that last more than a few weeks for conditions as complex as manic-depressive illness. However, the existing evidence of benefit for one agent (lithium) and possible benefit for one more (olanzapine) must be weighed against the dangers. The potential toxicity of lithium is well known, and a consistent body of evidence shows that people undergoing regular, long-term treatment with antipsychotics have an increased risk of death. This and other known side effects of antipsychotics do not show up in the relatively short-term trials aimed at demonstrating treatment effects in psychiatry. There is also evidence from trials of antipsychotics for schizophrenia that there are significantly more suicides among those receiving the active drug than those on placebo.

There are also grounds for questioning whether the benefits supposedly demonstrated in clinical trials translate into therapeutic efficacy. In north Wales a century ago, patients with bipolar I disorder had on average four hospital admissions every 10 years. Today, despite dramatic improvements in services and treatment with the very latest drugs, bipolar I patients are admitted four times as often (History of Psychiatry, vol 16, p 423). This is not ordinarily what happens when treatments "work", but quite often is what happens when treatments have side effects.
Fearsome toll

Those selling bipolar disorder stress the disorder's fearsome toll in terms of suicides. Indeed, controversy over the role of antidepressants in triggering suicide has been recast by some as a result of mistaken diagnosis: if the doctor had only realised the patient was bipolar, the argument goes, they would not have mistakenly prescribed an antidepressant. Because of this suicide risk, most psychiatrists would find it difficult not to prescribe drugs for any person with bipolar disorder. Yet as real as this risk is, the best available evidence shows that medication does not help.

Jitschak Storosum of the Medicines Evaluation Board of the Netherlands and colleagues analysed all four placebo-controlled, double-blind, randomised trials of "mood stabilisers" for the prevention of manic-depressive episodes submitted to the board between 1997 and 2003 (The American Journal of Psychiatry, vol 162, p 799). They compared the suicide risk in patients on various drugs with those on placebo. Two suicides (equivalent to 493 per 100,000 person-years of drug exposure) and eight suicide attempts (1969 per 100,000 person-years of exposure) occurred in the 943 patients given an active drug. No suicides and two suicide attempts (1467 per 100,000 person-years of exposure) occurred in 418 patients on placebo. Based on these figures, I calculate that suicidal acts are 2.2 times as likely in those taking "mood stabilisers" compared with those on placebo.

If the efficacy of "mood stabilisers" is questionable while their dangers might include an increased risk of suicide, we should surely be very cautious about expanding their use. Yet in the US there is now a surge of diagnoses of bipolar disorder in children despite the facts that these children do not meet the usual criteria for bipolar I disorder and that until recently the general wisdom was that it was very rare for manic-depressive illness to start in the pre-teen years.

This trend is exemplified by the book The Bipolar Child by Demitri and Janice Papolos. Published in 2000, it sold 70,000 hardback copies in six months in the US. As the Star-Telegram newspaper in Fort Worth, Texas, reported in July 2000, The Bipolar Child made all the difference to a local girl, Heather Norris, then aged 2. Heather had been diagnosed with attention deficit hyperactivity disorder (ADHD), treatment of which seemed to be making her worse. After reading The Bipolar Child, her mother challenged her doctor to change the diagnosis - and the medication.

The book's authors have senior positions in a charity called the Juvenile Bipolar Research Foundation, whose sponsors include drug company Novartis. The charity's FAQ on what it calls "early onset" bipolar disorder states: "Adults seem to experience abnormally intense moods for weeks or months at a time, but children appear to experience such rapid shifts of mood that they commonly cycle many times within the day."

If we consider adults alone for a moment, there is already potential for creating an "epidemic" of bipolar disorder because people are being diagnosed based on criteria that depend upon subjective judgements rather than any objective criterion of disability, such as hospitalisation or being off work for a month. With children, the risk is even greater because diagnosis is based mainly on the reports of parents, with little scope in most clinical practice for critical scrutiny of the social forces influencing parenting. For instance, in an age in which both parents often have to work long hours and childcare centres reject "difficult" children, medication may be the easiest way to deal with behavioural problems.

Experts who appear willing to go so far as to accept the possibility that the first signs of bipolar disorder may be patterns of overactivity in utero can only compound these problems. If bipolar diagnoses in children were solely for research purposes, there might be little problem. However, drugs such as olanzapine and risperidone are now being given to preschoolers in the US.

Some research on the subject is adding fuel to the fire. What might once have been thought of as sober institutions, such as Massachusetts General Hospital in Boston, have run trials of olanzapine and risperidone on children with an average age of 4. The hospital recruited participants by running TV ads stating that difficult and aggressive behaviour in children aged 4 and up can stem from bipolar disorder. The ad does more than recruit children with a clear disorder: it suggests that everyday behavioural difficulties may be better seen in terms of a disorder. Given that bipolar disorder in children is all but unrecognised outside the US, it seems likely that a significant proportion of these children will not meet the conventional criteria for bipolar I disorder.

It is all but impossible for a short-term trial of sedative agents for treating any sort of state that involves periods of overactivity not to show some rating-scale changes that can be regarded as beneficial. This research thus appears predestined to validate the diagnosis and thus increase the pressure for treatment.

Several years after Heather Norris was diagnosed with bipolar disorder, the original rationale for mood stabilisation was greatly weakened by the results of the largest ever randomised trial of immediate versus deferred anticonvulsant therapy for people who had experienced a single seizure. The trial found that although immediate anti-epileptic drug treatment reduces the occurrence of seizures in the next one to two years, such treatment does not affect long-term remission in individuals with single or infrequent seizures. Yet the entire concept of "mood stabilisation" was based on an analogy with epilepsy, not on any demonstrations of long-term benefit of any particular drug.

The use of "mood stabilisers" as a long-term maintenance treatment for bipolar disorders is based more on wishful thinking than on a solid theoretical or empirical basis. There is good evidence that these drugs threaten the health and lives of adults taking them - who knows what lies in store for the growing number of young children given these complex agents? Only the health of drug companies' profit margins appears assured.

David Healy is a psychiatrist at the North Wales Department of Psychological Medicine, Cardiff University, UK. This is an edited version of an essay in PloS Medicine, one of a series of articles on disease mongering available here.
From issue 2547 of New Scientist magazine, 15 April 2006, page 38

Dr. Hugh Berryman, research professor, was one of only 11 experts from across the United States to scrutinize the bones of Kennewick Man, a 9,300-year-old skeleton found 10 years ago along the Columbia River at Kennewick, Wash.

"It's one of the oldest skeletons, one of the earliest individuals that populated this continent," Berryman says. "And we have a chance to look at those remains and learn from them what they tell us about the past and who these people were."

The 380 bones are being preserved at the University of Washington's Burke Museum under an agreement with the U.S. Army Corps of Engineers, which controls the land on which Kennewick was discovered. Berryman says he was between two and three feet deep in the ground. The burial miraculously saved the bones from the elements, the animals, machinery and man for centuries, and ancient deposits of calcium carbonate on the bones allowed the researchers to determine the positioning of the bones in the ground.

"We have evidence that the bones were still in anatomic order," Berryman says. "He was still articulated, and he appears to have been a burial. So once something is buried, that moves it at a depth that perhaps the coyotes, the wolves, scavengers could not get to it."

The July 2005 research was very nearly derailed when the Corps initially decided to turn Kennewick over to a coalition of Native American tribes. Eight scientists filed a federal lawsuit to gain permission to study the skeleton. A federal judge, whose ruling later was upheld by the Ninth U.S. Circuit Court of Appeals, decided in favor of the scientists after determining that the tribes could not prove a direct cultural affiliation with Kennewick.

Berryman says the information that can be gleaned from Kennewick came close to being lost forever.

"Since 1990, we've lost most of the skeletal remains from groups," Berryman says. "It's a shame that a lot of these groups are already gone. We have no way of knowing what kind of movements there were in prehistoric times, where these people came from, who they were related to, what other tribal groups they might be related to."

What the experts were able to ascertain from their brief encounter with Kennewick is that he did not look like a Native American. In fact, Berryman says Kennewick's facial features are most similar to those of a Japanese group called the Ainu, who have a different physical makeup and cultural background from the ethnic Japanese.

Some Ainu's facial features appear European. Their eyes may lack the Asian almond-shaped appearance, and their hair may be light and curly in color. However, this does not mean that Kennewick Man necessarily was European in origin. His features more closely resemble those of the natives of the Pacific Rim than those of Native Americans.

Berryman, a fracture expert who was trained in the fine art of picking apart dead people at the University of Tennessee's "Body Farm," also documented three types of bone breaks in Kennewick-fractures that were suffered in his lifetime and then healed, fractures that happened after his burial, and fractures that occurred when the skeleton was eroded from the riverbank.

Part of a spear had remained lodged in Kennewick's right hip bone at a 77-degree angle, but, remarkably, the spear did not cause his death. The cause of his demise remains a mystery. What is known is that this athletic, rugged hunter suffered many physical traumas before finally expiring in his mid-to-late 30s.

"The muscle markings are pretty pronounced," Berryman says."He was probably a well-built individual. The bones of the right arm were larger than the left."

The bigger right arm can be explained by the 18-to-24-inch-long atlatl, or spear thrower, that gave him and his contemporaries the ability to propel a spear up to the length of a football field in order to kill their food. Kennewick died long before the invention of the bow and arrow.

Berryman says Kennewick has only begun to reveal the story of his life and times, and it would be tremendous to have other scientists examine his bones.

"It was a lot slower process than we thought," Berryman says. "The first day, all day, we looked at one bone, one femur. And then we realized at the end of the day that we were going to be lucky to be able to cover this the way that it should be in a week-and-a-half."

Age, ancestry, sex, height, pathologies, types of trauma, even whether a woman has given birth-all can be determined just from examining a skeleton, says Berryman, who often is called upon to give expert testimony on bones in criminal trials.

"Bone is great at recording its own history," he says."Throughout your life, there are different things that you do, and they may leave little signs in the bone. If you can read those signs, it's almost like interviewing a person."'

But studying the precise risk has been hard because most long GRBs occur in very distant, barely visible galaxies. Only four have been spotted within 2 billion light years of Earth. Kris Stanek of Ohio State University in Columbus presented data on the latest of these, GRB 060218, which occurred on 18 February in the constellation Aries, to his colleagues. "I was surprised that people were more interested in the host galaxies than the burst itself," he says.

This sparked a discussion that led the team to compare the host galaxies of the four GRBs with 70,000 nearby galaxies studied by the Sloan Digital Sky Survey. They found that the galaxies housing the bursts had levels of heavy elements that were only 10 per cent of the average, and 20 per cent that of the Milky Way (www.arxiv.org/astro-ph/0604113). "This is very unlikely to be a coincidence," says Stanek.

Theorist Stan Woosely of the University of California at Santa Cruz has an explanation. Long GRBs are thought to be caused by the collapse of gigantic fast-rotating "Wolf-Rayet" stars that have lost their outer layer of hydrogen. In metal-rich galaxies, heavy elements on the star's surface should absorb the momentum of the light coming from inside the star, pushing off the outer layers. This would reduce the star's spin, making the eventual collapse less violent and a GRB less likely.

Adrian Melott of the University of Kansas in Lawrence and Brian Thomas of Washburn University in Topeka, Kansas - who warned of the dangers of GRBs - are not convinced that our galaxy is safe. Thomas points out that the Milky Way could merge with or swallow smaller, metal-poor galaxies suitable for GRBs.

Also, a study by Armen Atoyan of the University of Montreal in Canada and his colleagues, due to be published in The Astrophysical Journal, claims that a source of gamma rays in our galaxy, about 40,000 light years away, is a remnant of a GRB that went off about 10,000 to 20,000 years ago. Luckily it wasn't pointed at us, says Atoyan. "If he is right, it provides a counter argument," says Melott.

Stanek, however, argues that the source seen by Atoyan is more likely the leftovers of an unusually energetic supernova.
From issue 2548 of New Scientist magazine, 19 April 2006, page 12

Last month, analysts at two Washington-based think tanks, the Center for Defense Information (CDI) and the Henry L. Stimson Center, reported that the Pentagon's convoluted $439 billion budget plans for 2007 include almost a billion dollars for developing and testing space weapons systems. While these have not been explicitly listed as such, they are "hidden in plain sight" within Missile Defense Agency and air force projects, says CDI's director Theresa Hitchens.

At least three types of space weapon are in the Pentagon pipeline. The Multiple Kill Vehicles project will look at using spacecraft to launch missiles that would carry a clutch of impacting projectiles designed to damage other spacecraft. The Missile Defense Agency's MicroSat project will investigate whether a satellite could sense the position of an enemy satellite and ram it. Finally, part of air force's laser weapons programme will be aimed at using ground-based lasers to knock out a spacecraft.

The CDI fears that the Pentagon might surreptitiously build up a weapons infrastructure by sending systems like these into space, ostensibly as prototypes for testing, and simply leaving them there. This would allow space weapons to become a fait accompli without congressional or public debate. "Space weapons are extremely destabilising politically so the DoD is getting around any debate by developing systems it says are just designed to test their capabilities," says CDI analyst Victoria Samson. "The Pentagon simply finds it easier to ask for forgiveness later rather than for permission now."

It is not just the political aspect of weaponising space that is causing concern. Near-Earth space could suffer serious pollution if anti-satellite (ASAT) weapons are used. An international relations conference in San Diego, California, heard on 25 March that destroying satellites would create large amounts of orbiting debris that could have a devastating effect on other spacecraft. "The potential for debris due to space weapons use was a big issue," says David Webb of Leeds Metropolitan University in the UK. "Even some in the American military were against using anti-satellite weapons owing to the debris issue."

The risk of damage to spacecraft by conventional debris is considerable. On 29 March a piece of space junk slammed into a Russian broadcasting satellite, puncturing it and venting a jet of liquid coolant that sent it spinning. The crippled craft had to be pushed into high orbit and deactivated. Incidents like this could become increasingly common if satellites become targets for attack, rendering near-Earth space almost a no-go area for spacecraft, Webb says.

Despite such risks, the economic and strategic importance of communications, surveillance and navigation satellites is now so great that the US considers it imperative to develop weapons to defend them. Much everyday technology, such as multi-channel TV and in-car satellite navigation, relies on satellite links, so attacks on commercial spacecraft could have severe economic consequences. The military importance of satellites was seen during the invasion of Iraq in 2003, for instance, when high-resolution imaging satellites showed where Iraqi troops were, while GPS was used to guide munitions and robotic aircraft towards them. As a result, the US military now believes it needs space weapons to deter other countries from attacking its satellites.

According to the Deparment of Defense, the US is not the only country developing space weapons. In its report to Congress on China's military power last year, it states: "China is working on, and plans to field, ASAT systems." These are thought to include ground-based lasers, including low-power systems to blind or dazzle spy satellites and higher-power lasers to destroy spacecraft. In 2004, the DoD reported that China had developed a micro-satellite ASAT weapon that attaches itself to larger spacecraft and destroys them. Webb, however, says the information came from an "unreliable" military enthusiast's website in Hong Kong.

Meanwhile, the Israeli parliament's Foreign Affairs and Defense Committee last year urged its government to develop ASAT technology. The country is already an enthusiastic partner in the US National Missile Defense (NMD) system, which uses surface-based radar to detect incoming missile-launched warheads, with a view to launching more missiles to intercept them out in space.
Death rays for real

The development of anti-satellite weapons is being stimulated by advances in powerful laser and microwave beams, which would form the basis of so-called "directed energy" weapons. "Advances in power density from chemical and free-electron lasers have been possible in the lab for a decade," says Doug Beason, a directed energy specialist at the Los Alamos National Laboratory in New Mexico and a science adviser to presidents George Bush senior and Bill Clinton. "Being able to do it in a portable way, so it can be used on the battlefield, is now becoming possible."

It was a lack of portable lasers that pulled the rug from under the Strategic Defense Initiative ("Star Wars") proposed in the 1980s by President Ronald Reagan. Now improvements in technologies such as supercapacitors, which can discharge large quantities of energy into a free-electron laser, have made them possible.

A key advance is the chemical oxygen iodine laser (COIL) that will form the heart of the Missile Defence Agency's huge Airborne Laser - a Boeing 747 designed to shoot down nuclear missiles as they launch hundreds of kilometres away. The chemical components that produce the excited oxygen atoms which donate energy to iodine molecules, causing them to generate laser light, have been shrunk enough to make the idea workable. Yet despite the $7 billion spent on it so far, the Airborne Laser has yet to be fired.

The UN's 1967 Outer Space Treaty forbids the stationing of weapons of mass destruction in space. There is no treaty preventing other weapons being stationed there, however, and a proposed treaty to prevent an arms race in outer space (PAROS) has been consistently blocked by the US and Israel. PAROS has been on the agenda of the UN Conference on Disarmament in Geneva, Switzerland, since 1998, but no framework for considering the issue has yet been agreed, despite attempts by Russia and China to promote debate.

Even without a ban on space weapons, it is not clear why the Pentagon's ASAT research is needed. Technologies already in development could do the job just as well, many analysts say. For example, steerable mirrors in space could be used together with a ground-based or airborne laser to knock out spacecraft, Beason says in E-Bomb, his recent book on directed energy weapons. And Michael O'Hanlon, a strategic arms analyst at the Brookings Institution in Washington DC, says the interceptor missiles used by the NMD could be adapted to attack satellites.

According to O'Hanlon, the political cost of testing new ASAT weapons in peacetime ought to rule them out. "To develop new ASATs now would reinforce the image of an America out of control," he says.
From issue 2547 of New Scientist magazine, 13 April 2006, page 30

After that, the planet's environment grew increasingly hostile. By 3.5 billion years ago, Mars had devolved into the frigid, arid orb humans are exploring today - "not a pleasant place for any form of life, even a microbe," notes John Mustard, a Brown University scientist and a member of the team conducting the analysis.

That said, the team also concludes that if life ever gained a foothold, the best places to look for evidence would be in three clay-rich regions on the planet's surface.

The analysis, which appears in Friday's issue of the journal Science, comes from an international team of planetary scientists. The team is led by Jean-Pierre Bibring, with the Institut d'Astrophysique Spatiale in Orlay, France, and drew heavily on data gathered by the European Space Agency's Mars Express Orbiter. The orbiter arrived Christmas Day in 2003.

Its initial mission length has been extended, and the orbiter has mapped the distribution of minerals over some 90 percent of the planet's surface.

The study also draws on information from US orbiters and the two Mars Exploration Rovers currently hunting for winter hibernation spots on Mars. Geologically speaking, the planet's watery period was brief, the team found.

For Mars' first 600 million years, it had plenty of water, hospitable temperatures, and low acid levels. The team gleaned this from glimpses of the planet's oldest rocks, laid bare through erosion, cratering, and large temblors.

Of particular interest are the clays they found. Yet some uncertainty remains about how the clays formed.

The team leaves open the possibility that the Martian surface may never have had large amounts of water. The exposed clays may have formed beneath the surface - which would imply that the planet has always been cold and dry.

For the next 500 million years, the team found, the planet's mighty volcanoes erupted in a series of events that filled the atmosphere with sulfur. This sulfur fell back to the surface as sulfuric acid. At the same time, it began to lose its atmosphere - either blasted free by collisions with large leftovers from planet formation, or perhaps when the planet's internal dynamo finally gave out and its magnetic field vanished.

Over the next 300 million years, the planet arrived at the frigid, rust-red configuration that holds today. Dr. Mustard notes that the clay deposits in particular should be tempting targets for the US Mars Reconnaissance Orbiter, which currently is working its way into its final science-gathering orbit around the planet.

Ultimately, these may be the best locations to send landers hunting for signs that Mars might have once harbored simple life-forms.

Air diverted by plasma heating successfully exerted force on the model and demonstrated that the plasma actuator concept is a viable area for further study and development.

AFRL's Mach 5 plasma channel wind tunnel relies upon a vacuum system to generate low-density air flows. A high electrical voltage placed between metal electrodes on a model in the plasma channel ionizes the air between them and creates plasma, a state of matter where electrons are stripped from molecules. While usually occurring at extreme temperatures and pressures such as the conditions experienced within a star or by a hypersonic vehicle during flight, man-made plasma is found in items like fluorescent light bulbs and computer screen plasma displays.

The Boundary Layers and Hypersonics program is developing knowledge of fluid physics to facilitate future aerospace vehicle designs. The program focuses on characterizing, predicting and controlling high-speed fluid dynamic phenomena including boundary layer transition, shock/boundary layer, shock/shock interactions and other airframe propulsion integration phenomena including real-gas effects, plasma aerodynamics, magnetohydrodynamics and high-speed flow heat transfer.

Described in the April 14th issue of the journal Science, the nanogenerators produce current by bending and then releasing zinc oxide nanowires - which are both piezoelectric and semiconducting. The research was sponsored by the National Science Foundation (NSF), the NASA Vehicle Systems Program and the Defense Advanced Research Projects Agency (DARPA).

"There is a lot of mechanical energy available in our environment," said Zhong Lin Wang, a Regents Professor in the School of Materials Science and Engineering at the Georgia Institute of Technology. "Our nanogenerators can convert this mechanical energy to electrical energy. This could potentially open up a lot of possibilities for the future of nanotechnology."

Nanotechnology researchers have proposed and developed a broad range of nanoscale devices, but their use has been limited by the sources of energy available to power them. Conventional batteries make the nanoscale systems too large, and the toxic contents of batteries limit their use in the body. Other potential power sources also suffer from significant drawbacks.

"We can build nanodevices that are very small, but if the complete integrated system must include a large power source, that defeats the purpose," added Wang, who also holds affiliated faculty positions at Peking University and the National Center for Nanoscience and Technology of China.

The nanogenerators developed by Wang and graduate student Jinhui Song use the very small piezoelectric discharges created when zinc oxide nanowires are bent and then released. By building interconnected arrays containing millions of such wires, Wang believes he can produce enough current to power nanoscale devices.

To study the effect, the researchers grew arrays of zinc oxide nanowires, then used an atomic-force microscope tip to deflect individual wires. As a wire was contacted and deflected by the tip, stretching on one side of the structure and compression on the other side created a charge separation - positive on the stretched side and negative on the compressed side - due to the piezoelectric effect.

The charges were preserved in the nanowire because a Schottky barrier was formed between the AFM tip and the nanowire. The coupling between semiconducting and piezoelectric properties resulted in the charging and discharging process when the tip scanned across the nanowire, Wang explained.

When the tip lost contact with the wire, the strain was released - and the researchers measured an electrical current. After the strain release, the nanowire vibrated through many cycles, but the electrical discharge was measured only at the instant when the strain was released.

To rule out other potential sources of the current, the researchers conducted similar tests using structures that were not piezoelectric or semiconducting. "After a variety of tests, we are confident that what we are seeing is a piezoelectric-induced discharge process," Wang said.

The researchers grew the nanowire arrays using a standard vapor-liquid-solid process in a small tube furnace. First, gold nanoparticles were deposited onto a sapphire substrate placed in one end of the furnace. An argon carrier gas was then flowed into the furnace as zinc oxide powder was heated. The nanowires grew beneath the gold nanoparticles, which serve as catalysts.

The resulting arrays contained vertically-aligned nanowires that ranged from 200 to 500 nanometers in length and 20 to 40 nanometers in diameter. The wires grew approximately 100 nanometers apart, as determined by the placement of the gold nanoparticles.

A film of zinc oxide also grew between the wires on the substrate surface, creating an electrical connection between the wires. To that conductive substrate, the researchers attached an electrode for measuring current flow.

Though attractive for use inside the body because zinc oxide is non-toxic, the nanogenerators could also be used wherever mechanical energy - hydraulic motion of seawater, wind or the motion of a foot inside a shoe - is available. The nanowires can be grown not only on crystal substrates, but also on polymer-based films. Use of flexible polymer substrates could one day allow portable devices to be powered by the movement of their users.

"You could envision having these nanogenerators in your shoes to produce electricity as you walk," Wang said. "This could be beneficial to soldiers in the field, who now depend on batteries to power their electrical equipment. As long as the soldiers were moving, they could generate electricity."

Current could also be produced by placing the nanowire arrays into fields of acoustic or ultrasonic energy. Though they are ceramic materials, the nanowires can bend as much as 50 degrees without breaking.

The next step in the research will be to maximize the power produced by an array of the new nanogenerators. Wang estimates that they can convert as much as 30 percent of the input mechanical energy into electrical energy for a single cycle of vibration. That could allow a nanowire array just 10 microns square to power a single nanoscale device - if all the power generated by the nanowire array can be successfully collected.

"Our bodies are good at converting chemical energy from glucose into the mechanical energy of our muscles," Wang noted. "These nanogenerators can take that mechanical energy and convert it to electrical energy for powering devices inside the body. This could open up tremendous possibilities for self-powered implantable medical devices."

Researchers at the Florida Institute for Human and Machine Cognition envision their work giving Army Rangers 360-degree unobstructed vision at night and allowing Navy SEALs to sense sonar in their heads while maintaining normal vision underwater - turning sci-fi into reality.

The device, known as "Brain Port," was pioneered more than 30 years ago by Dr. Paul Bach-y-Rita, a University of Wisconsin neuroscientist. Bach-y-Rita began routing images from a camera through electrodes taped to people's backs and later discovered the tongue was a superior transmitter.

A narrow strip of red plastic connects the Brain Port to the tongue where 144 microelectrodes transmit information through nerve fibers to the brain. Instead of holding and looking at compasses and bulky-hand-held sonar devices, the divers can processes the information through their tongues, said Dr. Anil Raj, the project's lead scientist.

In testing, blind people found doorways, noticed people walking in front of them and caught balls. A version of the device, expected to be commercially marketed soon, has restored balance to those whose vestibular systems in the inner ear were destroyed by antibiotics.

Michael Zinszer, a veteran Navy diver and director of Florida State University's Underwater Crime Scene Investigation School, took part in testing using the tongue to transmit an electronic compass and an electronic depth sensor while in a swimming pool.

He likened the feeling on his tongue to Pop Rocks candies.

"You are feeling the outline of this image," he said. "I was in the pool, they were directing me to a very small object and I was able to locate everything very easily."

Underwater crime scene investigators might use the device to identify search patterns, signal each other and "see through our tongues, as odd as that sounds," Zinszer said.

Raj said the objective for the military is to keep Navy divers' hands and eyes free. "It will free up their eyes to do what those guys really want to, which is to look for those mines and see shapes that are coming out of the murk."

Sonar is the next step. A lot depends on technological developments to make sonar smaller - hand-held sonar is now about the size of a lunch box.

"If they could get it small enough, it could be mounted on a helmet, then they could pan around on their heads and they could feel the sonar on their tongues with good registration to what they are seeing visually," Raj said.

The research at the Florida institute, the first to research military uses of sensory augmentation, is funded by the Defense Department. The exact amount of the expenditure is unavailable.

Raj and his research assistants spend hours at the University of West Florida's athletic complex testing the equipment at an indoor pool. Raj does the diving himself.

They plan to officially demonstrate the system to Navy and Marine Corps divers in May. If the military screeners like what they see, it could be put on a "rapid response" to quickly get in the hands of military users within the next three to six months.

Work on the infrared-tongue vision for Army Rangers isn't as far along. But Raj said the potential usefulness of the night vision technology is tremendous. It would allow soldiers to work in the dark without cumbersome night-vision goggles and to "see out the back of their heads," he said.