For the planet it’s geoengineer or bust We’re clearly failing to reduce emissions so it may be time to adjust the Earth’s thermostat
high-rise cities closer to the poles – would be a last resort. Aside from anything else, it is far from being the most practical option: any attempt at mass migration is likely to fuel wars, political power struggles and infighting. So what are the alternatives? The most obvious answer is to radically reduce carbon dioxide levels now, by fast-tracking green technologies and urgently implementing energy-efficient measures. But the changes aren’t coming nearly quickly enough and global emissions are still rising. As a result, many scientists are now turning to “Earth’s plan B” (see page 8). Plan B involves making sure we have large-
DESPITE the numerous warnings about extreme weather, rising sea levels and mass extinctions, one message seems to have got lost in the debate about the impact of climate “Perhaps geoengineering projects change. A warmer world won’t just be can avert the more horrifying inconvenient. Huge swathes of it, including consequences of climate change” most of Europe, the US and Australia as well as all of Africa and China will actually be uninhabitable – too hot, dry or stormy to scale geoengineering technologies ready sustain a human population. and waiting to either suck CO2 out of the atmosphere or deflect the sun’s heat. Most This is no mirage. It could materialise if the climate scientists were once firmly against world warms by an average of just 4 °C, which fiddling with the Earth’s thermostat, fearing some models predict could happen as soon that it may make a bad situation even worse, as 2050. This is the world our children and or provide politicians with an excuse to sit on grandchildren are going to have to live in. their hands and do nothing. So what are we going to do about it? Now they reluctantly acknowledge the sad One option is to start planning to move truth that we haven’t managed to reorder the the at-risk human population to parts of world fast enough to reduce CO2 emissions the world where it will still be cool and wet and that perhaps, given enough funding, (see page 28). It might seem like a drastic research and political muscle, we can indeed move, but this thought experiment is not design, test and regulate geoengineering about scaremongering. Every scenario is projects in time to avert the more horrifying extrapolated from predictions of the latest consequences of climate change. climate models, and some say that 4 °C may Whatever we do, now is the time to act. The actually turn out to be a conservative estimate. alternative is to plan for a hothouse world that Clearly this glacier-free, desertified world – none of us would recognise as home. ■ with its human population packed into
Forensic science: guilty as charged SINCE it began in 1992, the Innocence Project has deployed DNA evidence to exonerate 232 people previously convicted in American courts. Faulty interpretation of forensic evidence had contributed to around half the wrongful convictions. This failure of forensic science to protect the innocent is underlined in a report from the US National Academy of Sciences (see page 6). A core concern was the unreliability of traditional techniques compared with DNA methods. These older techniques, which are still relevant, need stronger scientific backing – yet it is DNA that gets most of the research funding. Let’s hope the report will change that. For justice to prevail, we need to put forensic science onto the firmest possible footing and subject it to the rigorous testing it deserves. ■
Volte-Facebook IN THE wake of a recent brouhaha, Facebook has backtracked on changes that potentially gave the social networking site indefinite rights to its users’ data – even from closed accounts (see page 12). But a closer look at its terms and conditions suggests Facebook has lost nothing but face. Users, perhaps unknowingly, have always granted Facebook a licence to peddle their information to anyone willing to pay. The controversy is a timely reminder that social networks want more than your company, and that it pays to read the small print. ■
What’s hot on NewScientist.com SPACE Second man on moon critical of NASA The space agency’s performance since the Apollo programme has been “lacklustre” and NASA needs “serious reform or significant organisational overhaul”, says Apollo legend Buzz Aldrin
if they’ve been somewhere before, just like us FORENSICS Inside the skull of a suicide By combining surface scans of the body with CT and MRI scans, it is possible to work out what happened to a person without cutting them open
TECH Mirrors: the next generation Explore images of mirrors that can reflect text without reversing it, capture a 360-degree view without distortion or help robots climb stairs, all thanks to computer-aided design
PSYCHOLOGY Scared of heights? Find out why People who shudder atop skyscrapers or whose knees buckle crossing bridges have trouble perceiving the vertical dimension
ROBOTICS ‘Déjà vu robots’ don’t get lost Robots that make maps as they go need to detect
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28 February 2009 | NewScientist | 3
Cut-and-dried fire hazard WE HAVE turned the world’s third-largest rainforest region into a tinderbox that the warming world will help ignite. So concludes a new study of forest fires in Sumatra and Borneo in Indonesia. Robert Field, an atmospheric physicist at the University of Toronto in Canada, and his colleagues examined the fire history of forests in Indonesia by analysing five decades of visibility records at nearby airports. Droughts – usually during El Niño seasons in the Pacific – have triggered huge fires in Indonesia seven times since 1960. But Field’s team found that until 1980 the fires were limited to Sumatra, where human activity and deforestation were greatest. Borneo’s forests did not burn. However, after humans began
large-scale encroachment on Borneo in the 1980s – with deforestation rising above 2 per cent per year – its forests too suffered massive fires during periods of drought. Field says clearing vegetation for farming reduces the moisture in the ecosystems, leaving them vulnerable to wildfires (Nature Geoscience, DOI: 10.1038/ngeo443). The biggest source of greenhouse gases released by forest fires in southeast Asia is not the trees, says Field. Instead, it is the burning of peat in the deep swamps on which many forests grow. So Field’s findings add to concern over Indonesia now ending a two-year moratorium on allowing oil palm and tree crops to be planted on peatlands. Such a move will lead to more fires, Field warns.
Flu’s Achilles’ heel THE flu virus is a slippery customer, expert at escaping attack by our immune system. But there is a chink in its defences that could lead to a universal flu vaccine. We can get flu repeatedly because the virus evolves: its surface proteins change, so the antibodies generated by one bout are not effective a second time. For the same reason, the vaccine for one year’s strain won’t work in later years. Now Wayne Marasco at Harvard University and his team may have found a way round this. The flu virus’s main surface protein, haemagglutinin, is lollipop-shaped, and existing vaccines stimulate the production of antibodies that bind to its big
“When injected into people, the antibodies lasted long enough to offer protection in a pandemic” round head – which changes every year. But in a library of human antibodies, Marasco’s team found a few that target proteins on the “stalk”. These proteins barely 4 | NewScientist | 28 February 2009
change between flu strains, which suggests they don’t evolve quickly (Nature Structural and Molecular Biology, DOI: 10.1038/nsmb.1566). Marasco’s team suspected that the prominent head of the lollipop normally attracts the attention of the immune system away from the stalk. If the immune system could be persuaded to target these unchanging proteins, they reasoned, it might be possible to provide protection year after year. His team produced antibodies to these stalk proteins in bulk, and injected them into mice before and after they were infected with a range of flu viruses, including H5N1 bird flu, pandemic H1N1, and ordinary flu. The antibodies protected or cured the animals in each case. In cell cultures, the viruses did not evolve to escape the stalk antibodies, so a vaccine based on them should, in theory, work for longer than a year. In a pandemic, the antibodies alone might offer useful protection. They last more than three weeks when injected into people, which could keep them alive long enough to make their own antibodies.
The clap is back GONORRHOEA is becoming dangerously antibiotic-resistant. The sexually transmitted disease, which can lead to infertility in men and women, is treatable with antibiotics. But following recent resistance to the quinolone family of antibiotics in the US, UK and Australia, authorities in these countries now recommend cephalosporins, the only option besides quinolones. In the latest setback, quinolone resistance seems to have spread to
Canada. Kaede Ota and her colleagues at the Hospital for Sick Children in Toronto found that quinolone-resistant infections in Ontario soared from 4 per cent of infections in 2002 to 28 per cent in 2006 (Canadian Medical Association Journal, DOI: 10.1503/ cmaj.080222). The team blames the surge on a mixture of unsafe sex and people not completing prescribed courses of antibiotics. The fear is that strains resistant to all antibiotics will appear. The first cephalosporin-resistant strains appeared in 2008 in Japan.
Comet Lulin drops by for a visit THE Earth had company this week, when comet Lulin passed within 61 million kilometres of us, almost as close as Mars. It reached peak brightness on 24 February, when it could be seen passing close to Saturn, but should remain visible in the sky until mid-March. The close pass gives astronomers their first chance to analyse the comet’s constituents, says Jenny Carter from the University of Leicester, UK. Images of Lulin taken
by NASA’s Swift telescope (see image, right) should help determine the comet’s exact chemical composition. The blue colour shows the presence of hydroxyl ions – formed when water breaks down – and the red is where the solar wind is interacting with material from the comet. Gary Kronk, an amateur astronomer from St Jacob, Illinois, recommends using a small pair of binoculars to look at the comet, which has an unusual double tail.
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Tax space cowboys SPACE junk has so far evaded even the most imaginative of tax collectors. But fining offenders could slash orbital debris. The hazard posed by debris was shown on 10 February, when a defunct Russian satellite destroyed
‘Alps’ under Antarctica
“Quote to go in here over four lines range left like this Quote to go in her like this xxxxx”
“Space tidiness could be improved by fining those that do not dispose of satellites safely”
The existence of a mountain range the size of the Alps, 4 kilometres below the Antarctic ice sheet, was confirmed this week. Aircraft carrying ice-penetrating radar established that the Gamburtsev mountains are rugged, with deep valleys and steep peaks. This suggests that they formed relatively quickly as the vast East Antarctic ice sheet ploughed over them.
Shoot for the moon
a US communications satellite. Such collisions can be avoided if nations dispose of satellites safely, either by parking them in “graveyard” orbits or burning Rosy outlook them up in Earth’s atmosphere. FLUORESCENT pink strips are But take-up of these methods is helping to save albatrosses and far from universal. petrels from extinction. An international framework Baited hooks on the long to fine countries that fail to do fishing lines used to catch tuna this would encourage tidier and swordfish snag and kill some habits, suggest Andrew Bradley 100,000 albatrosses and petrels and Lawrence Wein of Stanford University in California (Advances worldwide a year. In a bid to reduce this toll, the UK charity in Space Research, DOI: 10.1016/ Albatross Task Force tied pink j.asr.2009.02.006). Any money strips to the fishing lines used by collected could go into a fund to the long-line fishing fleets roaming compensate owners of satellites South African waters throughout damaged by debris, or be used to research cheaper ways to de-orbit “The pink strips reduced satellites, they say. petrel and albatross deaths “On the surface, it’s a very from long-line fishing by appealing idea, but the devil’s 85 per cent” in working out the details,” says Henry Hertzfeld of George 2008. The idea was for the strips Washington University in to frighten off the birds, stopping Washington DC. them from becoming entangled and drowning. They found that only 153 petrels and albatrosses were killed by the long-line fishing fleets that year – an 85 per cent reduction on 2007. “They form a visible deterrent and a no-go zone close to the bait and fishing gear as it’s reeled out,” says Graham Madge of the Royal Society for the Protection of Birds, a UK charity. The strips are only needed for 150 metres of the line before it is submerged and the bait sinks to depths of up to 60 metres, beyond –What’s in a comet?– the birds’ reach.
–Albatrosses avoid pink–
The task force wants countries to make bird conservation a legal obligation. Last year, a new South African law stated that vessels killing 25 or more birds would lose their licence. The method should help fishing fleets comply with the law. The strips are reusable and cheap, costing about $200 per ship, and don’t deplete the haul, says Madge.
Carbon satellite lost IT WAS designed to solve a longstanding mystery about missing carbon dioxide, but as New Scientist went to press, NASA’s new climate satellite seemed to have gone AWOL itself. The Orbiting Carbon Observatory (OCO) was designed to monitor exactly where and when CO2 is being emitted and absorbed. Of the total CO2 emitted by humans since the Industrial Revolution, roughly a third is known to have ended up in the atmosphere and a third in the oceans. The rest is missing – probably in carbon sinks on land. The OCO was supposed to have shown where. The mission failed, says NASA. The rocket lifted off on 24 February from a California base, but later data suggested that the fairing – intended to reduce drag – failed to separate, meaning the satellite did not reach orbit. NASA suspects it fell into the ocean near Antarctica.
India has announced plans to send two astronauts into space by 2015. The low-orbit mission will cost £1.7 billion and would put India alongside the US, Russia and China as the only countries to have sent a human into space. Indian space officials say that their ultimate goal is to go further than the moon, which will require crewed as well as robotic missions.
China blames the west A third of China’s carbon emissions come from making goods for export, especially to the US and UK. Such emissions are not its responsibility, says China’s government, which is under pressure to curb greenhouse gas emissions.
Fat, cigs and early death Being obese at 18 is as dangerous as smoking. Each doubles the risk of an early grave, according to a study in the BMJ of 45,000 Swedish men (DOI: 10.1136/bmj.b496). Obese 18-year-olds who also smoked heavily are five times as likely to die early as their non-smoking peers of normal weight.
Cheaper sequences? A tiny pore that detects electrical changes as a strand of DNA passes through it could provide cheaper DNA sequencing as it avoids using imaging tools. Pores made by UK firm Oxford Nanopore Technologies can distinguish between the four DNA bases, and bases with chemical “caps” (Nature Nanotechnology, DOI: 10.1038/NNANO.2009.12).
28 February 2009 | NewScientist | 5
Forensic evidence goes on trial Linda Geddes, Denver, Colorado
LAST month, Steven Barnes was exonerated of the rape and murder of a 16-year-old New York schoolgirl in 1985. Barnes had been convicted of these crimes on the basis of forensic evidence, including testimony that soil on his truck tyres matched that at the crime scene. An imprint on the outside of his truck also supposedly matched the pattern of the jeans the victim was wearing when she was killed. But this year, tests showed that DNA samples from the murdered girl’s body and clothing did not match Barnes’s, and he was freed after spending 20 years in jail. The US National Academy of
“The report helps show why so many innocent people get convicted in the US based on junk science” Sciences fears that miscarriages of justice like Barnes’s original conviction are all too common. In a highly critical report on the state of forensic science in the US, published last week, it questions the reliability of using techniques like hair or fingerprint analysis to link a person to a crime. The report was welcomed by delegates at a meeting of the American Academy of Forensic Sciences in Denver, Colorado, last week. “I think it’s long overdue,” says Michael Baden, chief forensic pathologist for the New York state police. “It brings criticisms of why so many innocent people get convicted in this country based on junk science.” It is also the first 6 | NewScientist | 28 February 2009
independent review to lay out guidelines on how forensic evidence should be collected and analysed, and is likely to have global ramifications, says lawyer and forensic scientist Judith Fordham of Murdoch University in Perth, Western Australia. But while forensic scientists agree that their discipline is due an overhaul, and indeed several are trying to make traditional techniques more robust (see below right), some say the report’s recommendations do not go far enough. “A lot of them are naive,” says Peter De Forest of John Jay College of Criminal Justice at the City University of New York. At the heart of the problem is the absence of scientists at the front line of investigations, De Forest says, yet the report fails to address this. It is scientists who should determine which tests are most appropriate for a particular crime scene, he says. At present it is left to police officers and prosecutors to decide. Also at fault is the system that allows prosecutors to bring expert witnesses into court to interpret evidence that they have had no hand in collecting. “In some of the wrongful conviction cases it wasn’t the scientist who got it wrong, it was the prosecution that misinterpreted it,” says De Forest. Other forensic scientists are worried that the report’s heavy criticism of the way traditional techniques are used will lead to them being wrongly dismissed in favour of DNA evidence. Many traditional methods “are getting short shrift”, says Brian Gestring of Cedar Crest College
When a suspect’s fate rests on evidence from the scene of a crime we need to know how reliable it is
Analysts claim they can identify how a bloodstain was created – by dragging a dead body, say – just by looking at it. But how reliable is this technique? Brian Gestring of Cedar Crest College in Allentown, Pennsylvania, asked 92 professional analysts and 65 non-experts to pinpoint how 10 different blood patterns were made. The experts got it right 97 per cent of the time, and lay people 21 per cent. The study is the first step towards being able to quantify an error rate that jurors could be presented with when hearing evidence in court. Now Gestring wants to put experts’ abilities to the test in mock crime scenes. These experiments are not making Gestring popular. “Some examiners were really angry with me,” he says.
Human hair is often shed at crime scenes. While DNA typing can help trace it to an individual, this is timeconsuming and expensive. Instead, analysts scrutinise hairs under the microscope, looking for features that establish a visual match between two samples. Julie Barrett and her colleagues at Indiana University in Indianapolis have investigated how dyes affect the way hair absorbs different ultraviolet wavelengths. Her method could add weight to a visual match between two hair samples. “Because there’s a tangible spectrum, we can put some numbers to it,” she says. But this technique could not be used in isolation, as hair from the same person can absorb dye to different degrees, complicating the analysis.
In this section ■ Are we ready to tweak Earth’s thermostat, page 8 ■ Ovaries get more youthful with age, page 11 ■ Anthrax attack evidence revealed, page 13
FINGERPRINTS Analysing the whorls and eddies of our fingerprints is the grandaddy of forensic techniques, but it has come under heavy criticism in recent years. Fingerprint analysts have “been the authors of their own misfortune by saying that there’s no error rate”, says Judith Fordham of Murdoch University in Perth, Western Australia. As with bloodstain analysis, no one knows how often analysts make mistakes. “The question that needs to be asked is not whether or not fingerprints are unique, but whether or not the examiner can tell them apart,” says Fordham. She would like to see blind testing of analysts to assess error rates, using prints from real crime scenes. “They’re just going to have to come up with the numbers and the stats.”
in Allentown, Pennsylvania, who amount of biological evidence points out that such techniques has been left behind. Yet even can still play an important role DNA evidence may not be in investigations – provided they unequivocal. It too is open to are interpreted properly and not interpretation, and there have been relied on uncritically. cases where it has gone wrong. “If I went to a crime scene and Both the report and its critics collected a blood sample from agree on one point: the reliability under a bleeding victim, I don’t of many forensic techniques know that I’d need $100,000 of urgently needs to be quantified. DNA testing to tell me it’s the “A lot of the techniques used victim’s blood,” Gestring says. “The reliability of many “What I would need to do is look long-standing forensic at the pattern of the blood to see techniques urgently needs if it was consistent with it being to be quantified” the victim’s blood.” While Gestring accepts that DNA can be extremely helpful today are valid with certain in a minority of cases, “it is caveats, but we need to go back not a panacea”, he says. The and lay that sound foundation belief in DNA’s infallibility so these data are more reliable,” sometimes means that DNA says Bruce Goldberger, a forensic testing “happens at the expense toxicologist at the University of of all the other evidence, when Florida, Gainsville. more often than not it can say Achieving this will not be more than the DNA”. easy. How, for example, do you In fact, DNA is only helpful in determine error rates for around 10 per cent of murder cases, subjective judgements about says Baden, and even in these how a strand of hair looks? This cases there is usually plenty of has led many analysts to argue other evidence as well. Where it that there is no error rate for can be extremely useful is in rape techniques like hair or fingerprint –Telling clues – if we read them right– and sexual assaults, where a large analysis, which claim to be able to find unequivocal matches between samples. “I don’t FIRE TOOL MARKS subscribe to that,” says Gestring. Fire investigators hunting for Marks left by the tools of a criminal’s “Even computers have error rates. evidence of arson look for the trade can give the culprit away. Let’s find out what they are.” residues of flammable liquids in fire Using a screwdriver to prise open a In many areas of forensic debris. A profile generated by gas window, for example, should leave evidence, scientists are beginning chromatography-mass spectrometry scratches unique to the tool. to do just that. Yet the tests are not (GCMS) can then be matched to a “It’s kind of up in the air as to how the only source of error, says John reference database. many lines make a match,” says Lentini at Applied Technical Unfortunately, the comparison is Nicholas Petraco of John Jay College Services in Marietta, Georgia. He visual, and therefore subjective. The in New York City. “Let’s see if we can wants forensic testing to take a speed at which the fire burns can put some numbers behind it.” lead from drug testing, where change the signature too. For Petraco, this means taking those running a trial are “blinded” To make analyses more robust, measurements of lines, features to details about the drug or Jamie Baerncopf of Michigan State and the topography of tool marks, patient. “We need to control University, East Lansing, and her and feeding them into statistical expectation bias,” Lentini says. team are running profiles generated algorithms that produce plots in Despite the criticisms levelled by GCMS through statistical which data points appear in clusters. against it, the NAS report has been algorithms. This allows them to draw The more similar the patterns, the widely welcomed as a reminder a confidence interval around the tighter the cluster. He has analysed to those working in fields like data from a known ignitable liquid. lines from nine screwdrivers, so far, fingerprints or ballistics that they An analyst could be “95 per cent and can match them with an error need to do better. “They’ve been confident that anything within this rate of 3 per cent. This should fall as very slow to come to the party,” circle is this liquid,” says Baerncopf. he adds more measurements. says Fordham. “Now they’re going to have to.” ■ 28 February 2009 | NewScientist | 7
SPECIAL REPORT / GEOENGINEERING
EARTH’S PLAN B
We may soon have no choice but to fiddle with the climate — but are we ready, asks Catherine Brahic
IN A room in London late last year, a group of British politicians were grilling a selection of climate scientists on geoengineering – the notion that to save the planet from climate change, we must artificially tweak its thermostat by firing fine dust into the atmosphere to deflect the sun’s rays, for instance, or perhaps even by launching clouds of mirrors into space. Surely the scientists gave such a heretical idea short shrift. After all, messing with the climate is exactly what got us into such trouble in the first place. The politicians on the committee certainly seemed to believe so. “It is not sensible, is it? It is not a serious suggestion?” Had the question been posed a few years ago, most climate scientists would have agreed. But the mood is changing. In the face of potentially 8 | NewScientist | 28 February 2009
catastrophic climate change, the politicians and scientists all agreed that since cuts to carbon emissions will likely fall short we need to be exploring “Plan B”. Climatologists have hit a “social tipping point” says Tim Lenton of the University of East Anglia, UK. What’s more, respected scientists, including Nobel laureate Paul Crutzen, and groups such as the UK’s Royal Society, are already assessing the risks and benefits. Are we ready to try to turn down the thermostat? Who will have the authority to push the button? And what would happen if one nation or “There is no well-intentioned “green finger” single global individual decided to go it alone? Geoengineering schemes range from thermostat which will the low-tech, such as planting trees, to bring about sci-fi, such as placing mirrors in orbit universal between Earth and the sun. All would cooling” work either by diverting solar energy
away from Earth or by sucking carbon dioxide out of the atmosphere to dampen the greenhouse effect (see diagram, page 10). Previously, the idea of tweaking the climate in this way was anathema to most scientists. Apart from the technical challenges and environmental risks, many argued that endorsing the concept might scupper international negotiations for a post-Kyoto protocol to reduce global emissions. But it’s becoming clear that moves to cut global carbon emissions are too little and too late for us avoid the worst effects of climate change. “There is a worrying sense that negotiations won’t lead anywhere or lead to enough,” says Lenton. “We can’t change the world that fast,” says Peter Liss, who is scientific adviser to the UK parliamentary committee investigating
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geoengineering. Extraordinary measures may now be the only way of saving vulnerable ecosystems such as Arctic sea ice. What’s more, geoengineering could turn out to be relatively cheap. Early estimates suggest some schemes could cost a few billion dollars, small change compared to the cost of slashing emissions – estimated by former World Bank chief economist Nicholas Stern to be at least 1 per of global GDP per year. In his testimony to the UK politicians last year, John Latham of the National Center for Atmospheric Research in Boulder, Colorado, argued that all of the above reasons make it “irresponsible” not to examine geoengineering. While no one advocates deploying fleets of ships or launching space mirrors tomorrow, we need to know
Too little, too late to save the Earth from climate change
how Plan B is going to work, which means doing field tests. “If you wait for a climate catastrophe then you need to deploy fairly full-scale fairly quickly which means you won’t have time to look at the risks,” says Ken Caldeira of the Carnegie Institution of Washington in Stanford, California. Yet, as with genetically modified crops, field testing has already sparked public resistance. This has been made clear with the various attempts in recent years over ocean fertilisation experiments. In 2007, a commercial firm called Planktos announced a plan to dump iron filings into the ocean off the Galapagos Islands. More recently, a research ship set off to seed iron in the Southern Ocean. Both generated protests from environmentalists, such as ETC group, which feared they would damage ocean ecosystems. In many ways ocean fertilisation shows how other geoengineering schemes might be regulated. After the Planktos furore, the London Convention on marine pollution – ratified by over 80 countries – extended its remit to include geoengineering, and imposed a ban on commercial fertilisation. It has also announced its intention to strictly regulate scientific experiments. On 9 February, interested parties met to begin setting up experimental standards. Yet how we would implement geoengineering schemes on a global basis is less obvious, says lawyer David Victor of Stanford University’s programme on energy and sustainable
development. “Whether all governments would need to OK a scheme in international waters or outer space is unclear,” he says. “Who would decide? And who would be responsible for redressing any unintended consequences?” For an example of the problems that would need to be ironed out, take a look at one of the more mature geoengineering schemes that could provide us with instant cooling today – pumping sulphate particles into the atmosphere to reflect the sun’s rays back into space. If one country forged ahead, it could have detrimental effects on others. A 2007 study suggested sulphate sunshades could trigger catastrophic drought in some regions. “There would inevitably be winners and losers, as there is not a single global thermostat which will bring about universal and consistent cooling,” says David Santillo, senior research scientist at Greenpeace Research Laboratories in Exeter, UK. “By its very nature, if there is to be any purpose in geoengineering, it would have to exert an impact over a vast proportion of the planet.” Victor estimates only a handful of nations or groupings – including Australia, Brazil, China, India, Russia, the European Union and possibly Japan – have the capability to unilaterally deploy atmospheric sunshades. Only one of these has come close so far. In November 2005, Yuri Izrael, former vice-chair of the Intergovernmental Panel on Climate Change and head of the >
DUMP THE SUNSHADE AT OUR PERIL What happens if we tinker, then change our mind? Will all of humanity be doomed? Not necessarily. Most methods that absorb carbon dioxide would take decades to work so stopping them is unlikely to have sudden undesired effects. In the most worrying scenario, sunshades would be deployed then removed. Preliminary results suggest aerosols would naturally have a stratospheric life of
about one year, making them reversible if needed. But there is a big catch. If they were deployed as an excuse to continue burning fossil fuels, the masked greenhouse effect would build up and other effects such as ocean acidification would continue. Sunshades would have to be replenished or the planet would be hit with the full force of pentup warming. Victor Brovkin
of the Max Planck Institute for Meteorology in Hamburg, Germany, calculates that if a sunshade were kept up for 200 years, then dismantled, the planet could warm by between 5 °C and 10 °C within decades. Such an event would trigger massive belches of methane from thawing permafrost and the breakdown of entire ecosystems.
> 28 February 2009 | NewScientist | 9
SPECIAL REPORT / GEOENGINEERING Russian Global Climate and Ecology Geoengineering Geoengineeringweighed weighedup up Institute, tried to persuade his president, Vladimir Putin, that Russia should release 600,000 tonnes of AEROSOLS sulphur aerosol particles into the Particles in the stratosphere atmosphere immediately. SPACE MIRRORS reflect sun’s rays Orbiting mirrors deflect sun’s rays READINESS: If any nation seriously considered READINESS: COST: $ going it alone, “there would almost COST: $$$ FLAW: risk of ozone depletion; FLAW: unknown weather effects; certainly be an international diplomatic unknown weather effects, fails to prevent acidic oceans fails to prevent acidic oceans incident”, says Santillo. If a sunshade FORESTING triggered drought elsewhere, this could Trees absorb CO2 REFLECTIVE CROPS be interpreted as “hostile use” of READINESS: Planting crops that ARTIFICIAL TREES COST: $ weather modification, in which case the reflect more sunlight CO2 sucked from air and FLAW: large land READINESS: action would fall foul of the UN stored underground area needed COST: $ READINESS: Convention on the Prohibition of FLAW: large land area COST: $$$ Military or Any Other Hostile Use of needed; fails to prevent FLAW: large geological acidic oceans cache needed Environmental Modification Techniques (ENMOD). During the CLOUD SEEDING Vietnam war, the US experimented with Atomising seawater creates clouds to reflect sun’s rays rain seeding to disrupt the Ho Chi Minh READINESS: trail, which eventually led 70 nations, COST: $$ including the US, to ratify the treaty. But FLAW: unknown weather effects, patchy success; fails for it to be of any use, a drought-stricken to prevent acidic oceans nation would have to prove that a stratospheric sunshade was to blame and this could be difficult at best. “Almost everyone agrees that some form of international regulation and authorisation is necessary,” says John Shepherd, a deputy director of the UK BIOCHAR Tyndall Centre for Climate Change Agricultural carbon waste is burned and buried Research and chair of the Royal Society CARBONATE ADDITION READINESS: Ground limestone helps working group investigating COST: $$ oceans absorb CO2 FLAW: large land area needed geoengineering. But as for how, “we READINESS: COST: $$ just don’t know”, he says. FLAW: unknown effects OCEAN FERTILISATION The obvious choice would be for the on ecosystems Iron filings stimulate C02-eating plankton UN to regulate geoengineering. READINESS: However, when New Scientist enquired, COST: $$ FLAW: unknown effects on ecosystems the UN Framework Convention on Climate Change was unable to Cost: Cooling factor: Readiness: comment. According to Joan Ruddock, $ – Cheap relative to cutting emissions potential to – Within years $$ – Significant compared to cost of cutting emissions change Earth’s – Within decades a UK minister serving in the $$$ – Cutting emissions might be cheaper energy budget – Within centuries Department of Energy and Climate Change, a powerful UN treaty on Washington DC describes a gathering huge challenges. But living in a much geoengineering in the wake of failed he attended at NASA’s Ames Research warmer world will be even more emissions talks is unlikely. “If we have Center in California in November 2006. unpleasant (see page 28). For now we entirely failed to bring the world Astrophysicist Gregory Benford of the have time. It will be a couple of decades community together to do the rather University of California, Irvine, before we know if international simpler things which we already announced that he wanted to “cut negotiations to wean ourselves off high understand very well,” she says, then through red tape and demonstrate carbon fuels have had any success. devising a geoengineering agreement “Only fools what could be done” by injecting a If not, we may have no choice but would be even more difficult. find joy in chalk-like substance into the Arctic to start tweaking the climate ourselves. Even if no nation did go it alone and the idea of stratosphere to reflect sunlight, using “Only fools find joy in the prospect governments couldn’t agree on global climate private funding. And Planktos of climate engineering,” says Caldeira. action, that still leaves the alarming engineering. would have forged ahead with ocean “There is a sense of despair that we possibility of an individual deciding to fertilisation had no one stepped in. are not seeing deep emissions cuts modify the climate on their own – a so- There is a There is little doubt that planetary quickly, and that is pushing us to called “green finger”. Science historian sense of despair ” tinkering presents governments with consider these things.” ■ James Fleming of the Wilson Center in 10 | NewScientist | 28 February 2009
The curious case of the ageing ovaries Aria Pearson
YOUNG women with fertility problems caused by polycystic ovary syndrome may have reason to take heart. Over a lifetime their chances of having children appear just as good as other women’s, perhaps because egg production increases as they grow older. About 7 per cent of reproductiveage women have PCOS, which features irregular periods, high levels of male hormones and greater numbers of developing follicles, or cysts, on the surface of their ovaries. In a normal ovary, a few follicles appear each month, one or two of which mature and release an egg; the rest die off.
Fossilised fish are proof of ancient sex SEXUAL intercourse was far more common in early vertebrates than anyone imagined. So suggests a new study of ancient shark-like creatures called placoderms. Last year, John Long of Museum Victoria in Melbourne, Australia, and colleagues found an embryo complete with umbilical cord inside a placoderm fossil from the Gogo formation in Kimberley, Western Australia. This “mother fish” pushed back evidence of internal fertilisation and live birth by 200 million years to 380 million years ago. But how placoderms managed to mate, considering some orders could grow to be 6 metres long and all were heavily armoured, had been a mystery. Now, Long and a different team think they have the answer. They examined the pelvic anatomy of three 380-million-year-old placoderm fossils belonging to the order Arthrodira and found a previously unnoticed “extra long
Women with PCOS ovulate less often because their extra follicles interfere with normal hormonal activity and stop follicles maturing past a certain stage. This is how PCOS lowers fertility. Now it looks like that is not the end of the story. Miriam Hudecova and colleagues at Uppsala University in Sweden interviewed 91 women who were 35 or older and had been diagnosed with PCOS when younger. They found the women had undergone just as many pregnancies and borne as many babies, on average, as PCOS-free women of the same age. Some of the women with PCOS had been treated for infertility, but more
than two-thirds had become pregnant without such help. Hudecova also examined most of the women and found that the ovaries of the older women with PCOS showed signs of being more active, with better hormone levels and more eggs available, than those of control women of the same age (Human Reproduction, DOI: 10.1093/humrep/den482). “As they get older, the chance of
“As women with polycystic ovarian syndrome get older the chance of getting pregnant may be higher” getting pregnant may actually be higher,” says Hudecova. There may be an explanation for this. As women age, fewer follicles are produced each month, and in most this reduces fertility. With PCOS, however,
fewer follicles may have the opposite effect: it may stop the hormonal interference and cause follicles to release eggs normally. The hypothesis is backed up by other studies that have shown that the menstrual cycles of women with PCOS tend to become more regular as they age (Human Reproduction, vol 15, p 24). Marcelle Cedars, a reproductive endocrinologist at the University of California, San Francisco, points out that it also chimes with a recent finding that hormone treatments can coax immature follicles to produce eggs. “They might hit their reproductive peak a little bit later than other women,” says Richard Legro, a gynaecologist at Penn State Milton S. Hershey Medical Center in Hershey, Pennsylvania. “When we see more data to that effect we’ll revise what we tell them.” ■
bone” with “a long lobe projecting backwards”, says Long. The shape of the lobe indicates that it articulates with cartilage, similar to the erectile claspers of modern-day sharks, he says (Nature, DOI: 10.1038/ nature07732). These claspers would have been used to channel sperm into the female’s cloaca, a posterior opening also used for expelling waste, in a similar way to today’s sharks, says Long. The team also re-examined two other arthrodire fossils from the same region. Small skeletons inside the specimens had been thought to be the debris of a cannibalistic dinner. But Long’s team now thinks that they were growing embryos. “The fish bones and armoury were not broken and crushed, as you’d expect if they were stomach contents,” says Long. While the original “mother fish” was from an obscure placoderm order, the arthrodires are from the largest. This raises the question of whether sexual intercourse evolved once, prior to the orders branching off, or many times independently, says Gavin Young, an expert on fish evolution at the Australian National University in Canberra. Rachel Nowak ■ 28 February 2009 | NewScientist | 11
Camels, Heisenberg and quantum uncertainty WHAT does a biblical saying about a camel passing through the eye of a needle have to do with quantum uncertainty? Quite a lot, it turns out, since a mathematical concept called the “symplectic camel” promises to explain quantum uncertainty in simple classical terms. According to Heisenberg, it is impossible to measure both the momentum and position of a quantum particle accurately because those properties are interlinked. Measuring one therefore makes the other more uncertain. That’s because individual particles are considered parts of a probability “wave”, in which many possible
combinations of position and momentum exist simultaneously. But Maurice de Gosson at the University of Vienna in Austria thinks that the inability to pin a particle down is due to something called symplectic geometry, not “The point that there quantum weirdness. is, in effect, a ‘classical De Gosson realised that a uncertainty principle’, theorem in symplectic geometry had parallels with the uncertainty is extremely intriguing” principle. The concept is known as the symplectic camel after the uncertainty in measurement, not biblical suggestion that it is easier quantum fuzziness (Foundations for a camel to pass through the of Physics, vol 39 p 194). eye of a needle than for a rich That is encouraging for those man to get into heaven. who hope to recast quantum De Gosson imagined that a ball mechanics in a more deterministic represents a cloud of possible way. “The point that there is, in positions for a quantum particle. effect, a ‘classical uncertainty principle’, is extremely intriguing,” says Michael Hall of the Australian National University in Canberra, who has also worked on the uncertainty principle. However, it could be tricky to reproduce all the predictions of quantum mechanics using symplectic geometry, cautions Roderich Tumulka, who works on the foundations of quantum theory at Rutgers University in New Jersey. A key problem is whether an analogy like de Gosson’s represents a deep connection, or is simply a coincidence. John Norton, a philosopher of physics at the University of Pittsburgh in Pennsylvania, points out that de Gosson’s analogy fails to share one aspect of uncertainty with that of quantum mechanics. The uncertainty in position and momentum of a quantum particle is always greater than an amount represented by Planck’s constant, a fundamental quantity in the quantum world. In de Gosson’s derivation, the constant’s value is unknown. “The characteristic quantity of quantum theory has to be put in my hand,” says Norton. Eugenie Samuel Reich ■
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He found that such a ball cannot be squeezed down to the size of one particle to fit through a hole in a plane, because its geometry resists this in some way. The inability to squeeze the ball is analogous to singling out one particle and measuring its position and momentum exactly. De Gosson reckons this geometrical resistance creates the
“It was kind of like a religious conversion.” Stephen Tindale, former director of Greenpeace UK, explaining that he and other leading environmentalists now back nuclear power because of the urgent need to curb carbon dioxide emissions (The Independent, London, 23 February)
“My family believe my brother was murdered.” David Fielding, whose brother was one of 2000 British people with haemophilia who died after being given blood contaminated with HIV or hepatitis in the 1970s and 80s. Fielding gave evidence at an independent inquiry into the incident, which released its report this week (The Scotsman, Edinburgh, UK, 22 February)
“This was a digital rights grab.” Marc Rotenberg of the Electronic Privacy Information Center in Washington DC, which had planned to file a complaint with the Federal Trade Commission over Facebook’s change to its contract with users, which appeared to give it perpetual ownership of their contributions. Facebook reversed the changes on 17 February (The New York Times, 18 February)
“It’s just an SMS that’ll take 45 seconds to complete.” David Howman, director general of the World Anti-Doping Agency, which on Tuesday refused to make immediate changes to out-ofcompetition rules for drug testing. Some athletes object to a rule requiring them to notify drug testers of their whereabouts (AFP, 24 February)
“Why would the academy want to come after a little non-profit?” Kori Titus of Breathe California, host to the “Hackademy” awards, which rate films according to their portrayal of tobacco use. The Academy of Motion Picture Arts and Sciences is claiming copyright infringement (The Sacramento Bee, 19 February)
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four. One came from a flask labelled RMR-1029 that Ivins was responsible for at USAMRIID. The other seven came from cultures taken from that flask, only one of which was not located at USAMRIID. So while these findings show the attack spores came from one of these cultures, the FBI has gone further in concluding the attack came directly from the RMR-1029 flask. Another question is how the attacker turned the water-based slurry of spores in the flask to the fine, dry powder in the letters. Joseph Michael of the Sandia National Lab in Albuquerque, New Mexico, used specialised electron microscopy to show that 75 per –The chief suspect committed suicide last year– cent of the attack spores had incorporated silicon into their coats while growing (see image, been found were misleading. The below). As spores taken directly full genome sequences revealed “no genetic differences at all”, says from RMR-1029 following the Keim. Instead, the researchers say, attacks had no silicon in their coats, and the other seven genetic the key clues came from a lucky matches had either none or a discovery. A technician, also at USAMRIID, had noticed patches “The researchers say their the anthrax bacterium used in of unusual-looking spores in investigations only nail the attack as the US army’s Ames cultures of the attack anthrax, the source of the anthrax strain. The FBI then obtained 1072 and recultured just those. Keim and colleagues sequenced their spores, not the attacker” anthrax samples from the 18 labs genomes and found 10 mutations it knew to have Ames and got several research groups, including that differed from the common lower percentage, the attack Keim’s, to compare their genomes Ames sequence. Because the spores must have been recultured before they were posted. spores made up a fraction of the with that of the strain used in the During this process, they would total, these “minority” mutations attacks. The hope was this would have shed their coats, multiplied, hadn’t shown up initially. uncover mutations that would then turned back into spores. Was Next the team developed finger one lab as the source. Ivins’s level of expertise needed to But Keim and his colleagues told highly sensitive tests to screen turn these recultured spores into the Baltimore meeting that initial all 1072 samples for four of the dry powder? “What I am hearing reports that useful mutations had mutations. Eight samples had all is that the spores in the letter were not special. It would not take a lot Spore clues of time or equipment to make Electron microscopy of the anthrax sent to media outlets and politicians in 2001 provided vital clues to how the them,” says Keim. Michael’s spores were prepared images show the attack anthrax The attack samples contained clumps of Silicon incorporated into the coats of the contained spore clumps, unlike spores, suggesting they had not been attack spores shows that they were professionally produced powders. professionally produced recultured before being posted The FBI may have evidence to show Ivins was the link between RMR-1029 and the envelopes, though with civil suits from Ivins’ and the victims’ families pending, the bureau won’t be revealing it soon. For now, the researchers say their studies nail the spores as coming from the flask, but not 5 μm 1 μm the identity of the attacker. ■
KEY forensic evidence in the US anthrax attacks of 2001 has been revealed. The FBI had previously prevented the scientists involved from speaking publicly about their findings in case this interfered with court proceedings, but last August, after chief suspect Bruce Ivins committed suicide, the case collapsed and the FBI lifted many of the restrictions. This week, some of the scientists involved revealed their results at a scientific meeting in Baltimore, Maryland. These show how the FBI traced the spores used in the attacks to a single flask at a US government lab, but they don’t explain why the FBI made Ivins – who worked at the US Army Medical Research Institute for Infectious Diseases (USAMRIID) – the chief suspect. In late 2001, envelopes containing dry anthrax spores were sent to a number of US media outlets and politicians, leading to five deaths. Later that year, Paul Keim at the Northern University of Arizona in Flagstaff identified
SOURCE: SANDIA NATIONAL LABORATORY
Behind the 2001 anthrax attacks
28 February 2009 | NewScientist | 13
IN BRIEF Live near fast food, up your stroke risk
Supercell signal warns if tornado is on the way TORNADO hunters may have a new ally – electricity. Armed with only an antenna and a receiver, Ernst Schmitter of the University of Applied Sciences at Osnabrück in Germany and John Leeman from the Leeman Webb Storm Laboratory in Norman, Oklahoma, picked up low-frequency electromagnetic waves in a rotating storm known as a “supercell”. About 30 per cent of these storms spawn tornadoes. Schmitter and Leeman believe it is the supercell’s swirling action that generates the signal. When dust particles and droplets within the storm rub against
each other, they become oppositely charged. The lighter particles, which are mostly negative, get blown to the top of the funnel, while the heavier, positive ones sink to the bottom. As the separated particles rotate around the vortex, they emit low-frequency electromagnetic radiation (Atmospheric Research, DOI: 10.1016/j.atmosres.2008.10.029). This will improve tornado detection, which usually relies on teams of spotters and weather radar. Such methods can fall down in poor visibility, or when clouds or heavy rain block the microwaves used in radar. In contrast, low-frequency radiation can penetrate further through cloud and rain than microwaves. What’s more, an electromagnetic signal could be picked up instantly, whereas it takes time to refresh each radar scan.
Giant flying dinos had built-in airbags NOW we know how pterosaurs could once rule the skies. The biggest animals ever to fly had super-efficient bird-like lungs. Leathery-winged pterosaurs evolved 220 million years ago from the same group of reptiles that gave rise to crocodiles and, later, birds. How the animals with 10-metre wingspans powered their flight had been a mystery because they were thought to 14 | NewScientist | 28 February 2009
have inflexible ribcages, which would have made their breathing too inefficient for such exertion. Leon Claessens at the College of the Holy Cross in Worcester, Massachusetts, realised this view might be mistaken after pterosaur specialist Dave Unwin at the University of Leicester, UK, showed him a pterosaur fossil that suggested a “mobile ribcage”. Further fossils confirmed it.
What’s more, the fossils revealed that the hollow bones contained air sacs linked to the dinosaur’s lungs. As in birds, such sacs would have passed air back and forth through the lungs, extracting oxygen more efficiently than in mammals. Intriguingly, the sacs were connected to a pneumatic system under the skin, which pterosaurs might have been able to inflate to adjust their wing shape, Claessens says.
PEOPLE who live in areas with many fast food restaurants are more likely to have a stroke than those living on healthier streets. So say Lewis Morgenstern of the University of Michigan in Ann Arbor and colleagues. They divided Nueces county, Texas, into 64 areas of roughly equal population and found that between 2000 and mid-2003, there were 13 per cent more strokes in areas with an average of 33 fast food restaurants than in those with just 12 fast food joints. Accounting for factors such as socio-economic status, they calculate that each additional restaurant ups the risk of stroke by 1 per cent. Fast food restaurants may not be behind the high rates of stroke, says Morgenstern, who presented the study at the American Heart Association’s International Stroke Conference. They may just indicate other risk factors.
Born to look on the bright side A TENDENCY to seek out positive information may be in your genes. Elaine Fox at the University of Essex, UK, asked people to say which side of a screen target dots were on. Before the dots appeared, one side of the screen showed a positive or negative image and the other a neutral one. The time taken to spot the dots indicated which image was being looked at. People with two copies of a certain gene took longer to spot the dots when they appeared on the same side as a negative image compared with the neutral image, and less time when they were on the side of a positive image. It shows they focus on positive images and resist negative ones (Proceedings of the Royal Society B, DOI: 10.1098/rspb.2008.1788).
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BEAUTY is in the brain of the beholder: it seems the brains of men and women respond differently to beautiful landscapes. This may stem from the varied evolutionary pressures on the two sexes in our hunter-gatherer ancestors. A team led by Camilo Cela-Conde of the University of the Balearic Islands in Palma, Majorca, Spain, asked males and females whether photographs of natural and urban landscapes were beautiful or not. When they looked at a scene they deemed beautiful, both men and women had greater electrical activity in the parietal region, near the top of the brain. In women, this activation occurred in both halves of the brain, but in men it was restricted to the right hemisphere (Proceedings of the National Academy of Sciences, DOI: 10.1073/pnas.0900304106). This might reflect evolutionary differences, the team suggest. In early humans, they say, men were hunters who needed mental maps of distance and direction, while women gathered plants for food and oriented themselves using landmarks. This fits with data that the left brain handles “categorical” spatial relations, such as landmarks, while the right evaluates “coordinate” data, such as distance and direction. The team say that what we find beautiful may have evolved from what our ancestors looked for in a habitat.
Childhood abuse may leave ‘suicide marks’ on genes CHILD abuse appears to leave chemical “caps” on victims’ genes that last into adulthood and which may help to trigger suicide. Last year, Michael Meaney and his colleagues at McGill University in Montreal, Canada, found that in people who had been abused and later committed suicide, more genes were “switched off” in brain tissue taken from the hippocampus – a region involved in mood control – compared with people who had not been abused and who had died in other ways. To see if these differences might
be linked to the abuse itself or to suicidal tendencies in general, the team has now compared samples of hippocampal tissue from 24 people who killed themselves – half of whom were abused or neglected as children, half of whom were not – and from 12 people who were not abused and who died in other ways. The people who had both been abused and committed suicide had more chemical caps on their Nr3c1 gene, compared with the other groups. Nr3c1 is thought to help modulate the response to
stress. They also had lower levels of the messenger RNA that corresponds to the expression of Nr3C1, indicating that the caps had suppressed the gene (Nature Neuroscience, DOI: 10.1038/nn.2270). This suggests the changes in gene expression is linked to childhood abuse or neglect, and not to suicide. However, as people who were abused are more likely to kill themselves, Meaney suspects that the gene changes due to abuse may in turn predispose people to suicide. BRUNO ANDREOTTI/THE MORPHODYNAMICS LAB
What makes for a sexy landscape?
Spotted in space, picked up on Earth IT’S been an extraordinary trip for space rock 2008 TC3. First spotted on 6 October hurtling through space towards Earth, it exploded over Sudan the next day. Now tiny pieces of it have been found. The discovery means that, for the first time, we have detected a space rock ahead of a collision with Earth, watched it streak through the atmosphere and then recovered pieces of it. According to Lindley Johnson of NASA, who reported the find on 16 February at a United Nations meeting in Vienna, the rocks were found in the Sudanese desert by a team from the University of Khartoum. They have an outer crust of singed material characteristic of meteorites. Most meteorites are thought to be pieces of asteroids, but pinning down exactly where they came from is usually impossible. Fortunately, 2008 TC3 was observed while still in space. “It’s often very difficult to get from a streak in the sky to what the orbit was,” says Allan Treiman of the Lunar and Planetary Institute in Houston, Texas. “But if they’ve got its location before it hit the atmosphere, they’re far better off – that’s really wonderful.”
Warmer Earth equals bigger dunes AT 500 metres tall, Earth’s largest sand dunes are already monsters – yet they are set to grow bigger as the world warms. Giant sand dunes are thought to form when smaller dunes crash into each other and pile up. To investigate if anything limits their size, Bruno Andreotti at the Denis Diderot University, Paris, and colleagues calculated what the atmospheric flow looks like around giant dunes. They found that the thickness of the lowest layer of the atmosphere – the boundary layer – controls dune size, with a thicker layer leading to larger
dunes (Nature, vol 457, p 1120). “Once the dune becomes big enough to interact with the boundary layer it creates waves in the air. These waves feed back and interact with the sand below, keeping a lid on the dune size,” explains co-author Brad Murray of Duke University in Durham, North Carolina. Warmer air increases the thickness of the boundary layer, which explains why Earth’s largest dunes are found inland, in the hottest part of the desert. It also suggests that if global warming heats the planet in the right place, then dunes could get bigger.
28 February 2009 | NewScientist | 15
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FOCUS FEATURES/2008 LAIKA INC
Animated movies spring to life A 3D printer – a machine that “prints” small objects rather than pages – has been used for the first time to give the characters in an animated movie a far greater range of facial expressions than has been possible before. When fed with a design from a computer, a 3D printer gradually builds up objects by depositing layer upon layer of material. The materials can be plastic, nylon or metal powders, and each layer is set hard by a blast from a laser before the next one is laid down. These devices, which are mainly used for prototyping products, offer major advantages over the traditional techniques for making the models used in stop-motion films like Wallace & Gromit. Rather than painstakingly hand sculpting every facial expression, animators can instead 3D print many slightly different heads, says Martin Meunier, the “creature
supervisor” at Laika Entertainment in Portland, Oregon. The company made the animated movie Coraline, which opened in the US this month. By laying down layers just 16 micrometres thick – far finer than a human animator could sculpt – the printer offers greatly increased
“3D printers allow animators to capture almost a quarter of a million facial expressions” subtlety. This allows animators to capture almost a quarter of a million fine-grained facial expressions. “When you look at a lot of the models’ faces side by side you often can’t tell them apart,” Meunier says. “But when they are projected onto a cinema screen their subtle expressions really come alive.”
–Coraline’s models were printed layer by layer–
Website will dish the dirt on foods IS IT best to buy local produce grown in a greenhouse or an imported alternative? Shoppers will soon have a powerful tool to help answer such conundrums: www.goodguide.com. On 9 March, the San Franciscobased website will add food from supermarkets around the globe to its existing roster of consumer safety and carbon-footprint ratings for non-food goods. If a food product has a barcode, GoodGuide promises to rate it, revealing what it contains in terms of chemicals, colourings, additives and nutrition, as well as its environmental impact. “You could take 12 hours on 50 different sites checking animal rights, worker rights, anti-GMO sites or anti-irradiation sites. We aggregate all these issues in one place,” says GoodGuide’s founder Dara O’Rourke.
Robots can’t tell friend from foe
The number of cellphone chargers a household will need by 2012, when a universal device becomes available
THE idea that robots might one day be able to tell friend from foe is deeply flawed, says roboticist Noel Sharkey of the University of Sheffield in the UK. He was commenting on a report calling for weapon-wielding military robots to be programmed with the same ethical rules of engagement as human soldiers. The report (www.tinyurl.com/ roboshoot), which was funded by the Pentagon, says firms rushing to fulfil the requirement for onethird of US forces to be uncrewed by 2015 risk leaving ethical concerns by the wayside. “Fully
autonomous systems are in place right now,” warns Patrick Lin, the study’s author at California State Polytechnic in San Luis Obispo. “The US navy’s Phalanx system, for instance, can identify, target, and shoot down missiles without human authorisation.” While Sharkey applauds the report’s broad coverage of the issue, he says it is far too optimistic: “It trots out the old notion that robots could behave more ethically than soldiers because they don’t get angry or seek revenge.” But robots don’t have human empathy and can’t exercise judgement, he says, and as they can’t discriminate between innocent bystanders and soldiers they should not make judgements about lethal force.
“Whoever is hacking, please stop doing that” Peter Sunde of the Pirate Bay website appeals on Twitter.com for hackers to stop defacing the website of the International Federation of the Phonographic Industry which, alongside movie studios, has taken Pirate Bay to court for alleged copyright breaches (Twitter, 18 February)
28 February 2009 | NewScientist | 17
Projector phones: cool app or visual pollution? IF HEARING other people’s music fizzing out of tinny headphones annoys you, get ready for even more irritation: chip maker Texas Instruments (TI) has shrunk a video projector to the size of a raisin and it says the device is cheap enough to become the next must-have feature for cellphones. This means people could project their photos, videos and Powerpointstyle presentations on walls, tables or just about any other surface. But while specialists see some advantages in the technology, particularly in creating new ways to interact with cellphones, they also warn that it raises fresh privacy and security issues.
What’s fuelling projection’s move to the cellphone is the ongoing miniaturisation of the chips TI already uses in projection TVs. These digital light processing (DLP) chips contain thousands of electromechanical mirrors that each represent a pixel. When a
is called the DLP Pico and has a resolution of 480 by 320 pixels. That chip is now being used in pocket-sized portable projectors and was launched in a cellphone for the first time at last week’s Mobile World Congress in Barcelona, Spain. This Samsung phone lets users “Just as BlackBerry brought project an image about 1.3 metres email to the restaurant wide. However, the device is table, this might bring us unlikely to achieve mass adoption Powerpoint presentations” because of its low resolution. So last week TI also launched pixel is to be illuminated, an a second-generation chip with electric field causes the mirror to a resolution of 850 by 480 pixels – tilt, sending light from red, green the same as a DVD player. and blue LEDs in turn to a lens That kind of resolution is what and then onto a screen. cellphone makers have been Last year, TI launched the first asking for, says Frank Moizio micro-scale projector chip, which of TI in Austin, Texas.
Three shakes and your phones are connected With the recession biting, the Mobile World Congress in Barcelona, Spain, last week was short on ground-breaking technological ideas. Cellphone-makers largely made the best of their existing product lines instead. Yet they are still filing patents on innovations for when the good times return – and Nokia reckons gestureactivated communication could be one of them. Its idea, in US patent application 2009/0031258, is that if groups of friends want to, say, swap photos, they can connect their cellphones via Bluetooth using a series of gestures as a password – instead of having to work through on-screen menus. The technology hangs on the fact
that many phones now have motion sensors: when held sideways, for example, a phone might show a web browser in landscape format, then revert to portrait when it is righted. The patent describes software allowing users to record a short, unique sequence of movements – such as shaking to the left three times followed by a sharp upward move – that lets their phones link up. It’s a kind of tech-mediated Masonic handshake for people who wish to sidestep increasingly complex phone menus, say the inventors. The idea is still in the concept stage, says Frederique Sleazak of Nokia’s lab in Espoo, Finland – and the firm has not committed to launching it any time soon.
Despite increasing the number of mirrors from 150,000 to over 400,000, the new chip is 20 per cent smaller – making it much more practical for cellphones. “We achieved that by figuring out how to reduce the border area around the mirrors on the chip and optimised the way we connect them electrically,” says Moizio. ALEXIS MARYON/PYMCA/REX FEATURES
The next technology to be installed in cellphones looks likely to be the video projector. But will anyone want or use them?
–It’s the gesture that counts– 18 | NewScientist | 28 February 2009
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Mega-laser to probe secrets of extrasolar planets
might emerge. For instance, we don’t hear as many annoying ringtones as we used to,” he says. One privacy and security risk that must be addressed, he says, is accidental or malicious projection of somebody’s personal information, such as bank details. Robert Caunt, an analyst with market researcher CCS Insight in London, thinks the technology will let us in for more “death by Powerpoint” – poorly produced, overlong, special-effects laden presentations. “Just as the BlackBerry brought email to the restaurant table, this could bring us impromptu presentations we might rather not have,” he says. ■
discovered in the last two decades. “The chemistry of these planets is completely unexplored,” says Jeanloz. “It’s never been accessible in the laboratory before.” Next year, Livermore teams will start work on experiments that could ultimately have an even bigger impact. They will use the lasers to ignite a fusion reaction in a ball of hydrogen isotopes. Other labs have triggered fusion, but not a selfsustaining reaction. The Livermore facility should deliver a big enough jolt of energy to trigger a reaction that burns until the fuel is used up. The data produced will feed into attempts to design a commercial fusion power plant. The same reaction will also aid the management of the US nuclear
“It can deliver 500 trillion watts in a 20-nanosecond burst – opening up new scientific possibilities” weapons stockpile. It is more than 15 years since the US tested a nuclear weapon. Engineers use computer simulations to determine if warheads are in working order, but the models need to be calibrated using data from experiments like NIF’s fusion reactions. Jim Giles, San Francisco ■ NIF
In most lighting conditions you can get a good image the size of a sheet of A4 paper, Moizio says. And power use is low enough for one battery charge to show a 2-hour movie. So if cellphone makers adopt the new chip en masse, and Samsung’s rivals Microvision, Motorola and 3M launch the projector phones they have promised, will people actually use them? And if so, how? At the University of Lancaster, UK, mobile interaction specialists Enrico Rukzio and Andrew Greaves have been researching just that. Rukzio thinks the dim image is going to be an issue that hints at more youthful, informal uses. “In a darkish pub, photos and video look great projected on the ceiling – and fine, too, on the side of a house at night. So I think teenagers will be the first adopters,” he says. In research the pair presented at the Mobile Human Computer Interaction conference in Amsterdam, the Netherlands, last September, Greaves says the ability to have two screens – a tiny one on the phone and a large one on the wall – proved compelling for their group of volunteers (www. tinyurl.com/projpix). “They could keep personal info on
AN AWESOME laser facility, built to provide fusion data for nuclear weapons simulations, will soon be used to probe the secrets of extrasolar planets. The National Ignition Facility (NIF) at the Lawrence Livermore National Laboratory in California was declared ready for action earlier this month. Its vital statistics reveal it to be a powerful beast: its ultraviolet lasers can deliver 500 trillion watts in a 20-nanosecond burst. That power opens up new scientific possibilities. For instance, Raymond Jeanloz, an astronomer at the University of California, Berkeley, will use the –Cellphone cinema– device to recreate the conditions inside Jupiter and other larger planets, where pressures can be the phone and public content, like pictures or maps they wanted 1000 times as great as those at the centre of the Earth. to talk about, on the projection.” Jeanloz will fire the lasers at an iron There are downsides, though. sample 800 micrometres in diameter. “This is a promising, positive The intense heat will vaporise the technology if used in the right metal, generating a gas jet so context. If not, there could be powerful it will send a shock wave a lot of visual pollution,” warns through the iron, compressing it Greaves. “People could screen to over a billion times atmospheric material on a bus, say, that could be indecent – and that might even pressure. By measuring how the metal’s crystalline structure and lead to the need for legislation.” melting point change at these Rukzio thinks that after a few initial transgressions people may pressures, Jeanloz hopes to shed light on the formation of the hundreds of self-adjust: “Some kind of social giant exoplanets that we have protocol about public projection
–Nuclear spark plug– 28 February 2009 | NewScientist | 19
Golden ‘nanonets’ conduct themselves in an orderly way… THE rings left behind by spilled coffee have inspired a new way to make ultrathin coatings for LCD and plasma flat-screens. In LCDs, transparent conductive coatings are used to form an electrode on the surface of the screen, while in plasma TVs they provide a shield that prevents electromagnetic fields from straying. The traditional techniques for making such coatings include sputtering a fine layer of indium tin oxide onto the surface. ITO is highly conductive and transparent to visible light, but the process is expensive, requiring clean rooms and vacuum chambers. Ivan Vakarelski at the Institute of Chemical and Engineering Sciences in Singapore realised that coffee stains could point the way to a cheaper alternative. Spill coffee and the evaporating liquid drives coffee particles to the edges of the spill – which ultimately produces the circular stain. The
coffee granules are being “assembled” by the varying evaporation and convection rates in the fluid. Vakarelski and his colleagues figured that if they could mimic the process in a controlled fashion, they could create a pattern of granules of other materials to form a nanoscale conductive coating. Instead of coffee, they started with a suspension of gold particles, each about 20 nanometres across. The suspension was left to dry on a glass plate covered
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could make even better conductors than ITO coatings. The team has made coatings a few square centimetres in size in the laboratory and aim to increase this tenfold. Unlike many new technologies, the nanonet process will be easy to scale up, says Vakarelski. The work has “considerable merit”, says Jennifer Lewis at the University of Illinois at UrbanaChampaign, an expert on the selfassembly of nanoparticles. “A key advantage of their approach is that the resulting networks are semi-transparent and their density can be tuned by varying the size of the [latex-microsphere] template.”
As the liquid evaporates, the gold nanoparticles settle in contact around the base of the spheres
Once dry, the microspheres are removed, leaving a mesh of gold nanowire
particles were added to human cell cultures, they entered 99 per cent of the cells within 6 hours. “These particles go in better than anything else,” says Mirkin, although the mechanism of absorption is unclear. The researchers then tested how well the gold-borne siRNAs did their job. They added siRNA-laden particles to cells carrying a loop of DNA bearing the gene for luciferase, the enzyme that gives fireflies their glow. A control
Society, DOI: 10.1021/ja808719p). “We can increase the lifetime of siRNA from minutes to hours – and sometimes even days,” says Mirkin. He reckons that as RNA is a salt, its high density on the particles’ surfaces creates an environment that inhibits the enzymes that break down RNA. John Rossi, an siRNA specialist at the City of Hope hospital in Duarte, California, is impressed that Mirkin’s team could deliver large amounts of siRNA to their cultured cells without obvious toxicity. Other delivery systems, such as lipids, tend to be toxic to cells at high doses, he notes. The next test will be to find out whether the particles perform as well in a living body as in the culture dish. “It’s early days, and there are a lot of delivery vehicles that work in cultured cells and haven’t worked in animals,” cautions Mark Kay, a gene therapist at Stanford University. Peter Aldhous ■
Anil Ananthaswamy ■
How to make a nanonet
Latex microspheres are placed on a glass slide and immersed in a suspension of gold nanoparticles
…while gold nanoparticles linger in cells, blocking genes GOLD nanoparticles could be an ideal way of delivering one of the hottest prospects in molecular medicine. The nanoparticles have successfully carried RNA molecules into human cells, where researchers hope they can be used to tackle everything from HIV to cancer. Over the past few years, stretches of “short interfering” RNA, or siRNA, which are just over 20 bases long, have emerged as a powerful tool in biology because they are able to “turn off” target genes. They do this by selectively interfering with the messenger RNA that is the intermediate step between a gene and the protein it codes for. This means that siRNAs could
with closely packed latex microspheres, each about 50 to 100 micrometres in diameter. By adding suitable surfactants and lowering the temperature to 4 °C, the team was able to control the evaporation and convection rates, causing the gold particles to move to the base of the latex balls where they settled to form rings and bridges. Once the liquid had evaporated, they were left with a network of connected gold nanoparticles (Physical Review Letters, vol 102, p 058303). “Our gold network is finer than spider’s silk and is also conductive,” says Vakarelski. He reckons that gold nanonets
also act as exquisitely targeted drugs, shutting down key genes from HIV and other viruses, or disabling the human genes linked with conditions from age-related sight loss to cancer. Getting large quantities of siRNA into human cells and protecting it from being broken down too quickly once inside is a tough challenge, however. Now a team led by Chad Mirkin of Northwestern University in Evanston, Illinois, has used gold nanoparticles to carry siRNA into cultures of human cells. The team’s delivery system consists of balls of gold just 13 nanometres across, each bearing about 30 short stretches of RNA bound to the gold by a connecting molecule. When these
“siRNAs could act as exquisitely targeted drugs, shutting down genes from HIV and other viruses” group of cells was given the siRNA alone. Four days later, the reduction in the activity level of the gene in the gold-dosed cells was more than double the drop found in the control cells (Journal of the American Chemical
Affordable drugs for all The patent system that has served drug companies so well may at last be changing to also help those who need drugs most, says Debora MacKenzie IT IS not a good idea to be sick in a poor country. A drug for what ails you may well not exist – unless the same illness is common in rich countries too – and even if it does exist, it is likely to be way beyond your means. Yet it is in poor countries that most of the world’s sick people live. This is the way things have been for years, partly because of a patent system that was supposed to encourage development of new pharmaceuticals. Against this background, the announcement this month by Andrew Witty, CEO of GlaxoSmithKline, the world’s second biggest pharmaceuticals firm, that GSK would free up access to patents relating to neglected diseases and cut the price of medicines for the poorest countries by at least 75 per cent has been heralded as a new dawn. GSK wants other companies to help it create a pool of patented substances and processes which anyone can use – on payment of a royalty – to develop treatments for neglected tropical diseases. “It is right that we explore new ways of stimulating research that otherwise might not happen,” Witty says. Is big pharma finally showing its caring side? Well, yes and no. Though the gesture is not quite as selfless as it seems, examination of the complexities that underlie Witty’s statement suggest that the new dawn might be real. Under the existing patent system, a company gets a 20-year monopoly on drugs that it has developed, during which it can charge high prices to cover the costs of the R&D and make a profit. 22 | NewScientist | 28 February 2009
This rather discourages companies figuring it was better to sell from investing in drugs that only them cheaply than not at all. But poor people need, since they are what actually happened was that unlikely to be able to pay enough other companies, mainly in to cover the companies’ costs. So India, started to sell their own companies will spend millions on generic versions. They were able a cure for impotence that men in to massively undercut even the rich countries will pay billions for, drug companies’ discounts. but won’t bother with a disease Now, as world trade agreements like malaria that kills one poverty- take effect in countries like India, stricken child every 30 seconds. this source of cheap versions Where drugs do exist that would of patented drugs is drying up. help people in poor countries, such Patent-holders warn that if they as the newer anti-HIV treatments, have to compete with makers of they are mostly too expensive generics, who do not have to invest while still under patent. In the 1990s, pharmaceutical companies “Patented processes would be available to researchers tried to tackle this problem by developing treatments for offering their patented drugs to African countries at big discounts, diseases of the poor”
in R&D, they will not be able to pay for research into new medicines. While there is some validity to this argument, research-based companies would in practice not be selling many patented products in the poor countries that buy generics, so their loss is small. What they really seem to be defending is the principle of stringent worldwide enforcement of patents – what is tellingly coming to be known as “old patenting”. Though no one disputes that companies need to reap rewards for the drugs they develop, there are signs that the old system is having to change. Governments are starting to take seriously the idea that rewards for R&D should be “de-linked” from the price of the product. Last May, the World Health Organization’s member states approved a plan to “explore a range of incentive schemes, including the de-linkage of the costs of R&D and the price of health products”. These might involve, for example, prizes for innovation, funded by governments or other donors. In July UNITAID, a club of countries formed in 2006 to buy drugs for the poor, proposed a patent pool that would allow drug companies to make patented drugs available to poor countries at low prices while still selling them at high prices elsewhere. And this year, the US Food and Drug Administration will start awarding “priority review vouchers” (PRVs) – fast-track licensing in the US – to any company that invents a drug for one of 16 neglected diseases. This is a “prize” worth having: PRVs
To comment on these stories go to www.NewScientist.com/section/opinion
allow a company to market a lucrative new drug a year earlier than under normal FDA review. The vouchers can also be sold, for upwards of $300 million. Where does GSK’s offer fit into all this? It too wants a patent pool along the lines of the UNITAID scheme – though not of existing drugs but of experimental molecules and processes that drug companies have patented but are not necessarily using. These molecules and processes would be available for a royalty to researchers wanting to develop new treatments for the FDA’s 16 neglected diseases. The patent holder would retain the rights to the $300 million “prize” for every drug that emerged, yet it would not itself put up the money for the R&D involved, so the offer is not quite as generous as it may seem. It should bring real benefits just the same. As Witty says, it should encourage research that otherwise would not happen – though it is worth pointing out that such a move might not have been possible had the Gates Foundation and other philanthropic groups not been pouring money into neglected diseases, thereby creating a research community ready to take up such opportunities. Pharmaceutical companies know something has to give. President Barack Obama has called for “humanitarian licensing policies that ensure medications developed with US taxpayer dollars are available off-patent in developing countries”. He has the legal right to “march in” on any patented drug developed partly with US research money, and license it to others if the patent holder is not making fair use of it. The companies will resist that. But it seems they are beginning to accept that the patent system has to change so that it can do what it was always supposed to: promote lifesaving drugs for all. ■ Debora MacKenzie is a New Scientist correspondent based in Brussels
Guest columnist Amanda Gefter
Hidden religious agendas and how to spot them AS A book reviews editor at New Scientist, I often come across so-called science books which after a few pages reveal themselves to be harbouring ulterior motives. I have learned to recognise clues that the author is pushing a religious agenda. As creationists in the US continue to lose court battles over attempts to have intelligent design taught as science in federally funded schools, their strategy has been forced to… well, evolve. That means ensuring that references to pseudoscientific concepts like ID are more heavily veiled. So I thought I’d share a few tips for spotting what may be religion in science’s clothing. Red flag number one: the term “scientific materialism”. “Materialism” is most often used in contrast to something else – something nonmaterial, or supernatural. Proponents of ID frequently lament the scientific claim that humans are the product of purely material forces. At the same time, they never define how non-material forces might work. I have yet to find a definition that characterises non-materialism by what it is, rather than by what it is not. The invocation of Cartesian dualism – where the brain and mind are viewed as two distinct entities, one material and the other immaterial – is also a red flag. And if an author describes the mind, or any biological system for that matter, as “irreducibly complex”, let the alarm bells ring. Misguided interpretations of quantum physics are a classic hallmark of pseudoscience, usually of the New Age variety, but some religious groups are now appealing to aspects of quantum weirdness to account for free will. Beware: this is nonsense. When you come across the terms “Darwinism” or “Darwinists”, take heed. True scientists rarely use these terms, and instead opt for “evolution” and “biologists”, respectively. When evolution is described as a “blind, random, undirected process”, be warned. While genetic mutations may be random, natural selection is not. When cells are
described as “astonishingly complex molecular machines”, it is generally by breathless supporters of ID who take the metaphor literally and assume that such a “machine” requires an “engineer”. If an author wishes for “academic freedom”, it is usually ID code for “the acceptance of creationism”. Some general sentiments are also red flags. Authors with religious motives make shameless appeals to common sense, from the staid – “There is nothing we can be more certain of than the reality of our sense of self” (James Le Fanu in Why Us?) – to the silly – “Yer granny was an ape!” (creationist blogger Denyse O’Leary). If common sense were a reliable guide, we wouldn’t need science in the first place. Religiously motivated authors also have a bad habit of linking the cultural implications of a theory to the truth-value of that theory. The ID crowd, for instance, loves to draw a line from
“If an author wishes for ‘academic freedom’, it is usually code for ‘the acceptance of creationism’ ” Darwin to the Holocaust, as they did in the “documentary” film Expelled: No intelligence allowed. Even if such an absurd link were justified, it would have zero relevance to the question of whether or not the theory of evolution is correct. Similarly, when Le Fanu writes that Darwin’s On the Origin of Species “articulated the desire of many scientists for an exclusively materialist explanation of natural history that would liberate it from the sticky fingers of the theological inference that the beauty and wonder of the natural world was direct evidence for ‘A Designer’ ”, his statement has no bearing on the scientific merits of evolution. It is crucial to the public’s intellectual health to know when science really is science. Those with a religious agenda will continue to disguise their true views in their effort to win supporters, so please read between the lines. ■
Amanda Gefter is an editor for the Opinion section of New Scientist
28 February 2009 | NewScientist | 23
OPINION LETTERS Double-cross helix? From Denise Syndercombe Court, Barts and The London School of Medicine and Dentistry Your editorial and articles on DNA testing raise the important issue of obtaining appropriate consent for an individual’s DNA to be tested (31 January, p 3 and p 6; 24 January, p 8). The law in the UK is clear on this: it is illegal for a laboratory to test an individual’s DNA without proper informed consent. Even if companies refuse to test items such as discarded chewing gum and tissues, there is still a danger of tests being conducted without proper consent. A laboratory receiving “consent forms” by post with samples cannot establish that informed consent has been freely given. Only consent given in front of, and verified by, an independent person of appropriate standing, such as a registered medical professional, can offer assurance that the law is being complied with and so protect an individual against their DNA being “stolen”.
Also of significant concern are questions about the scientific competence and experience of particular laboratories to provide the correct information and interpret it appropriately. Processing DNA and getting a result is frighteningly easy, but obtaining the correct result and interpreting it reliably is complicated. Those who make claims which go beyond their expertise may be defrauding members of the public, with serious consequences. London, UK From John Baker You hail the UK legislation banning covert DNA testing. Yet the UK already leads the world in illegal DNA testing – the police are holding 857,366 DNA samples of people illegally, as recently determined by the European Court of Human Rights, in a unanimous and damning judgement (13 December 2008, p 7). The UK holds 4.5 million DNA samples, which probably cover most of the population through familial matching. I am far more
Enigma Number 1534
Head start SUSAN DENHAM Harey and Tortus decided to race from Harey’s house to school, a distance of a whole number of metres. They each ran at their own steady speed and when Harey reached school, Tortus was over half way there, but still had a twofigure number of metres to go. The next day they repeated the race, but this time Harey decided to
give Tortus a head start equal to the winning margin of the previous day. So Harey walked that number of metres away from his house in the opposite direction to school before the race started. Once again, Harey got to school first, ahead by a twofigure number of metres. The second winning margin had the same pair of digits as the first, but in reverse order. How far is it from Harey’s house to the school?
WIN £15 will be awarded to the sender of the first correct answer opened on Tuesday 31 March. The Editor’s decision is final. Please send entries to Enigma 1534, New Scientist, Lacon House, 84 Theobald’s Road, London WC1X 8NS, or to firstname.lastname@example.org (please include your postal address). Answer to 1528 Ad hoctagon: The area of the octagon is 140 cm2 The winner Ian Chantrell of Plymouth, UK
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threatened by this database and the possibilities, such as criminals planting my DNA at a crime scene, than I am by individuals covertly processing my DNA. In the case of paternity, historically only the mother has been sure, excluding maternity ward mix-ups. The father has a
the right to find out the truth. Should this give them the right to delve into the double helices of anyone who they think can help answer their questions, including innocent parties, without consent? The UK parliament has decided that everyone’s genetic privacy must be respected. Drafting a law that selectively strips rights of privacy from individuals who breach codes of sexual conduct may be impractical.
small chance of having been cuckolded. Why should he be denied this information? Regardless, there is no realistic way of keeping people in ignorance, even if it were justifiable. I recommend routine verification of paternity at birth, with immediate destruction of the samples. Chalfont St. Giles, Buckinghamshire, UK From Tony Park You raise concerns about the damage that covert genetic testing could do to families, yet simply asking for consent for a paternity test could damage the relationship, regardless of the result. In cases where the test shows infidelity or unexpected paternity, it is difficult to argue that the test is the cause of any relationship problems that may result. Similarly, the argument that great harm could result from finding out that your mother had been lying to you all your life is false. The harm is in the lying, not the finding out. Dunlop, Ayrshire, UK The editor writes: ■ People who suspect sexual betrayal feel strongly they have
From Antony Naylor In the concept proposed by Marcus Chown in the article “All the world’s a hologram” (17 January, p 24), the twodimensional surface of the sphere surrounding the universe is the hologram and the universe (including you) is a holographic image – a point glossed over by the oversimplified wording that appeared on the cover of the issue. There are two main problems with this theory. First, if there is a projected image, then some energy must interact with the hologram, either as transmitted or reflected energy. This cannot be electromagnetic radiation as its finite velocity would raise all sorts of problems with time, including predestination. So what is it and where does it come from? Secondly, if the universe is expanding then the elements of the hologram must either be increasing in number or be being stretched. In the case of a black hole, the event horizon does increase in size as energy falls in, but there is no evidence that energy is falling into the universe. If the elements are being stretched, the graininess of the universe must be increasing. These issues can be resolved if one accepts that while the elements in the universe and those on the surface of the sphere can be mapped or transformed onto each other, neither the
For more letters visit www.NewScientist.com/topic/letters ■ Double-cross helix? ■ Truth or pare ■ Thou shalt not be popular ■ Day after day ■ Cosmic numerology ■ Science play time
elements inside nor those on the surface create each other. This concept still leaves the universe with graininess at a scale of around 10-16 metres – compared with the Planck length of 10-35 metres on the surface – but it does raise questions about the change in graininess as the universe has expanded, assuming the Planck length has always been the same. Wasaga Beach, Ontario, Canada
Debit risk From Tim McCormack Mark Buchanan’s discussion of “unknown unknowns” (24 January, p 32) could usefully be applied to banks’ assumptions of credit risk exposure. Some use Monte Carlo simulations to calculate an acceptable level of value at risk. These use tables of probability of loans defaulting, provided by the rating agencies. One problem with this method is that the probability of any event occurring during the Monte Carlo simulation depends on the number of iterations of the simulation performed. In 1000 iterations there may be a 10 per cent chance of an “AAA”rated bond failure being included in the results. If by chance an AAA failure shows up in such a simulation run, it will produce a spike in the tail of the results graph and is likely to be dismissed as an improbable event. Why, then, include the possibility of an AAA default in the first place? Foyers, Invernessshire, UK
Magnetic cattle From Michael Kellock You reported on research, based on a large number of satellite photos, showing that cattle and some wild grazing animals align themselves predominantly along north-south lines, suggesting an awareness of the Earth’s magnetic field (30 August 2008, p 10). I have
since paid particular attention to the hundred or so cattle and sheep visible from my kitchen window. Overwhelmingly, these animals align east-west. Frequently, this appears to be a response to strong winds, driving rain or fierce sun. Even in tranquil times, there is a clear east-west preference. It seems animals in Australia march to a different drum. Grazing kangaroos show no alignment preference at all. Foster, Victoria, Australia
28 units, sharply reducing the amount of time left to complete the primary task. For n people, this overhead is equivalent to (n × (n-1))/2 which is the number of unique pairs that can be chosen from the people communicating with each other. Try it. I would recommend reading Parkinson’s Law: Or the pursuit of progress. It’s must for scientists, engineers and managers. Stoke Gabriel, Devon, UK
Talk isn’t cheap From Ted Lovesey Mark Buchanan refers to humourist C. Northcote Parkinson’s ideas about committees (10 January, p 38). Parkinson’s suggestions have more far-reaching applications than just committee size. When working on a project to reduce the crew workload in a large anti-submarine aircraft, I was continually being pressured to increase the crew size. In fact, such an increase would have added to the problem. This is because there is a “communications overhead” created by people interacting with each other. Say there were 1 unit of communication overhead for two people. With three people, the overhead for all three communicating together increases to 3 units – one for each two-way conversation available. By the time eight crew members are communicating, the overload has risen exponentially to
From James Sandemans I enjoyed Paul Collins’s article on metal balloons down the ages (10 January, p 44). I am not sure, however, about his remark that, since 1941, “no more metal-clads have taken to the skies”. I seem to recall reading, 30 or 40 years ago, of a successful project at the Massachusetts Institute of Technology to design, build and fly a balloon constructed entirely of lead. Glasgow, UK The editor writes: ■ MIT’s neighbours at the consultancy Arthur D. Little flew both a lead balloon and a dirigible in May 1977: see photos at www. leadballoon.notlong.com. The US TV programme Mythbusters also managed to loft a balloon made of lead foil in January 2008.
Holy herd From Zoe Hudson David Robson discussed the herd mentality in humans (7 February, p 13). On the rare occasions that I have been to church, I witnessed the power of singing as part of a congregation and the connection you feel with those standing next to you. I found myself caught up in the moment with emotions of unity, purpose, elatedness and (unusually for me) spirituality.
From such experiences I can appreciate how contagious the belief in a god could be, especially when one is feeling particularly lost in life. Reinforcing faith through mass worship is evident in religious holidays, pilgrimages and ritualistic behaviour. I believe the herd mentality is fundamental to the persistence of organised religion. Oxford, UK
For the record ■ We wrongly stated that the World Health Organization recommended in September 2008 that the electronic cigarette be banned (14 February, p 33). The WHO in fact stated that it did not consider the electronic cigarette to be a legitimate therapy for smokers trying to quit. ■ We said that in 1709 “from Czechoslovakia in the east… everything turned to ice” (7 February, p 46). No such country existed in 1709. It was founded in 1918 and split into the Czech Republic and Slovakia in 1993. ■ Our picture of the starfish Luidia sarsi was upside down (24 January, p 36).
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28 February 2009 | NewScientist | 25
OPINION INTERVIEW Photography: Michael Struik
Universe on her shoulders Next month Fabiola Gianotti takes over as head of ATLAS at the Large Hadron Collider at CERN in Switzerland. The largest experiment of its kind, it could answer some of the mysteries of the universe. She talks to Anil Ananthaswamy about dark matter and deep truths
What are your thoughts on becoming the first woman to head a particle physics experiment at the LHC?
CERN is such a rich environment: there are people from all over the world, young students work with established scientists and Nobel prizewinners. So geographical origin, age and gender make no difference here. I don’t feel there is anything special about a woman leading a big scientific project. On the other hand, I hope that as a woman scientist who has achieved a level of visibility in a big experiment like ATLAS, I can be an encouragement to young women who are thinking of a scientific career. Why did you decide to become a particle physicist?
I came to physics from very far away. When I was a young girl, I loved art and music. I had been studying piano quite seriously at a conservatory and had taken courses in high school targeted towards literature, languages like ancient Greek and Latin, philosophy and history of art. I loved these subjects but I was
PROFILE Fabiola Gianotti has a PhD in experimental sub-nuclear physics from the University of Milan, Italy. She joined CERN in 1987, working on various experiments including UA2 and ALEPH on the Large Electron Positron collider, the precursor to the LHC at CERN. Gianotti is a member of the Physics Advisory Committee at Fermilab, the particle physics laboratory at Batavia, Illinois. A trained pianist, she has a professional music diploma from the Milan Conservatory.
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also a very curious little girl. I was fascinated by the big questions. Why are things the way they are? This possibility of answering fundamental questions has always attracted me – my mind, my spirit, everything. So, when I had to choose what I wanted to do with my life, I thought that physics could answer these big questions in a more concrete way than philosophy. I was right – in that I’m very happy now. Give us a sense of the size and scope of ATLAS.
The ATLAS collaboration consists of almost 3000 physicists from 169 institutions, 37 countries and five continents. ATLAS is the biggest detector ever built at a particle collider and its spectacular size strikes people immediately when they visit the underground cavern it is housed in – it’s as big as a five storey building. This size is combined with an enormous complexity. There are 100 million independent electronic signals that we need to record in order to reconstruct the hundreds of particles produced in every proton-proton collision. The trajectories of the particles must be reconstructed with micrometre precision. This amazing combination of size, complexity and precision has made the technology very challenging. ATLAS and indeed the other detectors at the LHC are instruments without precedent.
itself, physics beyond the so-called standard model [which explains all known particles and the forces that act upon them]. We expect to find answers to some fundamental questions and mysteries, many of which have been with us for decades. For instance, what is the origin of mass? It’s a question related to the existence of the Higgs boson. Are there other forces of nature, in addition to the four forces we already know of? Are there additional dimensions of space? What is the composition of the universe’s dark matter?
What are the key goals of ATLAS?
ATLAS will sift through particles created by extremely high-energy proton-proton collisions. We are starting on a fantastic scientific journey. We believe that at this energy scale, new physics should manifest
What would you personally like to see ATLAS discover first?
Dark matter. I would be very, very happy if we discover the particle that explains 20 per cent of the universe’s composition. Accelerators like
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instruments which are at the cutting edge of technology in various sectors, from electronics to cryogenics, and which have spin-off benefits to society. Thirdly, these projects have been carried out in an international environment, with physicists, engineers and technicians from all over the world, bringing nations together through science and breaking political barriers. In our project, we have people from countries that are historically not the best of friends. What’s the mood at CERN, given that the start of the LHC got delayed?
The inauguration of the LHC on 10 September was a big success, there was a lot of excitement. And then 19 September, when the accident happened, was like a cold shower. There was of course big disappointment, especially among the younger people, who
“ We have to find something, and nature could well present us with surprises” were so excited and so happy during the first few days when the LHC was circulating single beams. On the other hand, this is a very difficult project technologically. It was started almost 20 years ago and will last for another 20 years, and such hiccups have to be taken into account. We are on a path which otherwise has been very successful until now, and will be very successful. We just have to be a little bit more patient. The LHC and ATLAS could potentially reveal some deep truths about how the universe works. What do you feel when you think about it?
the LHC allow us to study the infinitely small – the basic constituents of matter – and this can tell us about the structure and evolution of the universe, stressing the link between the infinitely small and the infinitely big. Have you thought about what would happen if no new physics is discovered at the LHC?
It is a good question, but it’s difficult to answer. Based on what we have learned from experimental and theoretical work over the last few decades, there must be something new at the energy scales that the LHC will offer. Perhaps there will be just one Higgs boson, or a new mechanism playing the same role, but we expect more. We know that the standard model is not a complete theory of elementary particles, because it cannot
answer all our questions. We expect it to start to break down at the energy scale of the LHC. There must be new physics there. Perhaps they won’t be the answers that we have in mind, but there must be answers. Nature could well present us with surprises and this will be one of the most exciting possibilities. After all, research is about looking for something that we don’t know a priori. What has it been like working on ATLAS?
Building the LHC and experiments like ATLAS is an unprecedented scientific, technological and human adventure. What makes my life as a scientist at CERN so special is the combination of three elements. One is the exciting physics goals. Then, to address these questions, we had to develop high-tech
Feelings of excitement, of course, and the awareness of being close to something very important and great for humankind. Fundamental research is a duty and a need of human beings. The 13th century Italian poet Dante said that we were not created to live as animals but to pursue virtue and knowledge. As human beings, the pursuit of fundamental research and knowledge is a need for us, which separates us from animals or vegetables. It is like the need for art. Research bring knowledge, and knowledge brings progress, always. If we discover something fundamental at the LHC, it will be a bit like going to the heart of the universe. When you are getting closer to the fundamentals, to the basic questions of where the universe comes from and where it is going, there’s a very special feeling. ■ 28 February 2009 | NewScientist | 27
28 | NewScientist | 28 February 2009
Surviving in a warmer world If the planet warms by 4 ºC – as it might this century – it will change beyond all recognition. A radical new world order may be our only hope, says Gaia Vince
The cities that escape the floods may still be consumed by desert
LLIGATORS basking off the English coast; a vast Brazilian desert; the mythical lost cities of Saigon, New Orleans, Venice and Mumbai; and 90 per cent of humanity vanished. Welcome to the world warmed by 4 °C. Clearly this is a vision of the future that no one wants, but it might happen. Fearing that the best efforts to curb greenhouse gas emissions may fail, or that planetary climate feedback mechanisms will accelerate warming, some scientists and economists are considering not only what this world of the future might be like, but how it could sustain a growing human population. They argue that surviving in the kinds of numbers that exist today, or even more, will be possible, but only if we use our uniquely human ingenuity to cooperate as a species to radically reorganise our world. The good news is that the survival of humankind itself is not at stake: the species could continue if only a couple of hundred individuals remained. But maintaining the current global population of nearly 7 billion, or more, is going to require serious planning. Four degrees may not sound like much – after all, it is less than a typical temperature change between night and day. It might sound quite pleasant, like moving to Florida from Boston, say, or retiring from the UK to southern Spain. An average warming of the entire globe by 4 °C is a very different matter, however, and would render the planet unrecognisable from anything humans have ever experienced. Indeed, human activity has and will have such a great impact that some have proposed describing the time from the 18th century onward as a new geological era, marked by human activity. “It can be considered the Anthropocene,” says Nobel
prizewinning atmospheric chemist Paul Crutzen of the Max Planck Institute for Chemistry in Mainz, Germany. A 4 °C rise could easily occur. The 2007 report of the Intergovernmental Panel on Climate Change, whose conclusions are generally accepted as conservative, predicted a rise of anywhere between 2 °C and 6.4 °C this century. And in August 2008, Bob Watson, former chair of the IPCC, warned that the world should work on mitigation and adaptation strategies to “prepare for 4 °C of warming”. A key factor in how well we deal with a warmer world is how much time we have to adapt. When, and if, we get this hot depends not only on how much greenhouse gas we pump into the atmosphere and how quickly, but how sensitive the world’s climate is to these gases. It also depends whether “tipping points” are reached, in which climate feedback mechanisms rapidly speed warming. According to models, we could cook the planet by 4 °C by 2100. Some scientists fear that we may get there as soon as 2050. If this happens, the ramifications for life on Earth are so terrifying that many scientists contacted for this article preferred not to contemplate them, saying only that we should concentrate on reducing emissions to a level where such a rise is known only in nightmares. “Climatologists tend to fall into two camps: there are the cautious ones who say we need to cut emissions and won’t even think about high global temperatures; and there are the ones who tell us to run for the hills because we’re all doomed,” says Peter Cox, who studies the dynamics of climate systems at the University of Exeter, UK. “I prefer a middle ground. We have to accept that changes are inevitable and start to adapt now.” > 28 February 2009 | NewScientist | 29
Bearing in mind that a generation alive today might experience the scary side of these climate predictions, let us head bravely into this hotter world and consider whether and how we could survive it with most of our population intact. What might this future hold? The last time the world experienced temperature rises of this magnitude was 55 million years ago, after the so-called Palaeocene-Eocene Thermal Maximum event. Then, the culprits were clathrates – large areas of frozen, chemically caged methane – which were released from the deep ocean in explosive belches that filled the atmosphere with around 5 gigatonnes of carbon. The already warm planet rocketed by 5 or 6 °C, tropical forests
water will evaporate faster, leaving drought across Asia. Bangladesh stands to lose a third of its land area – including its main bread basket. The African monsoon, although less well understood, is expected to become more intense, possibly leading to a greening of the semi-arid Sahel region, which stretches across the continent south of the Sahara desert. Other models, however, predict a worsening of drought all over Africa. A lack of fresh water will be felt elsewhere in the world, too, with warmer temperatures reducing soil moisture across China, the south-west US, Central America, most of South America and Australia. All of the world’s major deserts are predicted to expand, with the Sahara
”Humans will survive as a species, but the cull this century will be huge” sprang up in ice-free polar regions, and the oceans turned so acidic from dissolved carbon dioxide that there was a vast die-off of sea life. Sea levels rose to 100 metres higher than today’s and desert stretched from southern Africa into Europe. While the exact changes would depend on how quickly the temperature rose and how much polar ice melted, we can expect similar scenarios to unfold this time around. The first problem would be that many of the places where people live and grow food would no longer be suitable for either. Rising sea levels – from thermal expansion of the oceans, melting glaciers and storm surges – would drown today’s coastal regions in up to 2 metres of water initially, and possibly much more if the Greenland ice sheet and parts of Antarctica were to melt. “It’s hard to see west Antarctica’s ice sheets surviving the century, meaning a sea-level rise of at least 1 or 2 metres,” says climatologist James Hansen, who heads NASA’s Goddard Institute for Space Studies in New York. “CO2 concentrations of 550 parts per million [compared with about 385 ppm now] would be disastrous,” he adds, “certainly leading to an ice-free planet, with sea level about 80 metres higher… and the trip getting there would be horrendous.” Half of the world’s surface lies in the tropics, between 30° and -30° latitude, and these areas are particularly vulnerable to climate change. India, Bangladesh and Pakistan, for example, will feel the force of a shorter but fiercer Asian monsoon, which will probably cause even more devastating floods than the area suffers now. Yet because the land will be hotter, this 30 | NewScientist | 28 February 2009
reaching right into central Europe. Glacial retreat will dry Europe’s rivers from the Danube to the Rhine, with similar effects in mountainous regions including the Peruvian Andes, and the Himalayan and Karakoram ranges, which as result will no longer supply water to Afghanistan, Pakistan, China, Bhutan, India and Vietnam. Along with the exhaustion of aquifers, all this will lead to two latitudinal dry belts where human habitation will be impossible, say Syukuro Manabe of Tokyo University, Japan, and his colleagues. One will stretch across Central America, southern Europe and north Africa, south Asia and Japan; while the other will cover Madagascar, southern Africa, the Pacific Islands, and most of Australia and Chile (Climatic Change, vol 64, p 59).
The world: 4°C warmer No one knows exactly what this world will look like, but models provide insights into forced human migrations and our future power generation
Arctic passage With no sea ice, this valuable shipping route is open all year, providing transportation links beween habitable zones in Canada and Russia
Reliable precipitation and warmer temperatures provide ideal growing conditions for most of the world's subsistence crops
Desertification led to the last inhabitants of this region migrating north. The Colorado river is a mere trickle. The land is used for solar farming and geothermal energy
Deglaciation means this area is dry and uninhabitable
The high life The only places we will be guaranteed enough water will be in the high latitudes. “Everything in that region will be growing like mad. That’s where all the life will be,” says former NASA scientist James Lovelock, who developed the “Gaia” theory, which describes the Earth as a self-regulating entity. “The rest of the world will be largely desert with a few oases.” So if only a fraction of the planet will be habitable, how will our vast population survive? Some, like Lovelock, are less than optimistic. “Humans are in a pretty difficult position and I don’t think they are clever enough to handle what’s ahead. I think they’ll survive as a species all right, but the cull during this century is going to be huge,” he >
Western Antarctica Unrecognisable now. Densely populated with high-rise cities
Food-growing zones / Compact high-rise cities
Greenlandâ€™s ice sheet will be melting rapidly
Compact high-rise cities would provide shelter for much of the world's population
Reliable precipitation and warmer temperatures provide ideal growing conditions for most of the world's subsistence crops
Deserts have encroached on the continent, rivers have dried up and the Alps are snow-free. Goats and other hardy animals are kept at the fringes
North Africa/Middle East/ Southern US Solar Energy Belt stretches for thousands of kilometres, employing a mixture of photovoltaic and solar thermal energy. At frequent intervals a high voltage direct-current substation sends power north
Dried rivers and aquifers mean this region has been abandoned. Intense monsoons have helped erode the land, leaving a dustbowl
Mostly desert, though some models show greening of the Sahel
Most of the Himalayan glaciers have melted, with repercussions for many of the major rivers in the region. Bangladesh is largely abandoned, as is south India, Pakistan and Afghanistan. Isolated communities remain in pockets
Vanished beneath the sea
Melted glaciers revealed a new arable zone, although the poor soils needed preparation
Uninhabitable due to floods, drought or extreme weather
In the far north and Tasmania, compact cities house people and crops are grown. The rest of the continent is given to solar energy production and uranium mining for nuclear power
Potential for reforestation
Land lost due to rising sea levels, assuming a 2-metre rise
Unrecognisable. This densely populated island state has high-rise cities and intensive farming
28 February 2009 | NewScientist | 31
says. “The number remaining at the end of the century will probably be a billion or less.” John Schellnhuber of the Potsdam Institute for Climate Impacts Research in Germany is more hopeful. The 4 °C warmer world would be a huge challenge, he says, but one we could rise to. “Would we be able to live within our resources, in this world? I think it could work with a new division of land and production.” In order to survive, humans may need to do something radical: rethink our society not along geopolitical lines but in terms of resource distribution. “We are locked into a mindset that each country has to be selfsustaining in food, water and energy,” Cox says. “We need to look at the world afresh and see it in terms of where the resources are, and then plan the population, food and energy production around that. If aliens came to Earth they’d think it was crazy that some of the driest parts of the world, such as Pakistan and Egypt, grow some of the thirstiest crops for export, like rice.” Taking politics out of the equation may seem unrealistic: conflict over resources will likely increase significantly as the climate changes, and political leaders are not going to give up their power just like that. Nevertheless, overcoming political hurdles may be our only chance. “It’s too late for us,” says President Anote Tong of Kiribati, a submerging island state in Micronesia, which has a programme of gradual migration to Australia and New Zealand. “We need to do something
” We will need to abandon huge areas and move people to where the water is” drastic to remove national boundaries.” Cox agrees: “If it turns out that the only thing preventing our survival was national barriers then we would need to address this – our survival is too important,” he says. Imagine, for the purposes of this thought experiment, that we have 9 billion people to save – 2 billion more than live on the planet today. A wholescale relocation of the world’s population according to the geography of resources means abandoning huge tracts of the globe and moving people to where the water is. Most climate models agree that the far north and south of the planet will see an increase in precipitation. In the northern hemisphere this includes Canada, Siberia, Scandinavia and newly ice-free parts of Greenland; in the southern hemisphere, Patagonia, Tasmania and the far north of Australia, New Zealand and perhaps newly ice-free parts of the western Antarctic coast. If we allow 20 square metres of space per person – more than double the minimum habitable space allowed per person under English planning regulations – 9 million people would need 18,000 square kilometres of land to live on. The area of Canada alone is 9.1 million square kilometres and, combined
with all the other high-latitude areas, such as Alaska, Britain, Russia and Scandinavia, there should be plenty of room for everyone, even with the effects of sea-level rise. These precious lands with access to water would be valuable food-growing areas, as well as the last oases for many species, so people would be need to be housed in compact, highrise cities. Living this closely together will bring problems of its own. Disease could easily spread through the crowded population so early warning systems will be needed to monitor any outbreaks. It may also get very hot. Cities can produce 2 °C of additional localised warming because of energy use and things like poor reflectivity of buildings and lower rates of evaporation from concrete surfaces, says Mark McCarthy, an urban climate modeller at the UK Met Office’s Hadley Centre. “The roofs could be painted a light, reflective colour and planted with vegetation,” McCarthy suggests. Since water will be scarce, food production will need to be far more efficient. Hot growing seasons will be more common, meaning that livestock will become increasingly stressed, and crop growing seasons will shorten, according to David Battisti of the University of Washington in Seattle and his colleagues (Science, vol 323, p 240). We will need heat and drought-tolerant crop varieties, they suggest. Rice may have to give way to less thirsty staples such as potatoes.
GIDEON MENDEL FOR ACTION AID/CORBIS
With fiercer and shorter monsoons, droughts will quickly follow floods 32 | NewScientist | 28 February 2009
This will probably be a mostly vegetarian world: the warming, acidic seas will be largely devoid of fish, thanks to a crash in plankton that use calcium carbonate to build shells. Molluscs, also unable to grow their carbonate shells, will become extinct. Poultry may be viable on the edges of farmland but there will simply be no room to graze cattle. Livestock may be restricted to hardy animals such as goats, which can survive on desert scrub. One consequence of the lack of cattle will be a need for alternative fertilisers – processed human waste is a possibility. Synthetic meats and other foods could meet some of the demand. Cultivation of algal mats, and crops grown on floating platforms and in marshland could also contribute.
GEORGE STEINMETZ/CORBIS ABIR ABDULLAH/EPA/CORBIS
As desert encroaches on fertile land, as it has near Dunhuang, China, people will be forced polewards
Supplying energy to our cities will also require some adventurous thinking. Much of it could be covered by a giant solar belt, a vast array of solar collectors that would run across north Africa, the Middle East and the southern US. Last December, David Wheeler and Kevin Ummel of the Center for Global Development in Washington DC calculated that a 110,000-square-kilometre area of solar panels across Jordan, Libya and Morocco would be “sufficient to meet 50 to 70 per cent of worldwide electricity production, or about three times [today’s] power consumption in Europe”. High-voltage direct current transmission lines could relay this power to the cities, or it could be stored and transported in hydrogen – after using solar energy to split water in fuel cells. If the comparatively modest level of solar installation that Wheeler and Ummel propose were to begin in 2010, the total power delivery by 2020 could be 55 terawatt hours per year – enough to meet the household electricity
demand of 35 million people. This is clearly not enough to provide power for our future 9 billion, but improving efficiency would reduce energy consumption. And a global solar belt would be far larger than the one Wheeler and Ummel visualise. Nuclear, wind and hydropower could supplement output, with additional power from geothermal and offshore wind sources. Each high-rise community housing block could also have its own combined heat and power generator, running on sustainable sources, to supply most household energy. If we use land, energy, food and water efficiently, our population has a chance of surviving – provided we have the time and willingness to adapt. “I’m optimistic that we can reduce catastrophic loss of life and reduce the most severe impacts,” says Peter Falloon, a climate impacts specialist at the Hadley Centre. “I think there’s enough knowledge now, and if it’s used sensibly we could adapt to the climate change that we’re already
committed to for the next 30 or 40 years.” This really would be survival, though, in a world that few would choose to live. Large chunks of Earth’s biodiversity would vanish because species won’t be able to adapt quickly enough to higher temperatures, lack of water, loss of ecosystems, or because starving humans had eaten them. “You can forget lions and tigers: if it moves we’ll have eaten it,” says Lovelock. “People will be desperate.” Still, if we should find ourselves in such a state you can bet we’d be working our hardest to get that green and pleasant world back, and to prevent matters getting even worse. This would involve trying to limit the effects climate feedback mechanisms and restoring natural carbon sequestration by reinstating tropical forest. “Our survival would very much depend on how well we were able to draw down CO2 to 280 parts per million,” Schellnhuber says. Many scientists think replanting the forests would be impossible above a certain temperature, but it may be possible to reforest areas known as “land-atmosphere hotspots”, where even small numbers of trees can change the local climate enough to increase rainfall and allow forests to grow. Ascension Island, a remote outpost buffeted by trade winds in the mid-Atlantic, may be a blueprint for this type of bioengineering. Until people arrived in the 17th century, vegetation was limited to just 25 scrubby species. But plantings by British servicemen posted there produced a verdant cloud forest. “It shows that if you have rainfall, forest can grow within a century,” says ecologist David Wilkinson of Liverpool John Moores University in the UK, who studied the phenomenon. Even so, the most terrifying prospect of a world warmed by 4 °C is that it may be impossible to return to anything resembling today’s varied and abundant Earth. Worse still, most models agree that once there is a 4 °C rise, the juggernaut of warming will be unstoppable, and humanity’s fate more uncertain than ever. “I would like to be optimistic that we’ll survive, but I’ve got no good reason to be,” says Crutzen. “In order to be safe, we would have to reduce our carbon emissions by 70 per cent by 2015. We are currently putting in 3 per cent more each year.” ■ Gaia Vince is a freelance science writer who is travelling the world. www.wanderinggaia.com To find out what will be left to harvest from the sea in the warmer world of the future, grab a copy of next week’s New Scientist. On sale 5 March. 28 February 2009 | NewScientist | 33
Rise of the robogeeks Forget the likes of Terminator and WallÂˇE â€“ the first intelligent robot to stalk this earth could be seriously square, says Michael Brooks 34 | NewScientist | 28 February 2009
”Human brains don’t work by magic, so whatever it is they do should be doable by machine”
N December, philosopher and artificial intelligence expert Aaron Sloman announced his intention to create nothing less than a robot mathematician. He reckons he has identified a key component of how humans develop mathematical talent. If he’s right, it should be possible to program a machine to be as good as us at mathematics, and possibly better. This is no mad quest, insists Sloman, of the University of Birmingham in the UK. “Human brains don’t work by magic, so whatever it is they do should be doable in suitably designed machines,” he says. Sloman’s creature is not meant to be a mathematical genius capable of advancing the frontiers of mathematical knowledge: his
primary aim, outlined in the journal Artifical Intelligence (vol 172, p2015), is to use such a machine to improve our understanding of where our mathematical ability comes from. Nevertheless, it is possible that such a robot could take us beyond what mathematicians have achieved so far. Forget robot vacuum cleaners and android waitresses; we’re talking about a machine that could spawn a race of cyber-nerds capable of creating entirely new forms of mathematics. The field of artificial intelligence has promised much before, of course. Early researchers thought it might open a fast-track to understanding consciousness, and there were claims that artificially intelligent computers and robots would change the world. The truth has been more prosaic. AI has done some clever things, such as give us great chess players and voice recognition software, but it hasn’t delivered a revolution. But when it comes to mathematics, we can’t rule one out yet, says Alison Pease, who researches the philosophy of mathematics at the University of Edinburgh, UK. Pease teaches computers to do mathematics using AI programs, and thinks a computer really could astonish its programmer with a new mathematical insight. “Ours hasn’t yet, but there is no reason why one shouldn’t in the future,” she says. The first concrete step towards this scenario came with a program written by Simon Colton, now at Imperial College London. The program was named HR, in honour of the mathematicians Godfrey Harold Hardy and Srinivasa Ramanujan. It looked for “interesting” sequences of numbers (New Scientist, 24 February 2001, p 13). Some of HR’s discoveries have even been published – and HR, rather than Colton, got the credit. Though they might not look like cutting-edge advances, they could yet prove important. “I always refer to HR’s work in number theory as recreational mathematics, but things that look insignificant can end up being hugely significant and interesting,” Colton says. Pease and her colleagues Alan Smaille
and Markus Guhe have recently taken things further. In their Edinburgh computing laboratory they have been running virtual mathematics conferences, populated entirely by digital mathematicians (see “Reinventing the conjecture”, page 36). So where might that lead? All the way to significant new mathematics, Sloman hopes. His idea is that our key mathematical capabilities are formed in childhood. So rather than engineering a fully fledged mathematician’s brain, Sloman thinks we should build a robot with a child-like brain and let it grow into its mathematical destiny. There’s just one problem. How do we know which of our childhood capabilities equip us for a life of juggling numbers? Sloman is busy gathering clues. The answer, he reckons, lies in the spatial awareness skills that children must acquire in order to negotiate their world: skills such as knowing that a toy train pushed into a tunnel will come out the other side. Or that a jigsaw puzzle piece fits its gap only when correctly oriented. Or that the number of toys on the sofa does not depend on the order in which you count them.
From the minds of babes You might be surprised to learn, for instance, that you grasped the topological concept called “the transitivity of containment” when you were still a toddler. Stacking cups, one inside the other, you learned that the small cup would fit not only in the medium-sized cup, but also inside the big one. Transitivity of containment, like other geometrical and topological concepts, is learned through experience. “There are hundreds, if not thousands more examples of things a child learns empirically, that are later seen to be theorems in topology, geometry and arithmetic,” Sloman says. At some point, children make that jump for themselves. As toddlers, we soon translate our experiences into general theorems which we use to make predictions. Take the train-through-a-tunnel example. By repeated experiences like this, toddlers > 28 February 2009 | NewScientist | 35
learn the basic properties of rigid rods. That’s why a 3-year-old carrying a long broom handle can negotiate a narrow corridor, turn a corner at the end without getting the broom handle caught in the vertical bars of a stair-gate, then make adjustments so that the handle will go through the next doorway. “There is a switch from learning empirically to realising it has ‘simply got to be like that’,” Sloman says. And here is the key to the emergence of the mathematical mind. “The mechanisms that make that possible in a child are related to what makes it possible for them to go on to become a mathematician,” Sloman says. “A lot of abstract maths has its roots in our ability to think about space and time, processes, and interactions between processes and structures.” Sloman has gone back to basics, to watch how children learn to navigate the world around them. He is building an archive of observations of children performing pseudo-mathematical tasks. These navigational and object manipulation skills –
or at least the ability to acquire them quickly – must be encoded in the genome, Sloman reckons. And that means they could be encoded in a machine. Sloman is still a long way from designing his robot toddler. Once he has catalogued the abilities of children at various stages of development, he still has to work out how to understand the mathematical implications of those abilities, then represent them in some form of computer code. “Information needs to be encoded in some form in order to be usable,” he says. The gargantuan scale of the task means his aims are necessarily modest: at this stage he is simply trying to show a link between spatial manipulations and the basics of mathematics. Anything more would be a bonus. But just how big could that bonus be? Could a robot mathematician really do something interesting? “In principle, yes, absolutely,” Pease says. But, she adds, the story-so-far tempers her optimism. “Of all the scientific and mathematical discovery programs I’ve
Reinventing the conjecture The traditional view of mathematics sees it as a set of some eternally existing rules that describe the universe. Doing maths involves exploring this abstract, ethereal domain. Though appealing to many, this notion of mathematicians as intrepid explorers is nothing more than a romantic myth, according to Alison Pease of the University of Edinburgh, UK. “Maths is not discovery,” she says. “It’s a thing that we invent.” It is something that her computers can invent too, she insists. Pease runs an AI program called HRL, which puts together “agents” in a student-teacher relationship. The students are programmed to take some input information, make inferences from it and try to assess just how “interesting” those inferences are. If sufficiently interesting, the teacher gets involved, calling a group brainstorm designed to develop the ideas further. One of HRL’s early successes was the independent invention of a mathematical proposition called Goldbach’s conjecture. One of the students was given the concept of integers and divisors, and
36 | NewScientist | 28 February 2009
instructed to use these to play around with the integers 1 to 10, looking for interesting relationships. A second student had the same concepts and instructions, but played with the integers 11 to 20. Student two generated two new concepts: “even numbers” and “the sum of two primes”. Then it generated a conjecture: that all even numbers can be expressed as the sum of two primes. It thought this was interesting, and sent its work to the teacher to be placed on the agenda for discussion. The response was positive. “The teacher sent a request for modifications to this conjecture, and student one found the counterexample,” Pease says. That counterexample is the number 2: the conjecture was modified to “all even numbers except 2 are the sum of two primes”. The fact that Christian Goldbach came up with this still unproven conjecture in 1742 makes it a little less impressive, but the point is made. Even if computers are a few centuries behind, it seems that machines really can do what human mathematicians do.
looked at, nothing has yet made a big discovery.” At the very least, she says, that means there is a long way to go. Colton thinks there is every reason to believe computers could produce something interesting to mathematicians. “Software is already producing theorems of value to maths,” he points out. “Not of huge value, I admit – but then the average student or mathematician isn’t producing anything of huge value either.” He and his team are convinced that computers can be genuinely creative. “Creativity is a very loaded word: people like to think it’s a uniquely human attribute,” he says. “The fact is, computers doing maths are more likely to be creative than, say, an undergraduate student, in many ways.” Others are sceptical of this view. Computers are a useful tool, says Rafael Núñez an expert on mathematical cognition at the University of California, San Diego, but the sense that computers can invent mathematics is an illusion. Though it looks like we can make progress by programming machines to do mathematics, he reckons there can be nothing in these machines that isn’t pre-ordained by human mathematical concepts. “For me, it’s like computing the decimal places of pi,” Núñez says. “Once we have decided what the right rules are, we’re just using the computer to crunch numbers.” Sloman thinks Núñez’s view is too narrow. He points to “evolutionary algorithms” as a reason for optimism. This innovation allows a computer to evolve its own programs by producing lots of them, testing them against a goal criteria, and then selecting and “interbreeding” the best ones. It has allowed computers do things that nobody programmed them to do. “In some cases no human even knows how they do what they do,” Sloman says. Aerospace and automobile designers have been using evolutionary algorithms since the late 1980s to optimise aircraft parts and streamline their designs. Even city traders are using them to buy and sell shares ( New Scientist, 28 July 2007, p 26). Evolution has a few million years head start on us in developing brilliant mathematicians, of course, but at least we’re now in the race. “Our big discovery would be how do we do mathematics, rather than how do we write a program that can generate really new mathematics,” says Pease. “But hopefully one would lead on from the other.” ■ Michael Brooks is writer based in Lewes, UK, and author of 13 Things That Don’t Make Sense (Profile)
Why do people die that way? A grand theory of suicide promises to answer this question once and for all, says Robert Pool
OR a few months in late 2006 and early 2007, the woman who called herself kristi4 was one of the best-known members of the pro-anorexia community. As the administrator of a blog on LiveJournal.com, she dispensed advice, encouraged others and wrote candidly about her own struggles. Then, late one Friday night, after a series of entries describing what she was planning to do, kristi4 killed herself with an overdose of prescription sleeping pills, muscle relaxants and painkillers. Her death was just one tragic data point in one of the most striking statistics in all of psychology. It has long been known that anorexia has the highest death rate of any mental illness: one out of every five people with anorexia eventually die of causes related to the disease. What has only now been recognised, however, is that a huge number of those deaths are from suicide rather than starvation. Someone who develops anorexia is 50 to 60 times more likely to kill themselves than people in the
million Approximate number of suicides worldwide each year
general population. No other group has a suicide rate anywhere near as high (Archives of General Psychiatry, vol 60, p 179). Recently, psychologists have tried to explain why anorexia and suicide are so intimately connected, something which is helping to answer the wider question of why anyone would commit suicide. If this explanation holds up, it will give psychiatrists a new tool for screening patients and determining which of them are most likely to kill themselves, perhaps saving lives. Suicide has always been a conundrum for psychologists and other researchers interested in human behaviour. Self-preservation is one of the strongest human instincts, so the drive to commit suicide must be even more powerful. But what causes it? A century ago, both the sociologist Emile Durkheim and the psychoanalyst Sigmund Freud came up with sweeping explanations. Durkheim, not surprisingly, saw the roots of suicide in social factors, such as a failure to integrate into society, while Freud rooted his explanation in instinctual drives, particularly what he called the death instinct. More recent explanations have tended to focus on factors such as depression, hopelessness and emotional pain, but none of them have had much success in answering the fundamental question about suicide: why do some people kill themselves while others in seemingly identical circumstances do not? Some progress has been made by crunching large amounts of data on suicide, says Harvard University psychologist Matthew Nock, who studies suicide and selfharm. Researchers have learned, for example, that suicide rates are rising and now account for 1.5 per cent of all deaths worldwide. > 28 February 2009 | NewScientist | 37
seconds somebody dies by suicide
38 | NewScientist | 28 February 2009
hopeless. First, they must have a serious desire to die. This usually comes about when people feel they are an intolerable burden on others, while also feeling isolated from people who might provide a sense of belonging. Second, and most important, people who succeed in killing themselves must be capable of doing the deed. This may sound obvious, but until Joiner pointed it out, no one had tried to figure out why some people are able to go through with it when most are not. No matter how seriously you want to die, Joiner says, it is not an easy thing to do. Global tragedy While some countries have a higher suicide rate than others, worldwide the rate has increased markedly since 1950
6.5 - 12
20 15 10
<6 No data per 100,000 people in 2007
0 1950 1960 1970 1980 1990 2000
Rates per 100,000 people per year
Suicide is the second leading cause of death among people aged 15 to 24, after vehicle accidents. Women are more likely than men to attempt suicide, while men are much more likely to succeed. Most people who commit suicide have a mental disorder – anorexia, major depressive disorder, bipolar disorder, schizophrenia and borderline personality disorder are the most common, but an elevated suicide risk is part and parcel of many of the others, too. People who kill themselves also generally feel deeply depressed and hopeless at the time. What the statistics do not tell us – and what psychologists most want to know – is exactly which people are most at risk. The vast majority of depressed, hopeless people do not commit suicide, so why do some do it? In 2005, psychologist Thomas Joiner, a suicide specialist at Florida State University in Tallahassee whose own father committed suicide, set out to answer that question. By studying suicide statistics and paying particular attention to the groups with above average rates, Joiner believes he has found a common thread others have missed. “It was the first grand theory of suicide in quite a while,” says Nock. In essence, Joiner proposed that people who kill themselves must meet two sets of conditions on top of feeling depressed and
The self-preservation instinct is too strong. There are two ways people who want to die develop the ability to override the selfpreservation instinct, Joiner argues. One is by working up to it. In many cases a first suicide attempt is tentative, with shallow cuts or a mild overdose. It is only after multiple attempts that the actions are fatal. The other is to become accustomed to painful or scary experiences. Soldiers and police who have been shot at or seen their colleagues injured or killed are known to become inured to the idea of their own death. Both groups also have a higher-than-normal suicide rate. Similarly, doctors and surgeons who witness pain, injury and death are more likely to be able to contemplate it for themselves – the suicide rate for doctors is significantly higher than for the general population. Joiner describes this as a “steeliness” in the face of things that would intimidate most people. Another group that displays steeliness are people with anorexia. Joiner had noted their heightened suicide rate in his original work, Why people die by suicide (Harvard University Press, 2005), but it wasn’t until later that he grasped the importance of the connection. That realisation began to dawn in 2006, during a seminar in which two of Joiner’s graduate students, Jill Holm-Denoma and Tracy Witte, were listening to him describe the risk of suicide among people with anorexia. Witte observed that the high suicide rate had two possible explanations. Perhaps people with anorexia were no more likely to attempt suicide than people with other mental disorders, but the anorexia had so weakened their bodies that their suicide attempts were more likely to succeed. Alternatively, perhaps anorexia had so inured them to pain that
they were more capable than others of doing what was necessary to kill themselves. According to Joiner’s hypothesis, the second explanation should be correct. So Holm-Denoma set out to test the prediction. She examined nine suicides chosen randomly, and what she found told a very clear story. “These people would have died regardless of their body weight,” she says. “We were just astounded by the lengths to which they went to make sure they were successful.” Three jumped in front of trains. Two hung themselves. Two took large drug overdoses. One poisoned herself with sleeping pills and toilet bowl cleaner. And one locked herself in a gas station restroom and set fire to a trash can that produced enough carbon monoxide to asphyxiate her. Nine cases, of course, are not enough to prove the point, but the fact that all took such drastic measures to kill themselves says something (Journal of Affective Disorders, vol 107, p 231). Anorexia offers a “perfect storm” of the factors laid out in Joiner’s hypothesis, Holm-Denoma says. Social isolation is likely because people with anorexia avoid any interactions that might involve food – so that means not going out for a meal, no movies (the popcorn might be too tempting) and no stopping by a friend’s house. The result is the “thwarted belongingness” that Joiner describes as a key factor in suicide. Then there is the feeling that they have
60 become an intolerable burden to their family and friends. One popular approach to treating anorexia in children, for example, involves having a parent oversee their child full-time. Most importantly, anorexia means becoming inured to pain. Merciless starvation leads to intense and painful hunger pangs and major headaches. Osteoporosis is common, making fractures more likely, not to mention the chest pains caused by heart damage. Kristi4’s blogs in the month leading up to her suicide show this perfect storm at work. It is one of the strengths of Joiner’s explanation, says Nock, that it makes testable predictions such as the one spotted by Witte. For example, it should be possible to develop psychological tests to measure how much of a burden people feel, or how thwarted, and then use them to predict who will commit suicide. It should also be possible to examine rates of
Number of failed suicide attempts for each successful one
per cent increase in worldwide suicide rates since 1965 suicide among various groups with the characteristics Joiner is talking about. Those tests are slowly taking shape. Recent work by some of Joiner’s students has shown that people who feel they are a burden and also experience thwarted belongingness are more likely to have suicidal thoughts (Journal of Consulting and Clinical Psychology, vol 76, p 72). A second study found that “painful and provocative events”, such as shooting a gun or getting into a fight, tend to increase something Joiner calls “acquired capability” – a written test that measures someone’s ability to hurt or kill themselves. Meanwhile, University of Minnesota psychiatrist Scott Crow has studied suicide rates among people with bulimia and found that they, too, kill themselves at a much higher rate than the general population. Crow has found a four to six-fold increase in suicides in this group. Bulimia starves the body at some level, as indicated by various biochemical markers, so people with bulimia may well be inured to pain in much the same way as those with anorexia. Even though the evidence is all pointing in the same direction, Joiner says many more tests will be needed before his ideas can be accepted as a general explanation for suicide. “It’s a start,” he says of the evidence assembled to date. “But we need something much more systematic.” Ultimately, he says, a better understanding of why people commit suicide should help clinicians better assess who is most at risk, and find new ways of preventing people from killing themselves. Long-term psychotherapy, for instance, could help chip away at a person’s fearlessness and lessen the likelihood that they will commit suicide. But as long as people steel themselves to pain, as long as they feel isolated and a burden to others, Joiner’s theory predicts that suicide will be with us as well. ■ Robert Pool is a writer based in Tallahassee, Florida 28 February 2009 | NewScientist | 39
TAND on the banks of the Rhine where it flows into the North Sea, near the port of Rotterdam in the Netherlands, and you’ll witness a vast, untapped source of energy swirling in the estuary. According to Dutch engineer Joost Veerman, it’s possible to tap this energy without damaging the environment or disrupting the river’s busy shipping. For rather than constructing a huge barrage or dotting the river bed with turbines, Veerman and his colleagues at Wetsus, the Dutch Centre for Sustainable Water Technology in Leeuwarden, believe they can tap energy locked up in the North Sea’s saltwater by channelling it, along with fresh water from the Rhine, into a novel kind of battery. With a large enough array of these batteries, he says, the estuary could easily
solution Energy on tap, wherever the river meets the sea
The seaside may be the perfect spot for a new generation of green power plants, says Kate Ravilious 40 | NewScientist | 28 February 2009
Clean current Engineers are testing two competing technologies for combining sea water and river water to generate electricity. These salinity power generators could eventually supply electricity at costs comparable to other renewable sources
STATKRAFT’S PRESSURE RETARDED OSMOSIS POWER GENERATOR
BRACKISH WATER OUT SEA WATER IN
BRACKISH WATER OUT
SEA WATER IN
Sodium ions Chloride ions
FRESH WATER IN
FRESH WATER OUT FRESH WATER IN BRACKISH WATER OUT CURRENT
Salt and fresh water separated by semipermeable membrane
Uses two kinds of membrane – one permeable to positive sodium ions, the other permeable to negative chloride ions
Osmosis draws fresh water to the salty side
Both membranes impermeable to water and stacked in alternate layers
This increases pressure, pushing the salt water through a turbine
Sea water flows along one side of each membrane, fresh water along the other Na+ ions move to cathode, Cl- move to anode A voltage is generated across the cell
COMPARING THE COSTS OF ELECTRICITY GENERATION Estimated ultimate cost
Photovoltaic cells – crystalline silicon Solar thermal – parabolic trough Biomass - municipal solid waste Wind – offshore Wind – onshore Reverse electrodialysis Pressure retarded osmosis Geothermal – binary cycle plant Geothermal – flash steam plant Natural gas Coal 0
Cost ($ per megawatt-hour)
His plan was to harvest power where rivers meet the ocean, close to the point where fresh water meets salt. Fresh water would be piped to a generating plant from upstream and saltwater from downstream. Inside the plant, the fresh and saltwater would be channelled along either side of a membrane. Osmosis would then provide sufficient water pressure on the salty side of the membrane – up to 12 atmospheres, Loeb reckoned – to make electricity generation profitable. The key lay in finding the right membrane. It would have to be permeable to water but not salt, and very thin yet extremely durable. This proved too tall an order and Loeb retired in 1986, his dream unrealised. The concept was revived in 1997, when Thor Thorsen and Torleif Holt, working in
Trondheim at the Norwegian research organisation SINTEF, became convinced that membrane technology was finally advanced enough to make Loeb’s idea feasible. With their enthusiasm, and detailed calculations, they convinced Statkraft that salinity power could pay off in Norway. Using a design much like Loeb’s original, they now believe they are close to their goal. Membrane development remains the biggest headache, says Stein Erik Skilhagen, manager of the PRO project at Statkraft. Unfortunately, membranes used in desalination plants are too thick, he says, and cannot draw enough water through. So Statkraft’s engineers have been working with membrane developers to improve designs. While their first membranes generated > 28 February 2009 | NewScientist | 41
SOURCE: STATKRAFT / NEW ENERGY FINANCE / WETSUS
provide over a gigawatt of electricity by a process they’ve called Blue Energy – enough to supply about 650,000 homes. “Salinity power” exploits the chemical differences between salt and fresh water, and this project only hints at the technology’s potential: from the mouth of the Ganges to the Mississippi delta, almost every large estuary could produce a constant flow of green electricity, day and night, rain or shine, without damaging sensitive ecosystems or threatening fisheries (see map, page 43). One estimate has it that salinity power could eventually become a serious power player, supplying as much as 7 per cent of today’s global energy needs. In an attempt to prove that this isn’t just a pipe dream, Veerman’s team has done lab tests on a prototype salinity power generator, and are now planning to scale it up. Yet a group of Norwegian engineers have gone one stage further, with their own twist on salinity power. In the next few months, engineers at Norwegian power company Statkraft plan to throw the switch on the world’s first salinity power station. Though their prototype is small, its impact could be huge. So what are these rival technologies, how do they stack up, and what are the obstacles to making electricity wherever rivers meet the sea? Salinity power emerged from a rather different use for sea water. In the late 1950s, Sidney Loeb and Srinivasa Sourirajan, then working at the University of California, Los Angeles, came up with a new trick to extract drinking water from the sea. Their idea was based on osmosis, a natural process in which water passes spontaneously from a dilute to a concentrated solution through a semipermeable membrane. The pair realised that by using a synthetic membrane and high pressure pumps, they could run osmosis in reverse and literally squeeze fresh water from sea water. This approach is now used in desalination plants worldwide. About 15 years later, Loeb had another brain wave. He realised that their design could be exploited to generate power. Working at BenGurion University of the Negev, in Beer Sheva, Israel, he envisaged a tank with two chambers separated by a semipermeable membrane. With saltwater on one side and fresh on the other, osmosis would draw fresh water into the salty side, raising its pressure. This pressurised saltwater could then be piped through a turbine to generate electricity (see diagram). Loeb named this process pressure retarded osmosis (PRO) and patented it in 1973.
WETSUS’S REVERSE ELECTRODIALYSIS POWER CELL
about 100 milliwatts per square metre, the latest version generates over 3 watts per square metre, close to their target of 5 watts. Skilhagen reckons these membranes are now efficient enough to be worth testing beyond the lab, and in the next few months the company plans to turn on the world’s first prototype PRO plant at the Södra Cell paper pulp factory in Tofte, alongside a fjord 60 kilometres from Oslo.
it should be possible to pipe in the fresh water using gravity alone. Build the power plant underground or on the river bed and gravity will also bring in the saltwater, says Skilhagen. The Tofte plant will generate about 4 kilowatts, though a fifth will be used for pumping the water. The rest – just over 3 kilowatts – is only enough to power a couple of kettles, but Statkraft hopes to construct a large scale salinity power plant by around
”Blue Energy could provide up to 7 per cent of global energy needs by exploiting around half the flow in the world’s largest rivers” The prototype will provide crucial experience in scaling up the system. The new plant fits inside a room no bigger than a tennis court. “In the lab, our membrane had the footprint of a coffee cup. At Tofte we will be using 2000 square metres of the stuff,” says Holt. A full-scale plant will need millions of square metres of membrane, so maximising the surface area for exchange is crucial, he says. The team is testing two designs. In the first, a long membrane tube is rolled up lengthways into a spiral something like a Swiss roll. Fresh water is pumped through the tube, while saltwater is pumped around the tube on the outside. Each spiral roll is less than 1 millimetre in diameter, and hundreds are arranged in parallel inside a pipe about 20 centimetres across. In the alternative design, the membrane is made into straight tubes which run through a tank of saltwater. Fresh water is pumped along the membrane tubes.
Help from gravity As well as finding the optimal way to pack the membranes together, the researchers must work out how to prevent the delicate pores from clogging with silt and algae in the water. They are looking at an anti-fouling coating to put on the membrane, and experimenting with reversing the flow periodically to flush silt out, says Holt. The other challenge will be to minimise the energy used to bring the water into the plant. Lab tests show a fifth of the electricity generated was expended on pumping the water in. However, many of Norway’s rivers drop steeply from the mountains, so in future 42 | NewScientist | 28 February 2009
2015. This will be about the size of a football stadium, contain 5 million square metres of membrane and generate about 25 megawatts of electricity, they say, incorporating a new membrane and efficiencies of scale. It should power more than 15,000 households. Statkraft calculates that salinity power could eventually provide Norway with up to 12 terrawatt-hours of electricity annually, roughly 10 per cent of the country’s consumption. “We estimate the global potential to be 1600 to 1700 terrawatt-hours annually,” says Skilhagen, about 1 per cent of the world’s annual energy needs. This would mean using about half of the fresh water flowing through every large estuary. There is some scepticism that Statkraft’s technology can be rolled out globally. Norwegian rivers are relatively clear of mud and silt, says Veerman. “In other parts of the world such as the Netherlands and the UK there is lots of silt and bacteria in the rivers.” The cost of cleaning up this water makes PRO a non-starter, he says. So Veerman and his colleagues at Wetsus have devised a rival system – a salt-based battery. Dubbed Blue Energy, it generates electricity by moving ions rather than water molecules across membranes. Their membranes are along the same lines as those used in kidney dialysis machines. In fact, their system requires two kinds of membrane – one permeable to positive ions, the other to negative ions. Both are impermeable to water. Typical sea water contains about 35 grams of salt per litre, so compared with fresh water it is packed with positively charged sodium ions and negatively charged chloride ions.
The team placed alternating layers of their two membranes in a stack to create separate chambers. When fresh water and saltwater flows simultaneously across alternate chambers, chloride ions flow spontaneously from the saltwater through one membrane into the fresh water, while sodium ions flow through the other membrane in the opposite direction (see diagram, page 41). This movement of ions generates a potential difference between a pair of electrodes, placed at either end of the cell. Veerman and his colleagues have already switched on a small prototype Blue Energy generator in their lab. Though it only produces 20 watts of power, this convinced Pieter Hack, director of Dutch company Magneto, to form a new company called Redstack, which will commercialise the technology. Now Redstack and Wetsus are collaborating on a pilot project, at a salt mine in Harlingen in the northern Netherlands. Salty waste water from the mine and fresh water from the local river are piped into the pilot plant, with each pipe feeding the rows of salt or fresh water channels inside the salt batteries. The unit – the size of three washing machines – is due to be switched on in weeks, and should produce several kilowatts of power. Unlike Statkraft’s Tofte plant, this one isn’t linked to the electricity grid, but will help the researchers assess how Blue Energy can be scaled up. Membrane design is still an issue. The water-flow rate must also be optimised. But since only ions cross the membrane, there is less mass flowing across the membrane than with their rival’s technology, and so silting
A tenth of the Amazon’s flow could provide 50 gigawatts of electricity
Global maximum Salinity power generators could provide several thousand terrawatt-hours of electricity annually, supplying up to 40 per cent of the world’s electricity demand
YENISEI 44 gigawatts
MACKENZIE 23 gigawatts
problems are reduced, Veerman says. Veerman and his colleagues calculate that if all the rivers of sufficient size in the Netherlands were utilised, Blue Energy could provide as much as 75 per cent of the country’s electricity needs. By exploiting around half of the water flowing in the world’s largest rivers, they estimate that Blue Energy could provide up to 7 per cent of the world’s energy needs. Skilhagen thinks this figure is optimistic. “They haven’t accounted for the seasonal variations in river flow, and environmental considerations.” In theory, the Rhine can deliver 5 gigawatts of electricity. In practice, Skilhagen says, it would be impossible to block or divert the river’s entire flow without doing serious environmental and economic damage. Yet Veerman estimates that using around onefifth of its flow would be acceptable, providing around 7000 gigawatt-hours of electricity annually through Blue Energy.
RHINE 5 gigawatts MISSISSIPPI/MISSOURI 37 gigawatts
NILE 11 gigawatts
AMAZON 500 gigawatts – the equivalent of about 100 large power stations
YANGTZE 73 gigawatts GANGES 32 gigawatts
MEKONG 37 gigawatts
MURRAY/DARLING 2 gigawatts Maximum theoretical output (assumes every plant generates 2 megawatts per cubic metre of river water, and that the entire river flow is utilised)
Keep it clean
JACQUES DESCLOITRES, MODIS, NASA/GSFC
What of other impacts on the environment? The process generates brackish water, but this could simply be pumped or channelled into the sea. And each plant requires pipelines to collect and discharge water, as well as pylons to carry electricity to the grid. Large rivers often have industrial ports where they meet the coast and plants could be built in such areas, says Skilhagen. They already have much of the necessary infrastructure, too. “I’d be surprised if there are no environmental problems, but we are not aware of any right now,” he says. “This is why it is important for
us to build this prototype and ensure that it has minimal impact on the environment.” Both teams aim to learn these lessons quickly; though outwardly complimentary about each other’s work, there is a clear element of competition. Both technologies are at a similar stage and the first to prove their design can be profitable without damaging the environment could have a serious advantage in the marketplace. River estuaries are not the only place where salinity power can be set to work. Power could be generated at desalination plants using leftover brine, or with waste brine from industrial processes or salt mines. The Dutch team’s master plan, though, is to use the Afsluitdijk dam which separates the Ijsselmeer from the North Sea in the central Netherlands. The IJsselmeer is the largest lake in western Europe, covering an area of 1100 square kilometres. Fed by the river IJssel, its level rises by around 4 centimetres each day. This is insufficient for hydroelectric power, and the excess is currently emptied into the North Sea. However, the sluice gates on the Afsluitdijk dam are perfect for feeding water past ionic membranes in a salinity power plant, says Veerman. This could create perhaps hundreds of megawatts for short periods, at times of peak demand. “We could use this lake as an energy buffer, in combination with wind energy,” says Veerman. The Dutch team are applying for permits to begin this project. Compared to conventional energy generators, the capital cost of a salinity power plant is high, but likely to drop significantly once the technology is proven. Hack estimates that it would cost over $600 million to
construct a 200-megawatt salinity power plant covering the area of two soccer pitches at the Afsluitdijk dam, and that this plant would produce electricity at a retail cost of $90 per megawatt-hour. Statkraft won’t reveal detailed figures, but are aiming to produce electricity at a retail price of between $65 and $125 per megawatt hour by 2015. By comparison, modern fossil-fuel power stations churn out electricity at a cost of about $50 per MWh. Roelof Schuiling, a geoengineer at Utrecht University in the Netherlands, believes that both types of salinity power projects are feasible and could play a valuable global role. “If realised, it is more dependable than wind energy and could have a big impact on our energy sources,” he says. For example, a typical wind turbine is reckoned to generate electricity for an average of 3500 hours each year. A salinity power plant, on the other hand, could operate close to full capacity for more than 7000 hours a year. Will salinity power ever pulse down the power lines? By May this year, when Statkraft flicks the switch at their pilot plant, the technology’s true potential should become clearer. “We don’t claim that salinity power will be the global energy solution,” says Skilhagen, “but it could play an important role, and ensure that we hand over a better world to our children.” Unfortunately, Loeb won’t be there to witness the event: he died in December 2008, aged 92. “He had a lot of interest in our work until his last days, and his wife still follows our efforts,” says Skilhagen. ■ Kate Ravilious is a science writer based in York, UK 28 February 2009 | NewScientist | 43
SOURCE: SAMHSA, VERISPAN
CONGO 96 gigawatts
MEGHNA (Bay of Bengal) 91 gigawatts
BOOKS & ARTS
Say hello to the chickenosaurus Can we rewind evolution, turning the humble chicken into a dinosaur? of an older embryo before it turned into a stunted pygostyle. The experiment didn’t work, a failure that points to the tremendous complexity of the development process. We don’t yet know how to coax out a chicken’s inner dinosaur, but for Horner, it’s a worthwhile quest. Horner’s dream is to walk on stage on The Oprah Winfrey Show with chickenosaurus following him on a leash, but he wants more
How to Build a Dinosaur: Extinction doesn’t have to be forever by Jack Horner and James Gorman, Dutton, $25.95 Reviewed by Jeff Hecht
44 | NewScientist | 28 February 2009
“Horner proposes altering gene regulation so the chicken embryo would grow a long dinosaur tail”
JACK HORNER wants to raise the dead by growing a dinosaur from a chicken embryo. The publisher calls his idea “astonishing new science that trumps science fiction”. Has palaeontologist Horner’s stint as a consultant on the Jurassic Park films infected him with some science-fictional virus? Is chickenosaurus his bid to create a new monster-movie franchise? Fortunately, it’s “no” to both questions. In How to Build a Dinosaur Horner is at his best: provocative yet firmly grounded in science. I doubt he’d mind hitting the bestseller list, but his goal is to make people think about how evolution works, and by extension, about our own origins. Science holds out some hope for cloning ancient DNA and resurrecting the victims of recent extinctions, from dodos and moas to mammoths and woolly rhinos. But for dinosaurs, it doesn’t look promising. Horner’s former student Mary Schweitzer, for example, has extracted traces of protein and possibly soft tissue from the extremely well-preserved leg bone of a Tyrannosaurus rex that died more than 65 million years ago. DNA is far less stable than protein, so if the protein was scarce, Horner sees no chance that enough DNA survives to clone the extinct giants. So much for Jurassic Park. Happily, Horner thinks there’s
Every chicken has an inner dinosaur but coaxing it out is another matter
a different way to build dinosaurs, and it doesn’t involve finding any fossil DNA. He wants to alter the embryological development of chickens, which are living descendants of dinosaurs. His idea comes from the fertile field of “evo-devo”, which focuses on how evolution affects the way animals develop from fertilised eggs. Look closely at a developing embryo and you can see some ancestral forms briefly appear. Birds, for example, start to develop tails, then convert the would-be-tail into a pygostyle, a bony lump at the base of the spine which holds the tail feathers. Careful study of this process
reveals that two sets of genes are involved, one controlling the expression of the other. There are the genes to build tail bones plus additional genes to transform the tail bone into other structures. Crucially, evolution most often affects the latter “control” genes. That led Horner to propose altering the chicken embryo so that it would grow a long tail, like those seen in dinosaurs or in Archaeopteryx, the earliest known bird, as well as other ancestral traits such as claws and teeth. With Horner’s encouragement, Hans Larsson of McGill University in Montreal, Canada, thought he might be able to grow a dinosaurian tail on a chick by splicing the fast-growing tail tip from a young embryo onto the tail
than fame. A dino-chicken, he writes, “would be shockingly vivid evidence of the reality of evolution… The creature would be its own sound and vision-bite”. It wouldn’t be the first experiment in evolution – we live among uncontrolled examples including microbial response to antibiotics and insect resistance to pesticides – but it would be the first rewinding of evolution, the first time we could watch it happening in reverse. Linking the most charismatic of fossils with the humble barnyard chicken would make a great scientific story. It would show how molecular changes bring about the large-scale differences in form seen throughout the fossil record. It would teach us about birds, dinosaurs and evolution. Co-authored by James Gorman, deputy science editor of The New York Times, this book makes for a good read, whether or not a chickenosaurus ever hatches. ■ Jeff Hecht is a regular contributor to New Scientist
N.A.SHARP, NOAO/NSO/KITT PEAK FTS/AURA/NSF
For more reviews and galleries go to www.NewScientist.com/topic/books-art
Light of life This is what visible light from the sun looks like if you split it into its constituent colours. But playing with a prism at home will not give you this high-resolution masterpiece, which was created using a sophisticated spectrometer fixed to the world’s largest solar telescope at the Kitt Peak National Observatory in Tucson, Arizona. The spectrometer splits light from the sun into two beams and sends them towards two mirrors, which bounce the light back to a detector where the beams recombine.
Via a complex mathematical technique, the resulting interference pattern appears as a spectacular solar spectrum, covering the entire range of visible light. What are the dark blobs in the image? These are known as Fraunhofer lines after German physicist Joseph von Fraunhofer, who first studied them in detail in 1814. They are caused by specific elements in the outer layers of the sun absorbing a characteristic wavelength of light – the missing wavelength showing up as a dark
line. This barcode-like image tells us about the elements present in the sun. For instance, the broad dark patch in the red part of the spectrum (upper right) indicates the presence of hydrogen and the two prominent lines in the yellow part are sodium. As well as helping us to study the chemical composition of stars, such spectra can also tell us about the atmosphere of planets orbiting other stars. Astronomers first collect the spectrum when the planet is behind its host star, then when the planet passes in front. Subtract the
first from the second, and you get the spectrum of the planet. If we find other Earth-like planets in a star’s habitable zone, astronomers can study their spectra to look for water vapour, oxygen or methane in the planet’s atmosphere – all tantalising hints of life elsewhere. Anil Ananthaswamy ■ You can find this image in Hidden Universe by Lars Lindberg Christensen, Robert Fosbury and Robert Hurt, Wiley-VCH $29.95/£16.99
28 February 2009 | NewScientist | 45
BOOKS & ARTS Matter’s doppelgänger
No more drink
How one man went to extraordinary lengths to conquer his addiction
The End of My Addiction by Olivier Ameisen, Farrar, Straus and Giroux/ Piatkus, $25/£11.99 Reviewed by Clare Wilson
AS a cardiologist, Olivier Ameisen was familiar with hospitals, but not being detained in a psychiatric ward. Being committed to a New York hospital after yet another drinking binge was one of the many low points in his sevenyear struggle with alcoholism. The End of My Addiction is the fascinating tale of how he found his own cure through a bout of pharmacological trial and error. Standard drug treatments for alcoholism and endless AA meetings hadn’t helped Ameisen. He lost his job and his girlfriend, and in his forties had to move back home with his mother in France. Then he heard of a medicine called baclofen, long46 | NewScientist | 28 February 2009
used safely as a muscle relaxant, which animal research and a few anecdotal reports from cocaine users suggested reduced drug cravings. While in France, he began self-prescribing and found that at the standard dose his cravings for alcohol lessened. Desperate for a complete cure, he upped his dose beyond the medical recommendation and found his cravings eliminated. He has been sober for five years. One person’s experience isn’t, of course, proof of a cure. For that you would need large randomised trials, though the results of one small 12-week trial were promising (The Lancet, vol 370, p 1915). But this engaging account does give interesting insights into the toll this disease can take and shows how, at least in this case, it was possible to fight back. It also explores the science behind baclofen’s possible mechanism of action, and why it may be useful against other addictions.
Antimatter by Frank Close, Oxford University Press, £9.99/$19.95 Reviewed by Amanda Gefter
LIKE the universe in Alice’s looking glass, there exists a mirror world to our own – an antiworld built from antiparticles that congregate into antiatoms, antimolecules and possibly even antilife. This is the world of antimatter, and there could be no better guide to its strange landscape than physicist Frank Close. In this beautifully written book, Close elucidates the mysteries behind matter’s doppelgänger – from its theoretical underpinnings, to its experimental triumphs, and its practical applications, such as the use of antiparticles in brain imaging technology. Close explains how to tell if an alien civilisation is made of antimatter and why antimatter bombs remain science fiction, despite the US military’s interest in them. Ultimately, antimatter holds the secret to why there is any matter at all. This book will inspire a sense of awe in even the most seasoned readers of physics books.
Heavens above Decoding the Heavens by Jo Marchant, Da Capo Press, $25 Reviewed by Paul Collins
TO THE untrained eye, the first analogue computer wasn’t much to look at. Retrieved from a 1st century BC Greek shipwreck, the Antikythera mechanism resembled “a green, flaky pastry”, albeit one with a filling of gears inscribed with enigmatic lettering. Jo Marchant, a consultant for this magazine,
tells a fascinating tale of an artifact that upends our estimation of Classical technology. Ignored, misinterpreted and even fobbed off as “alien technology”, it has taken a century to fully recognise the extraordinary gearwork’s purpose in tracking planetary motion. Amid the hazardous dives that raised it and the lives spent in painstaking research and professional jealousy, Decoding the Heavens conveys the wonder of a find one archaeologist hailed “as spectacular as if the opening of Tutankhamen’s tomb had revealed the decayed but recognisable parts of an internal combustion engine”.
Come doomsday The Vanishing Face of Gaia by James Lovelock, Allen Lane, £20 Reviewed by Andrew Robinson
THE financial crash may help sales of James Lovelock’s second volume on Gaia. If it happened to the economy, why not to climate? Both systems are “complex and nonlinear and can change suddenly and unexpectedly”, he writes. He lacks confidence in climate models with their smoothly rising curves of global temperature up to 2100, and instead anticipates a sudden flip to a state 5°C as hot. Since it is too late to prevent this, we must think about how to adapt and act fast. The best chapters concern survival strategies, such as energy and food options for the UK, which will become a “lifeboat” for environmental refugees. Published simultaneously, He Knew He Was Right, an authorised biography of Lovelock by John Gribbin and Mary Gribbin, demonstrates well how Gaia has overcome its main critics to become part of a distinguished historical tradition of serious if controversial science.
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The paper is actually about fish, Ben tells us, and the vocalisations are of the low-frequency variety, making Bass a rare example of double nominative determinism.
READER Laurel Daniel says she knows we have said we don’t want any more examples of nominative determinism, but she still thinks we might be interested in the convergence of name and talent demonstrated by Jolee Bacon, the Idaho woman who won first place in the Nez Perce County Fair hog-calling contest. A short trawl of a famous web search engine (FWSE) reveals that 2008 was the first year that women – not only Jolee Bacon of Idaho (www.joleebacon.notlong. com) but also Doris Probst of Illinois (www.dorisprobst. notlong.com) – started to beat men in these hog-calling contests, which involve squealing, oinking, snorting and generally making noises like a pig. We were pleased to learn this, and we were also pleased to be informed by Meredith Lloyd-
Evans that he recently came across the headline “Swine Vets Invited to Apply for Hogg Scholarship”. This was followed by the explanation: “The American Association of Swine Veterinarians Foundation is to offer the Hogg Scholarship, established to honour the memory of longtime AASV member and swine industry leader, Dr Alex Hogg.” Meredith tells us that this information was “gleaned in surprise” not from the FWSE but from www.thepigsite.com, which is a mine of information about all things swiney. Turning to something quite different, Ben Haller tells us of a paper in Science (vol 321, p 417) entitled “Evolutionary origins for social vocalization in a vertebrate hindbrain-spinal compartment” one of whose authors is A. H. Bass.
“Philip Hole felt the message he received from Scottish Power was a bit back-to-front: “If you receive this email by mistake, please delete it then advise the sender immediately by reply email” 76 | NewScientist | 28 February 2009
THE latest unusual unit to join the Titanic (weight), the Wales (area), the Olympic swimming pool (volume), the African elephant (large size) and the Kylie Minogue (small size) is the kiloSteve (Steves), which was coined this month by Project Steve. In a parody of creationist lists of “scientists against evolution”, Project Steve has been gathering names of scientists in favour of evolution – as long as their name is Steve (or equivalent). The thousandth such Steve has now signed up, hence the kiloSteve. We are sure this new unit will be invaluable in enabling people to comprehend large quantities of Steves. It could also highlight a dangerous decline in their number. The current population of Steves in the US is 2924 kiloSteves (according to the 1990 census, and including Stevens, Stephens, Steves, Stephanies and Stefanies). But the
birth rate in 2005 was a mere 12.8 kiloSteves per year, far short of replacement level. This becomes more serious if you consider that when the census was taken, the US population density was a scant 304 nanoSteves per square metre. It is with sadness that we note in conclusion that while the Henry is a well established SI unit (measuring inductance), the Système International does not yet employ the Steve or its derived units. However,
stephanometrology is a young science so hope remains that it will soon be given proper recognition.
ON THE TV dinner that Hanne Pederson bought at a Sainsbury’s supermarket was a guarantee saying: “We’re sure you’ll love this product. If you don’t, simply return for a full refund.” Hanne points out that this offer implies they are not so sure the product will be loved after all, to which Feedback adds, delicately: “How pristine does it have to be for them to accept a return?” “I did think of that as well,” says Hanne. “If you decide you don’t like the meal, it implies that you have eaten it already. In that case, there is only one way of returning it that I can think of, and it’s not going to go down well at the customer help desk.”
A PIECE of paper floats to the surface of our filing system from 2008, and we find Emily Ackerman telling us about an advertisement in the medical section of Woman & Home magazine offering trips to a clinic in Bratislava for orthopaedic surgery: ”We are offering hip and knee replacements, keyhole surgery, replacement of any other limbs you might have a problem with.” Emily wonders which limbs they have in mind, how they are going to replace them, “and, er, what with?”
FINALLY, Sam Joyce-Farley was surprised and a little disturbed at the claim on his pack of Oberto dried beef jerky. The pack told him: “The meat contained herein… is derived from animals that received ante and postmortem inspection and were found sound and healthy.”
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THE LAST WORD Double trouble
bacteria. It has never actually been inside our bodies. Apart from the bile and one or two other remnants from our exocrine glands, it cannot be regarded as excreta, despite the common use of that word to describe it. Bryn Glover, Cracoe, North Yorkshire, UK
further: rather than having a distinct urinary system, insects rely on malpighian tubules in their digestive systems – outgrowths of the gut that perform the same filtration function as our kidneys. Shaun Hug La Mirada, California, US
Smells fine to me
as disposing of waste products in our bile. The other excreta our bodies produce include tears, earwax, and various secretions associated with our reproductive processes. If young Aisling suffers (or is about to suffer) from spots, then these too are caused by excretions which have gone awry. Our faeces, on the other hand, consist of undigested food and
■ The types of waste we excrete have two different origins. Faeces contains the leftover, indigestible portion of the food we eat, plus bile from the liver, which gives excrement its brown colour. Urine, on the other hand, is the result of blood filtration in the kidneys. Urine contains nitrogenous waste, primarily in the form of urea, which results from the metabolism of nucleic acids and proteins, separate from digestion. Furthermore, urine also contains water and solutes from the blood, and interstitial fluids – these are excreted to maintain water balance. Essentially, faeces are the result of a coarse, large-scale process of the digestive system alone, whereas urine production occurs at a much finer scale, eliminating wastes produced by all the body’s cells. Our two excretory systems are obvious because we have a separate opening for each: the anus and the urethra. In other organisms, the distinction between the systems isn’t as obvious. Animals such as birds, reptiles, and amphibians possess a cloaca, which serves as a common opening for both liquid and solid wastes. Insects blur the line even
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Our daughter Aisling would like to know why we have evolved two bodily systems to excrete waste products. Why do we have to both poo and wee?
■ Strictly speaking, the question is misplaced. We do not “excrete” faeces because our bodies are long fleshy tubes which can be thought of as extremely elongated doughnuts. In a doughnut, one would not consider the hole to be “inside” the cake. Similarly, the tube from our mouth through our gut to our anus is technically “outside” our living body. The process of “excretion” is the passing of material from inside our bodies to the outside. Our kidneys excrete urine, our skin excretes sweat, our lungs excrete water and carbon dioxide, and the inside of our bowel tube excretes many things along its length to assist digestion, as well
“A human is an elongated doughnut: the tube from our mouth to our anus is outside our living body”
After buying a spray-on deodorant, I got home and realised it was intended for women. Nevertheless, not wanting to waste money I used it anyway. Nothing untoward happened and I received no strange looks from colleagues or friends. So what are the differences between deodorants meant for men and those that are meant for women? How might using the “correct” deodorant for your sex work better than using one meant for the opposite sex, and what are the pitfalls of applying a deodorant intended for the opposite sex?
■ The primary function of all deodorants is to inhibit growth of bacteria which feed on secretions from sweat glands. Deodorants are most often differentiated, if at all, by strength. But sex sells, so we have men’s and women’s. They have only three differences: advertising, packaging, and fragrance. Remove fragrance and there are only two differences: advertising and packaging. Formulations for both sexes contain such things as flowers, herbs, spices, fruits and woods, and are judged as suitable entirely by personal and cultural taste. For example, one upscale new fragrance contains citruses, herbs, ylang-ylang, jasmine and tiare flowers, musk, tropical woods and coconut – and it’s for men. And many women buy men’s fragrances, because there is none of the social embarrassment that the reverse carries. A fascinating discussion about fragrance sales and attitudes is online at www. tinyurl.com/bnublk Toshi Knell Nowra, New South Wales, Australia
THIS WEEK’S QUESTIONS BAD SOAP
I found this forgotten bar of soap after winter at my home in northern Sardinia. It had grown a coat of mould (pictured). What is the mould and how did it grow on soap, which is supposed to keep your hands clean? Patrizia Figoli Turchetti Bellaire, Texas, US
Do Polar Bears Get Lonely? A brand new collection serious enquiry, brilliant insight and the hilariously unexpected Available from booksellers and at www.newscientist.com/ polarbears