September 10 - 16, 2016 New Scientist

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YOUNG FOGIES

How some people’s brains resist the ravages of age

SIXTH SENSE

Five basic tastes are not enough

WHALE OF A TIME

Climate change is a boon for cetaceans

WEEKLY September 10 -16, 2016

BEAT FACEBOOK AT ITS OWN GAME Profit from your own data for once

PARTICLES THAT DON’T EXIST

We’re rethinking matter’s most basic building block

No3090 US$5.95 CAN$5.95 3 6

Science and technology news www.newscientist.com US jobs in science

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70989 30690

LINE IN THE SAND Can a 5000 mile hedge hold back the Sahara?

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Professor Dame Carol Robinson 2015 Laureate for United Kingdom

By Brigitte Lacombe

Science needs women

L’ORÉAL UNESCO AWARDS

Dame Carol Robinson, Professor of Chemistry at Oxford University, invented a ground-breaking method for studying how membrane proteins function, which play a critical role in the human body. Throughout the world, exceptional women are at the heart of major scientific advances. For 17 years, L’Oréal has been running the L’Oréal-UNESCO For Women In Science programme, honouring exceptional women from around the world. Over 2000 women from over 100 countries have received our support to continue to move science forward and inspire future generations. JOIN US ON FACEBOOK.COM/FORWOMENINSCIENCE

CONTENTS

Volume 231 No 3090

This issue online newscientist.com/issue/3090

Leader

News

6

3

Artificial ovary created

4

News UPFRONT Mission to grab a bit of asteroid. Ebola lurks in semen for 500 days. Gorillas at risk. Philae finally found. US bee massacre 6 THIS WEEK Strangely burning star helps life in the multiverse. Climate change boost for whales. Superagers have shrink-resistant brains. Nuclear bunker ant colony. Sixth taste is “starchy”. Pollution puts metal into your brain 13 IN BRIEF Blood laser. Brain-bot bat swarms. Childhood inflammation linked to mania. Prozac compound weakens bones. Oldest fossils yet. Hope for Tasmanian devils

JGI/DANIEL GRILL/GETTY

Breakthrough could help women who are infertile

Factual debate needs help, even from AI

On the cover

32

8

Young fogies Resisting age’s ravages 10 Sixth sense Five basic tastes plus one 7 Whale of a time Cetacean climate boon 22 How to beat Facebook Profit from your own data 16 Line in the sand Can a 5000 mile hedge hold back the Sahara?

Particles that don’t exist Rethinking matter’s most basic building block

Analysis 16 The Great Green Wall Can a line of trees across Africa hold back the Sahara desert? 18 COMMENT Zika or not, GM mosquitoes won’t fly. Ban trans fats worldwide to save lives 19 INSIGHT Despite SETI, it’s likely we’ll never hear aliens

Technology 22 Putting your data to work for you. Tracking truckers’ health. The robot guard that can’t stop crime. New theatre of war is digital

Cover image Daniel Stolle

Features

Aperture

36

26 Pharaoh eagle-owl swoops in the desert

Features

Debater bots

29 A bug’s game? The deep truths revealed by bridge-building ants 32 Particles that don’t exist (see above left) 36 Debater bots (see left) 40 PEOPLE Mu-ming Poo and China’s brain project

MORGAN SCHWEITZER

Why we’re teaching computers how to argue

Culture

Coming next week… Forgotten utopia

The mysterious civilisation that lived in peace

Return of cold fusion

42 Fast forward! The idea of time travel has fundamentally changed how we think 43 The Enterprise reloaded Beam up for the birthday voyage of the iconic starship

Regulars 52 LETTERS Searching for second tree of life 56 FEEDBACK Aggressive horses yawn more 57 THE LAST WORD Shape of things to come

Derided science makes a comeback

10 September 2016 | NewScientist | 1

EXPLORE THE QUANTUM WORLD

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Rhetorical devices Reasoned debate needs all the help it can get, even from AI THE descent into a post-truth world continues at a depressing rate. The latest winner of the pants-on-fire award is former US presidential candidate Newt Gingrich. In an interview with CNN after a speech in which Donald Trump wrongly claimed that violent crime was rising, Gingrich cherry-picked the facts – then abandoned them altogether. “The average American does not think crime is down,” he said. “As a political candidate, I’ll go with what people feel.” For those trained in critical thinking, this dismissal of a simple fact is baffling, cynical and scary. How and when did facts lose their currency in public debate? And, more importantly, what we can do about it? The answer to the first question is, in part, technological change. Social media allows people with fringe opinions to hook up with

the like-minded, filter out all competing sources of information and let half-truths, lies and conspiracy theories run riot. Even the mainstream is not immune to this “echo chamber” effect. This is a well-documented phenomenon, and there is plenty of pushback. Organisations such as PolitiFact employ legions of human fact-checkers to rate political statements for their truthfulness. Tech start-ups are designing web browser extensions to automatically check internet pages for their veracity. But all this isn’t working; the forces that have set post-truth politics on the march are too powerful to be halted by mere facts. As Clay Shirkey, an astute commentator on the impact of internet technologies, tweeted after watching his social media feed during Trump’s acceptance speech at the Republican National

Convention: “we’ve brought factcheckers to a culture war”. The weakness of the factual approach is that it tackles only part of the problem. Winning a political argument is about much more than who’s telling the truth. Emotion and authority count just as much if not more. Surprisingly, technology may also be our saviour. AI researchers are working on software that can do much more than check facts: it can also formulate an argument (see page 36), and dissect bad ones to expose the holes. If nothing else such “automated reasoning support” promises a new way to hold powerful people to account, and help people make wellinformed choices. Watch this space for a politician with their pants on fire, spluttering “I think the people of this country have had enough of artificial intelligence…” ■

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you’ll hear about gravitational waves from a member of the LIGO team, learn about black holes, dark matter, dark energy and the theory of everything, as well as the big bang and much more. Book now at newscientist.com/events.

10 September 2016 | NewScientist | 3

NASA/DIMITRI GERONDIDAKIS

UPFRONT Lurking Ebola THE Ebola virus can persist in semen for much longer than we thought. A man in Guinea who survived Ebola in 2014 is now known to have carried it for at least 531 days after, sparking a small outbreak. Ebola virus was known to persist in the testes of survivors, but until now the longest it had been detected surviving in this way was 284 days after recovery. The man contracted Ebola in late 2014. Following medical advice, he abstained from sex for eight months after recovery. But in January 2016 – 470 days since he fell ill – the man had sex with the woman who became the first known case in an outbreak in

“Whether Ebola will re-emerge like this depends on how the virus does this trick”

Mission: to vacuum an asteroid BENNU or bust. On 8 September, the OSIRIS-REx probe will leave Earth for the asteroid Bennu, and will return with souvenirs: up to 2 kilograms of material from its surface. The probe is the latest in a string of sample return missions, following the Stardust mission to the comet Wild 2 and the Hayabusa mission to asteroid Itokawa. Both those missions hit hurdles, and neither brought more than a few grains of material back to Earth. OSIRIS-REx, whose launch rocket is pictured above, will pioneer an ambitious technique for gathering samples: a robotic arm equipped with a vacuum cleaner. It is due to arrive at Bennu in August 2018. Entering a complex orbit around the asteroid, OSIRIS-REx will map its surface and measure its

4 | NewScientist | 10 September 2016

gravity, revealing how the mass inside Bennu is distributed. Radar observations have shown that Bennu is about 510 metres at its widest and that it is probably a “rubble pile” asteroid rather than solid rock, with a texture like compacted styrofoam. This means its gravity is low, making landing difficult. But it also makes it easier to take samples. After about a year of studying Bennu’s surface and selecting the best spot to sample, OSIRIS-REx will swoop to within a few metres of the object, extend its robotic sampling arm to touch the surface for about 5 seconds and suck up between 60 grams and 2 kilograms of rocks and dust, depending on the texture and stickiness of the grains. Once the sample is collected, the probe is set to continue making

observations from orbit until 2021. Then, when our planet and Bennu are well placed for an easy return, OSIRIS-REx will retrace its steps to arrive at Earth in September 2023. The capsule containing the sample is planned to land in Utah. Bennu is a near-Earth asteroid, meaning its orbit crosses Earth’s, and it passes relatively close to us about once every six years. It poses no immediate danger, but might end up on a collision course with us a few centuries from now, especially since light from the sun nudges the asteroid’s orbit over time. Measuring this effect at Bennu will help us understand how sunlight can alter asteroids’ orbits and evaluate the risk they might pose – and work out if we could one day steer them away using the same technique.

Guinea this year. She then spread the virus to nine others (Clinical Infectious Diseases, doi.org/bqbt). What this means for the risk of Ebola re-emerging depends on how the virus performs this trick, and how often, says Andrew Rambaut at the University of Edinburgh, UK, a co-author of the study. “The more time that passes with no further flare-ups, the more likely it is that this case was exceptional.”

Hurricane Hermine GLOBAL warming and rising sea levels may have exacerbated the widespread flooding along the East Coast of the US in the wake of hurricane Hermine. The category 1 hurricane made landfall in Florida on 2 September with wind speeds of 120 kilometres per hour. Contact with land weakened it to a tropical storm, which moved north-east along the coasts of Georgia, South and North Carolina the following day. Despite being relatively weak,

For new stories every day, visit newscientist.com/news

Philae found

Hermine caused significant flooding across the four states affected. Two people died and 400,000 homes lost power. The extent of flooding may be related to higher sea levels stemming from global warming and natural geological processes that are making the US East Coast gradually sink, says Kevin Walsh at the University of Melbourne in Australia. Along parts of the coast, sea levels have risen by 30 centimetres over the last 50 years. One model found that if sea levels rise 1 metre by 2100, hurricanerelated flooding will happen every 3 to 20 years instead of every 100.

60 SECONDS

weeks before Rosetta is expected to make its own landing on the comet, ending the successful twoyear mission. Philae’s rough location has been known since June 2015, when the lander unexpectedly woke up

ONE of the greatest space exploration stories of recent times finally has a happy ending. The Philae lander, thought lost after its botched touchdown on comet 67P/ChuryumovGerasimenko in November 2014, “Pinpointing the lander’s site will help mission has been found. scientists understand Images taken by the orbiting Rosetta spacecraft on 2 September the data it sent back” reveal that its marooned companion is wedged against a and briefly resumed radio contact. dark cliff on the comet’s surface, Pinpointing its landing site will just as mission managers at the give mission scientists the European Space Agency had context needed to fully suspected. The find comes just understand the data it sent back.

US bee massacre

Gorillas wane as pandas bounce

THOMAS MARENT / MINDEN PICTURES

MILLIONS of bees were wiped out EASTERN gorillas are sliding towards extinction, conservationists warn. in South Carolina on 28 August by The plight of these primates is a pesticide sprayed with the aim highlighted in the latest global Red of killing mosquitoes that can List of Threatened Species, which transmit the Zika virus. reclassifies their status from In response to four local cases endangered to critically endangered, of Zika, Dorchester County used a plane to spray Naled, a neurotoxin just one step from being declared extinct in the wild. that kills adult mosquitoes and Found in East Africa, the gorillas other insects while they are are illegally hunted for bushmeat and airborne. a commercial trade in live infants. In But the four infected people all caught the virus before arriving in the past 20 years, populations have South Carolina: no one in the state nosedived by more than 70 per cent. Their new status means that four has yet acquired Zika locally. And out of the world’s six great apes – the bees could have been spared humans’ nearest relatives – are now by spraying when mosquitoes are critically endangered, according to active but bees are in their hives. the International Union for “We can target them effectively Conservation of Nature (IUCN), with aerial spraying starting just before sunset and for the following 30 to 60 minutes,” says Mark Latham, director of Manatee County Mosquito Control in Palmetto, Florida, an area with commercial beekeepers. “Bees are usually back home in their hives well before sunset.” Naled should really be “a last resort, when the disease is established”, says Aimee Code, the pesticide programme director of the Xerces Society for Invertebrate Conservation. The spraying “feels like it was more fear based”, she says, and probably also killed wild –Laid low by hunting– bees and other pollinators.

which publishes the Red List. Illegal hunting has also affected plains zebras, with numbers declining by almost a quarter in the past 14 years. The Red List now considers them “near threatened”. But there is better news elsewhere. One of conservation’s flagship species, the giant panda, has changed from endangered to vulnerable. This is as a result of Chinese government efforts to conserve pandas, with effective measures to protect and restore forests, the IUCN says. However, it also warns that climate change is predicted to wipe out more than a third of the panda’s bamboo habitat, which could reverse the gains made.

SpaceX explosion A SpaceX rocket blew up on the launch pad as it was being fuelled on 1 September. Eyewitnesses at the Cape Canaveral Air Force Station in Florida reported multiple explosions, dark smoke and shaking buildings. The explosion seems to have started in the rocket’s oxygen tank. The Falcon 9 rocket was due to put an Israeli communications satellite in orbit, which Facebook intended to use to provide internet access in remote areas.

No malaria in Sri Lanka Sri Lanka has been declared free of malaria, a “truly remarkable” feat, according to the World Health Organization. No locally transmitted cases have been recorded there in over three years, thanks in part to treatment offered at mobile clinics.

Warming’s impact felt The warming of the world’s oceans is affecting fish stocks, spreading diseases and cutting crop yields, says a new report by the International Union for Conservation of Nature. Many processes are involved: the Vibrio bacteria that cause cholera thrive in warmer water, for example.

Climate agreement win The world’s biggest emitters of greenhouse gases, the US and China, have said they will formally ratify the Paris climate agreement. The pact needs 55 countries, representing 55 per cent of global emissions, to ratify it before it comes into force. The US and Chinese action brings the tally to 26 countries and 39 per cent of emissions.

Not big on exercise People who weigh less than 2.5 kilograms at birth are less likely to do well in school sports and to exercise regularly as adults, according to a study of 3000 people (Medicine & Science in Sports & Exercise, doi.org/ bqbv). It could be that underweight babies end up with lower strength and poorer motor skills.

10 September 2016 | NewScientist | 5

THIS WEEK After her body has been cleared of cancer, thousands of stromal cells – which help the follicles produce eggs – would be removed from the woman’s remaining

JGI/DANIEL GRILL/GETTY

“It may be used by women who want to delay having babies or postpone the menopause” ovary and placed inside the clot, which would then be transplanted into her body. The method could benefit other women, too. “When fully developed, this technology may be used in women who want to –Hope for many– delay having babies for social reasons, or who want to postpone the menopause,” says Claus Andersen at the University Hospital of Copenhagen, Denmark. Follicles produce hormones Making a synthetic home for a woman’s egg-producing follicles could like oestrogen, so artificial ovaries boost fertility after chemotherapy, finds Andy Coghlan could be used to delay or alleviate the symptoms of the menopause. A SYNTHETIC ovary that could protein that normally forms the women receive transplants “The main goal here isn’t ‘youth’, help both older women and those scaffolding of blood clots. of frozen ovarian tissue, says but to avoid the health problems with endometriosis conceive is a When the team implanted two Amorim. “That procedure has that are usually linked to step closer. Initially intended for of these synthetic ovaries into already resulted in more than menopause, like osteoporosis and women who have undergone each of the abdominal cavities of 60 live births since 2004, so our heart disease,” says Amorim. cancer treatment, the prototype is eight mice, more than a fifth of results with the artificial ovary It could also help women with the first artificial organ capable of the follicles were still alive a week look very encouraging.” endometriosis conceive. This keeping human egg-producing later (Reproductive BioMedicine Her plan for women having condition affects 10 per cent of follicles alive outside a woman’s Online, doi.org/bqbr). chemotherapy would be to women, and involves uterus cells body. It may also be used to delay This is around the same remove one ovary, and place moving and forming cysts and the onset of the menopause. proportion that survives when follicles from it in a fibrin clot. lesions throughout a woman’s Women can become infertile abdominal cavity. Surgery to after cancer treatment as the alleviate the condition can MAKING NEW EGGS ovaries and the egg-making prompt a woman to lose many of An artificial ovary can help fertility able to get the whole process follicles they contain are her follicles, but an artificial ovary if you have viable eggs – but what if in-vitro,” says Evelyn Telfer at the vulnerable to chemotherapy, could later reintroduce eggyou don’t have many? Researchers University of Edinburgh, UK. “They’ve especially for leukaemias, brain making cells to boost fertility. in Japan have produced 101 healthy worked out exactly the factors cancers and lymphomas. But there is still work to do mouse pups from eggs generated needed at each of the stages.” Removing and freezing ovarian before the technique can be tried entirely in the lab from stem cells. The egg generation process took tissue beforehand to reimplant in people. First, the team will Yuji Hirao at the Institute of 33 days, says Hirao, and may offer after treatment can help women study artificial ovaries in mice Livestock and Grassland Science in a new way to help infertile women. conceive, but there is a risk to see if they make healthy eggs. Tsukuba and his team replicated the “More than 99.9 per cent of egg that this tissue will reintroduce “The progress of this work is conditions of an ovary in a dish to precursor cells die in the human hidden cancer cells. fascinating, but it is still an open encourage primordial germ cells to ovary, but would the same happen Making a new ovary could solve question whether it will be generate fully grown mouse oocytes. in a dish under our optimum growth this. Christiani Amorim at the successful,” says Michael von When the mice born from the eggs conditions?” he says. “If we could Catholic University of Louvain Wolff of the Women’s University mated, they were able to produce reveal why and how those 99.9 per (UCL) in Belgium and her team Hospital in Bern, Switzerland. We offspring (PNAS, doi.org/bqbs). cent die, we could help sustain the have managed to encapsulate don’t know if an artificial ovary “It’s the first time anyone’s been fertility of women.” donated human follicles inside would be as effective as ovary bundles of fibrin, the tough freezing, he says. ■

Artificial ovary in sight

6 | NewScientist | 10 September 2016

In this section ■ Nuclear bunker ant colony, page 8 ■ The Great Green Wall, page 16 ■ Putting your data to work for you, page 22

Create a better universe to make life more likely

Arctic whale populations may be soaring IT’S boom time for large whales in the Arctic – an unexpected benefit of the unprecedented sea ice reduction seen in the region over the past 30 years. Sue Moore at the National Oceanic and Atmospheric Administration in Seattle has analysed 30 years of whale survey information gathered in the Chukchi Sea – which separates Russia and Alaska – and the

“The natural stepping stone towards bigger elements is not present,” says Adams. That’s no way to build a cosmos – yet strangely, here we are. In the 1950s, astronomer Fred Hoyle figured out a solution. He argued that the abundance of carbon in the universe must be the result of a coincidence between the energy levels of alpha particles and carbon-12. Hoyle said that because the energy of three alpha particles creates carbon-12 with more energy than it needs to be stable,

NASA, ESA, AND THE HUBBLE HERITAGE TEAM (STSCI/AURA)

YOUR existence depends on an improbable threesome: a delicate reaction within stars called the triple-alpha process, which creates carbon. This is often used to support the idea of the multiverse. But stars in other universes might have alternative ways of producing carbon, giving life as we know it a greater chance in multiple universes. At least, that’s the view of Fred Adams at the University of Michigan in Ann Arbor and his colleague Evan Grohs. The triple-alpha process gets its name from the three helium nuclei involved, also known as alpha particles. When the universe formed, it mostly consisted of hydrogen and helium, the simplest elements in the periodic table. Heavier elements were forged by the first stars, which fused the lighter nuclei together. There’s just one problem with this tidy model. Fuse two alpha particles and you end up with a nucleus of four protons and four neutrons – namely beryllium-8. But this isotope is highly unstable and falls apart into two alpha particles within a fraction of a second. That means there isn’t much of it in our universe.

this extra energy must be equal to an excited state of carbon-12, allowing it to decay to its ground state and remain stable. This socalled “resonance” between the energy values makes it possible to form carbon by fusing three alpha particles together. Experiments later proved him right, but vary the energy levels slightly and no carbon is produced at all. Hoyle and others argued that this means our universe must have been fine-tuned for life. That resonance could have occurred at a range of energies, and the fact that it just happened to take place at the crucial point for us to exist makes us astonishingly lucky. The odds of this happening at

random are very low, and some argue that the only way to explain it is if our universe is just one of many in a multiverse. In that case, each universe could have slightly different values for the fundamental constants of physics. Life would arise only in suitable universes, meaning we shouldn’t be surprised to find ourselves in one of these. But now Adams and Grohs argue that if other universes have different fundamental constants anyway, it’s possible to create a universe in which beryllium-8 is stable, thus making it easy to form carbon and the heavier elements. For this to happen, a change in the binding energy of beryllium-8 of less than 0.1 megaelectronvolts would be required – something that should be possible by slightly altering the strength of the strong force, which is responsible for holding nuclei together. Simulating how stars might burn in such a universe, they found that the stable beryllium-8 would create an abundance of carbon, meaning life as we know it could potentially arise. These alternate universes would arguably be more logical, he says, with stars steadily building elements along the periodic table without having to resort to the triple-alpha process. “In some sense, we’ve designed a better universe,” says Adams.

–Life, but more logical than ours– Jacob Aron ■

surrounding area. She realised that three species of plankton-eating baleen whales – humpback, fin and minke – are now routinely spotted in the region, even though surveys in the 1980s never encountered these species there. The population of bowheads – a baleen whale native to the Arctic – may also be thriving, according to Moore’s analysis (Biology Letters, DOI: 10.1098/rsbl.2016.0251). This rise in whale sightings coincides with melting sea ice. “Millions of square miles of sea ice has been lost in the past decade,”

says Marc Macias-Fauria at the University of Oxford. The lack of ice leads to extraordinarily favourable growing conditions for zooplankton – which is a good thing for the baleen whales that eat them, says Patrick Miller at the University of St Andrews in the UK. More light can penetrate into the surface water of ice-free oceans, fuelling blooms of phytoplankton and

“A lack of ice leads to favourable conditions for zooplankton – great for the whales that eat them”

the zooplankton that graze on them. Nutrient levels also increase. “Wind driven across the now open sea surface causes water to mix,” says Miller. “This brings nutrients up from depth.” Some believe the Arctic has entered a “new normal” in which there is permanently less sea ice. But this might ultimately create more problems for the whales. This is because the ice-free waters are attracting more human attention – and the noise from our marine activities may have a detrimental impact on Arctic whale populations in the longer term. Laura Hampton ■ 10 September 2016 | NewScientist | 7

THIS WEEK

Secrets of an ageresistant memory Rogalski. “They don’t all have a high IQ, and they aren’t all doctors and lawyers. Their health history is very variable, but cognitively, they’re doing much better than their peers.” A few years ago, though, the team did find that a brain region

AS WE get older we get wiser, or so they say. Most other functions go downhill though, particularly memory – unless you happen to be a “superager”, one of a rare group who retain a good memory. To qualify as a superager, someone must be over the age of 80 but perform as well as 55-yearolds in memory tests. When asked to recall a list of 15 words 15 minutes after hearing them, the average 80-year-old remembers about five, while superagers can manage around nine. Emily Rogalski and her colleagues at Northwestern University in Chicago are trying to figure out how they do this. By screening more than 1000 people who thought they had an exceptional memory, the team recruited 62 superagers to study. So far, the team have found no obvious lifestyle clues. “They don’t all have pristine diets or exercise regimens – some of them drink, and some have been smoking for many years,” says

Nuclear bunker ants build a zombie colony KEEP calm and carry on building. That’s the motto of 100,000 or so wood ants stranded without food in a nuclear bunker until they starve. Wood ants (Formica polyctena) typically build a cosy mound nest on the forest floor. They seek out the sugary secretions of aphids living on trees and supplement their diet with insects. Now, scientists have studied a population of wood ants that has sustained itself for years without food and light inside a cold bunker. 8 | NewScientist | 10 September 2016

AP PHOTO/M. SPENCER GREEN

Jessica Hamzelou

The ant population was discovered in 2013 by a group of volunteers counting bats overwintering in the bunker, which is part of an abandoned Soviet nuclear base near Templewo in western Poland. Later, Wojciech Czechowski at the Museum and Institute of Zoology in Warsaw and his colleagues studied the ants more closely. The nest covers most of the 3 metres by 1 metre terracotta floor of a chamber. Above it is a ventilation pipe that seems to provide an endless supply of doomed new recruits. These ants originate from another nest, which sits on the forest floor directly on top of the ventilation pipe outlet. They can fall in because the

called the anterior cingulate cortex, involved in attention, is thicker in superagers than in others of the same age. “If superagers have this younglooking brain, how do they maintain it?” says Rogalski. To find out, her team scanned the brains of 25 superagers aged between 80 and 101, and 15 people of a similar age with average memories. After 18 months, they repeated the scans. From the age of 40, our brains shrink at a rate of 5 per cent per

decade. The process seems to accelerate after the age of 70 and affects the entire brain. But superagers’ brains shrank by an average of only 0.8 per cent over the 18-month period, compared with 2 per cent in other volunteers, Rogalski told the International Conference on Memory in Budapest, Hungary, in July. “It’s quite remarkable,” says Boris Konrad of the Donders Institute for Brain, Cognition and Behaviour in Nijmegen, the Netherlands. The finding suggests that superagers’ brains don’t show any signs of being special until later in life. This fits with what the superagers say themselves. “They don’t report exceptional memory at school, and they don’t have a greater educational attainment,” says Rogalski. The team are now looking for more clues in the superagers’ genes and personality traits. The superagers are generally an enthusiastic bunch. One man was so pleased to find out he was one that he now wears a “superager” cape his friend made him. “A few years ago they all met each other,” says Rogalski. “One said he was looking for a new spouse, and that a fellow superager might make a –Youthful in spirit, and in brain– good one.” ■

metal cap over the pipe has rusted. It’s a one-way journey. The ants can scale the bunker’s 2.3-metre-high walls, but Czechowski’s team found that – for some reason – the ants never walk across the bunker ceiling and so are unable to reach the ventilation pipe to make it back home. Instead, they gathered together and did what ants do, says Terry McGlynn, an entomologist at California State University in Dominguez Hills. “They built a nest and eked out an existence.”

“It’s fascinating that such a huge, non-productive nest exists on its own, built only by trapped ants”

Czechowski and his colleagues have yet to discover any food source that could sustain the ants. It looks like they are doomed to starve to death in pitch-blackness: an estimated 2 million ant corpses carpet the bunker floor in a layer a few centimetres thick (Journal of Hymenoptera Research, doi.org/bp9d). The “colony” is queenless and comprises a strange, nest-like structure that the population of worker ants has instinctively built. “This is kind of fascinating that such a huge, non-productive nest could exist on its own, built solely by the ants that got trapped in the bunker,” McGlynn says. Richa Malhotra ■

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THIS WEEK Pollution fills your brain with metal particles

It’s the taste we’ve been missing Jessica Hamzelou

assumption was that we detect starch by tasting those molecules. Lim’s team tested this by giving volunteers a range of different carbohydrate solutions. They found they were able to detect a starch-like taste from carbohydrate chains of various lengths. “They called the taste ‘starchy’,” says Lim. “Asians would say it was ricelike, while Caucasians described it as bread-like or pasta-like. It’s like eating flour.” The volunteers could still make out this floury flavour when they

A CARB craving can be hard to resist, but why? The explanation might lie in new evidence that carbohydrate-rich foods may have a unique taste. We used to think that our tongues registered just four primary tastes: salty, sweet, sour and bitter. Umami, the savoury taste often associated with monosodium glutamate, joined the list in 2009. However, this misses out a key component of our diet, says Juyun Lim at Oregon State University in “Sugar tastes great in the short term, but if offered Corvallis. “Every culture has a chocolate and bread, you’d major source of complex choose bread as a staple” carbohydrate. The idea that we can’t taste what we’re eating doesn’t make sense,” she says. were given a compound that Complex carbohydrates such blocks the tongue’s sweet as starch, which are made from receptors. This suggests we can chains of sugar molecules, are an detect carbohydrates before they important source of energy. But have been completely broken food scientists have tended to down into sugar molecules overlook the possibility that we (Chemical Senses, doi.org/bpz6). might be able to specifically taste This is the first evidence that we them, says Lim. Because enzymes can taste starch as a flavour in its in our saliva break starch down own right, says Lim. into simple sugars, the Michael Tordoff at Monell 10 | NewScientist | 10 September 2016

TRAFFIC fumes go to your head. Tiny specks of metal in car exhaust gases seem to fly up our noses and travel into our brains, where they may contribute to Alzheimer’s disease. Barbara Maher of Lancaster University in the UK and her team looked at the brains of 37 people who had lived in Manchester in the UK or Mexico City. All contained millions of iron oxide nanoparticles per gram of brain tissue (PNAS, DOI: 10.1073/ –Yum… starch– pnas.1605941113) A closer look at six brains found that round particles outnumbered angular Chemical Senses Center in crystals 100 to one. Crystal forms of Philadelphia says the evidence is iron oxide are more likely to have a impressive. “It will surprise a lot of people,” he says. “Many people natural source, whereas round particles normally come from melting think there are only five tastes, iron at high temperatures. but a bunch of us think there Maher says the particles’ round might be others.” shape is compelling evidence that Researchers are already they come from pollution. “There is investigating other potential tastes, such as flavours associated iron as impurities in fuel, and there is iron in a car engine block,” she says. with carbonated drinks, amino “If you walk down the street you’ll be acids – the building blocks of breathing them in – how could they proteins – and blood, which has a metallic quality. “We are moving not get into your system?” These nanoparticles are less than away from the idea of five 200 nanometres in diameter, so may primary tastes,” says Lim. be moving from the air into the nerve But before any new flavours endings in our noses, and from there can be enshrined as primary to the brain, says Maher’s team. tastes, they must meet a strict Previous work on cells grown in the list of criteria. Tastes need to be lab has suggested that iron oxide is recognisable, have their own set present in the protein plaques of tongue receptors, and trigger some kind of beneficial response. thought to have a role in Alzheimer’s disease, and that it generates reactive Starch doesn’t tick all of compounds called free radicals, which these boxes: no starch-specific can kill nerve cells. Population studies receptors on the tongue have have found that people who live been identified yet. But another nearer busy roads have a higher risk criterion is that a flavour must be of mental impairment in old age. useful to us. There’s a strong case But these kinds of studies have to be made for starch here, which is well worth detecting as it is both also found that our risk of getting Alzheimer’s by a particular age is high in energy and slower to falling, so if pollution is contributing release it than sugar. to the disease, it doesn’t seem to be “I believe that’s why people making it more common. Even so, prefer complex carbs,” says Lim. reducing air pollution might cut our “Sugar tastes great in the short risk of Alzheimer’s, says Jo Anne term, but if you’re offered chocolate and bread, you’d choose Shatkin, at US environmental health firm Vireo Advisors. Clare Wilson ■ bread as a daily staple.” ■

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IN BRIEF Vibrant clouds paint exoplanet skies

Long-term forecast predicts stronger typhoons BATTEN down the hatches. Typhoons pummelling the coastlines of east and South-East Asia have become more destructive in recent decades, and are likely to worsen further because of climate change. A new study reveals that, on average, typhoons hitting the region have grown in intensity by 14 per cent compared with 40 years ago, with the average wind speed increasing by 7 metres per second. “That’s a huge difference,” says Wei Mei at the University of North Carolina at Chapel Hill, who carried out the study with Shang-Ping Xie at the University of

California at San Diego. It equates to an increase in destructiveness of 50 per cent, says Mei. The intensification was restricted mainly to typhoons that reached land, perhaps because seawater closer to land is warming more rapidly and can feed more energy into the storm. Sea surface temperatures are projected to rise fastest above 20 degrees latitude — roughly, from Taiwan northwards — so typhoons here are likely to intensify most in the future (Nature Geoscience, doi.org/bp9b). “The results leave little doubt that there are more high-intensity events affecting South-East Asia and China,” says Kerry Emanuel at the Massachusetts Institute of Technology – although the driving factor might be regional phenomena rather than global warming.

Manic episodes linked to childhood INFLAMMATION as a child may predict a higher risk of manic behaviour during adulthood. Hypomania involves spells of hyperactivity and is often a symptom of mood disorders such as bipolar disorder and some kinds of psychosis. People experiencing hypomania may take more risks, feel more confident and become impatient with others.

Earlier studies suggested a link between inflammation and mood disorders, prompting Joseph Hayes at University College London and his team to see if inflammation as a child leads to mental health problems later. Analysing data from more than 1700 people, his team identified a significant link between high levels of an inflammationstimulating chemical at age 9,

and experiencing features of hypomania at age 22 (Psychological Medicine, doi.org/ bp6b). Hayes’s team says it is unclear how inflammation could induce hypomanic symptoms, but the chemical, called IL-6, is also known to affect the brain and cause anxiety. The team suggests that targeting inflammatory pathways may help treat conditions such as bipolar disorder.

IMAGINE a world where the skies glow traffic-cone orange and indigo. That’s the view from hot Jupiters, faraway gas giants that lie much closer to their stars than Mercury sits to our sun. We have seen evidence of clouds in their atmospheres, but the details are still, well, cloudy. So Vivien Parmentier at the University of Arizona, Tucson, and colleagues modelled the planets’ temperature variations, based on factors like distance from a star and wind circulation. Different temperatures lead to different clouds because of the way various elements condense (Astrophysical Journal, doi.org/bp8b). Looking down from a spaceship, a cloudless sky would appear deep blue because of the presence of sodium, which absorbs red light. Hotter regions would glow like burning coal and reddish-orange manganese sulphide clouds would cloak cooler areas.

Fluorescent dye makes blood a laser BLOOD lasers could help doctors hunt down tumours. Lasers need an initial light source, a reflective cavity, and a light-amplifying material. Xudong Fan at the University of Michigan, Ann Arbor, and his colleagues found that blood mixed with a fluorescent dye did the trick. The dye is normally used for medical imaging, but the team turned the mixture into a laser medium by putting it in a cavity in the lab, and shining a regular laser at it (Optica, doi.org/bp8c). Tissues with plenty of blood vessels, such as tumours, should glow more brightly because the dye builds up there. Doctors looking for tumours could inject the dye, shine an ordinary laser at the skin and check for a glow. 10 September 2016 | NewScientist | 13

IN BRIEF

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SUPERFAST evolution could save Tasmanian devils from extinction. The marsupial seems to have developed resistance to a deadly cancer in just a few generations. Devil facial tumour disease is a transmissible and usually lethal cancer that was first observed in Tasmanian devils in 1996. It is passed between animals when they bite one another, and has wiped out 80 per cent of the species. This prompted extinction fears, but some populations now seem to be doing better than computer models of the disease predict. To understand why, Menna Jones at the University of Tasmania, Australia, and her colleagues analysed the genomes of almost 300 devils. Populations affected by the disease differed from pre-disease ones in two regions of the genome, both with known links to cancer and immunity. This hints that genetic resistance to the cancer has spread through devil populations, which might explain why more animals than expected are now surviving. Given what is known about how devils reproduce, the team estimates that resistance spread through the population over just four to six generations. “It has happened a lot faster than we expected,” says Jones (Nature Communications, doi.org/bp5z).

14 | NewScientist | 10 September 2016

Tiny ‘fossils’ may be sign of life from 3.7 billion years ago THEIR small size belies their importance. Structures discovered in 3.7-billion-year-old rocks in Greenland seem to be evidence of microbes living in a shallow sea on early Earth. The structures, all no more than a few centimetres tall, look like stromatolites. These are layered mounds that were – and still are – formed by photosynthetic microbes living in water. The structures are about 220 million years older than any previously found fossils.

They come from a region of south-west Greenland called the Isua supracrustal belt where the ancient rock has not been exposed to the extreme temperatures and pressures that normally destroy very old fossils (Nature, doi.org/bp79). “This is one of the extremely few places where this kind of feature could still be preserved in the rock record,” says Allen Nutman at the University of Wollongong in Australia, who led the team that found the fossils. However, doubts remain. The

main problem, says William Schopf at University of California, Los Angeles, is that the Isua rocks contain no fossil remains of microbes. “To seal the case, you’d really like to have the microorganisms preserved.” If the rocky formations are stromatolites, the microbes that created them were probably part of a larger community that had already evolved on Earth, says Nutman. “What we have in Isua is just a tiny sample of any life that may have been around at that time,” he says. MICHAEL PITTS / NATUREPL

Evolution steps in to save the devils

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Prozac compound may thin bones ANTIDEPRESSANTS may be bad for your bones. People who take some selective serotonin reuptake inhibitors have been found to have a higher risk of fractures, but it wasn’t clear whether this was due to the drug or their depression. Now Patricia Ducy at Columbia University, New York, and her team have found that giving mice fluoxetine – the active ingredient in Prozac – for six weeks causes them to lose bone mass. The team identified a two-stage process by measuring bones, blood and gene activity. During the first three weeks, bones grew stronger as the fluoxetine impaired osteoclasts, cells that usually deplete bone tissue. But by six weeks, the higher levels of serotonin prompted by the drug disrupted the ability of the hypothalamus region of the brain to promote bone growth (Nature Medicine, DOI: 10.1038/nm.4166). Ducy says this two-phase pattern is also seen in people. In the short term, those who take fluoxetine are less likely to break a bone, but the risk of depletion and fractures rises when they have been taking the drug for a year or more.

Brain bots copy bats to find cancer DELVING deep inside the human brain to look for damage is no easy task. Tiny robots crawling through it could help. It’s a tantalising idea, but one problem is how to direct such nanobots on their travels. Panagiotis Katrakazas at the National Technical University of Athens, Greece, and his team have turned to algorithms that describe swarming behaviour in bats. These are based on the acoustic signals that bats emit to navigate and find prey, and the team hopes that these algorithms could be used to direct investigatory nanobots

through the brain to look for damage or cancer. Control signals could be emitted, for example, by a cap placed on the head. A computer simulation showed that with a bat-based approach, just four bots would be needed to find a small tumour within a matter of minutes, Katrakazas told the IEEE Engineering in Medicine and Biology Society meeting in Orlando, Florida, last month. Katrakazas hopes to build a system based on this approach and begin trialling it in people within a few years.

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ANALYSIS DESERTIFICATION

–From saplings to walls-

Green and desert land Plans to hold back the Sahara with a wall of trees across Africa are audacious but misguided, says Fred Pearce IT IS terraforming on a grand scale. A sinuous line of trees has started to spring up across the hottest, driest and widest part of Africa. Once finished, the band of green against gold will stretch from the Atlantic coast of Senegal, across the southern fringe of the Sahara desert to the Red Sea – and be visible from space. The purpose of this Great Green Wall? To hold back the advancing sands of the Sahara in the name of fighting climate change. Formally inaugurated in May, it is a grand project of the African Union (AU), with 11 nations signed up. Senegal has taken the lead and 16 | NewScientist | 10 September 2016

last year its president Macky Sall promised for the project, which announced that it had already is being masterminded by forest planted 12 million trees, mostly scientists working for the AU. native acacias. The final wall, The World Bank, the European set to be 15 kilometres wide and Union and private investors are almost 8000 kilometres long, will all piling in. number more than a billion trees. The wall’s backers say it will halt And yet questions abound. the desert’s advances, cool the air Will it work? What part of the with its shade, block sand storms, “desertification” process is it provide shelter for livestock, intended to prevent? Is advancing fertilise soils and protect water sand the real problem? Come to supplies. By bringing rural that, what’s wrong with deserts prosperity, it could also counter anyway? Maybe we should be saving deserts – and their unique “The final wall will be 15 kilometres wide and 8000 flora and fauna – rather than kilometres long, with more fighting them. than a billion trees” Some $4 billion has so far been

the rise of Islamic militants such as Boko Haram. Abdou Maisharou, director of Niger’s National Great Green Wall Agency, has said it would “deter young people from leaving their lands [and so] combat terrorism”. Wildlife could also benefit. Elvis Paul Tangem, who coordinates the project for the AU, claimed recently that antelope, hares and birds are returning to newly forested areas in Senegal after a 50 year absence. The Great Green Wall has strong echoes of China’s recent efforts to create its own belt of an estimated 100 billion trees, a project that

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shows some signs of improving vegetation and reducing dust storms. But few desert specialists believe it will work in the Sahara. “Technically it makes no sense,” says Chris Reij of the World Resources Institute, a US think tank. “We don’t need a Great Green Wall. It solves nothing. We need green landscapes instead.” Part of the problem is that many believe the diagnosis is wrong. The science behind an advancing Sahara is hotly contested: many researchers say the whole idea – which has been a given of environmental debate since the 1970s – is a myth.

Wrong diagnosis “Localised, even severe, land degradation certainly exists in the region,” says UK-based geographer Mike Mortimore, who recently co-authored the book The End of Desertification? It may result from changing climatic conditions, overgrazing, clearing vegetation for farming, or dams and water diversions that deprive low-lying areas along rivers of their natural floods. But these short-term local changes, usually assessed from aerial surveys, are being misread as part of a widespread, long-term trend, he says. “There is no evidence of a catastrophic regional environmental crisis.” In reality, deserts advance and retreat regularly, often as a result of routine climatic variability. During droughts in the 1970s and 80s, the Sahara did in some places move south. At the time livestock herders were blamed for creating irreversible advances by overgrazing their animals on the fringes of the Sahara. But since the 1990s, the desert has retreated in many places, often as rains have improved. Mortimore says it is wrong to blame overgrazing, as the UN Environment Programme, which once demonised the practice, now says pastoralism is a very

sustainable food system. Instead, poor water management is behind the continued spread of deserts in some regions, says Jane Madgwick, director of the Dutch-based NGO Wetlands International – and the Great Green Wall isn’t the cure. Take Lake Chad, on the border between Niger, Nigeria, Chad and Cameroon, which is only a tenth the size it was a few decades ago. The wall is planned to pass through the heart of the huge basin of rivers that drain into the lake. But irrigation dams, not deserts, are to blame for its decline, says Madgwick. They have emptied the lake, dried out downstream pastures and left tens of thousands of herders destitute, she says. Planting trees won’t reverse the lake’s fortunes. In any case, the idea of seeing deserts as an ecological disease to be fought is foolhardy. Deserts are natural ecosystems, home to numerous species that have made it their own, many of which are endangered. Traditional nomadic societies found ways to live in such environments, through hunting and herding animals. Modern farming methods fail without massive imports of irrigation water, which may

Green against gold The Great Green Wall project plans to plant a line of trees almost 8000 kilometres across Africa, with the aim of holding back the Saharan sands

SAHARA MA AURITANIA

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NIGER

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CHAD

ERITREA ER SUDAN DAN DJIBOUTI

NIGERIA ETHIOPIA SENEGAL

BURKINA FASO

create new deserts elsewhere. Niger to Mali, Burkina Faso and Reij points to farmers across the beyond. Certainly far more trees region who have found their own have emerged in the landscape way of reviving their arid lands, thanks to these farmers than often by abandoning the advice from the Great Green Wall. given to them by governments The wall project is already to cut down native trees and “We don’t need a Great nurturing them instead (see Green Wall. It solves “View from the ground”, below). nothing. We need green The results have been spectacular, says Reij. His research landscapes instead” shows that trees growing amid crops retain water on the land, working with local people. Moctar improve soils through dropping Sacande, a forest ecologist at leaf litter and stave off drought. London’s Royal Botanic Gardens The practice is spreading, from in Kew, is masterminding a programme in Mali, Burkina Faso and Niger as part of the Great VIEW FROM THE GROUND Green Wall to consult villagers “A decade ago this land was government agricultural advisers about native seeds for use in dismissed as lost to the desert,” to uproot trees on their fields and growing the wall. They will collect says ecologist Mamadou Diakite. But chop out any new growth, they the seeds locally, propagate them now he is smiling beneath the shade have nurtured them instead. in nurseries and pay villagers to of a tree, one of hundreds growing plant them. “We start by vigorously around us on what was BRINGING IT BACK consulting communities,”he says. once parched land, abandoned by Begun in neighbouring Niger more But Reij and others believe local millet farmers in a remote than a decade ago, the practice, the farmer-led approach of region of Mali near the ancient city dubbed Farmer-Managed Natural encouraging existing trees could of Djenné. Regeneration, is now spreading. It be the basis for the recovery of Though the Mali government has been supported by NGOs such ecosystems around the Sahara supports the Great Green Wall project as Diakite’s Mali-based organisation, that would benefit farmers, (see main story), these trees aren’t Sahel Eco. cattle herders and wildlife alike. the result of an official planting “It was slow to take off, but now Perhaps, suggests Reij, the programme. Instead, local farmers they all want to do it,” he says. “The strategy of the Great Green Wall have been encouraging the growth land is coming back into production. could be changed to follow the of trees on land at the edge of the Farmers use the wood for firewood farmers’ lead. The ultimate irony desert. Rather than following and the leaves provide fodder for would be for a green landscape to long-standing advice from their animals and fertilise the soils.” emerge without a single further tree being planted. ■ 10 September 2016 | NewScientist | 17

COMMENT

It’ll never fly US officials keen to use GM mosquitoes to fight Zika may have to bow to ill-founded public fears, says Jamais Cascio WITH Zika virus now spreading in Miami, you would think citizens of the nearby Florida Keys would welcome all efforts to control the insects that carry it. Yet a battle is building between officials and the public. At issue is a trial release of sterile males of the Aedes aegypti mosquito – the primary carrier of Zika – on Key Haven. Known as the sterile insect technique, this is a proven way to stem outbreaks of disease. Females that mate with these males produce no offspring, so the population drops. Tsetse and Mediterranean fruit flies have already been targeted. But making male mosquitoes sterile by exposing them to gamma radiation – the usual method – is tricky. They tend to be more vulnerable to its effects than other insects, becoming sterile but so weakened they can’t successfully compete for mates.

There is an alternative. Get them to make excessive amounts of a protein that causes offspring to die soon after birth. This seems an ideal solution – one that the US Department of Health and Human Services has preliminarily declared safe. But the technique has two words at its core that are sparking public protest: “genetic modification”. A recent study highlighted the disquiet. It found that 58 per cent of Key Haven residents “opposed” or “strongly opposed” the release of such mosquitoes. The language used in the survey may have had an impact. Questions emphasised genetic modification over the broadly familiar sterilisation aspect. One wonders what a survey would find if, rather than talking about the sterile insect technique, it asked about unleashing “gamma-irradiated mosquitoes”.

Only a ban will do Cheap trans fats in food are costing lives and our failure to act is shameful, says Luke Allen THE absence of a global ban on artificial trans fats in food is a looming health scandal. Scientists have known about the dangers of these fats for a quarter of a century, yet millions of people worldwide still consume dangerously high levels. Found in some cakes, biscuits, margarines, pastries, fried and 18 | NewScientist | 10 September 2016

fast foods, they are a cheap and tasty ingredient but offer no nutritional advantage over other fats. On the contrary, they raise the risk of heart attack and stroke. Healthier alternatives can take their place, although they tend to cost more. Denmark led the way with a trans fat ban in 2003. More than

20 nations followed suit, but others, including the US, Australia and Canada, still allow trans fats provided the labelling is clear. This only protects those who take the time to figure out food labels and doesn’t cover non-packaged foods like restaurant meals. Other countries have relied on the food industry to act voluntarily. This has worked surprisingly well in the UK and the Netherlands, but it is still possible to exceed safe limits.

“The complete elimination of artificial trans fats from the food supply would save millions of lives”

The US has now decided on a total ban by 2018, a move that will prevent 20,000 heart attacks and 7000 deaths every year. The European Commission has also recommended a ban. Momentum is growing for global legislation, and even companies such as Mars and Nestlé have lobbied for action. The complete elimination of trans fats would save millions of lives, save on health spending, reduce global health inequalities, and expedite investment in healthier alternative oils, creating economies of scale that drive down their cost. The World Health Organization is the best bet for brokering a ban.

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Jamais Cascio is a distinguished fellow at the Institute for the Future in Palo Alto, California

It should escalate the matter at its global health promotion meeting in Shanghai, China, in November. Researchers are already calling for a global ban. Individual nations could simply incorporate such a ban into domestic law, a model that worked brilliantly with tobacco. Continued inaction is now an embarrassment: we are allowing industry cost considerations to trump lives. Denmark shouldn’t be the only place where the Danish pastries are safe to eat. ■ Luke Allen is a doctor in the UK and a global health analyst for the WHO at the University of Oxford

INSIGHT First contact

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The trial’s fate is complicated now that three of five Florida Keys Mosquito Control District members have said they will abide by the result of November’s non-binding public referendum on the topic. Florida officials face a catch-22 if they press ahead after a no vote. They would be using the most effective control method with the best hope of heading off a Zika outbreak, better than pesticides and draining standing water. But the public and media would be ready to pounce and see any accidents or mistakes, even tangentially related to the release, as catastrophic. Importantly, mistrust and resentment towards science-based policy would grow. It’s rarely good to let irrational fears overcome science. But releasing modified mosquitoes over the objections of locals would risk harming the ability to pursue other science-supported goals. With the threat of climate disruption growing, the difficult conclusion is that we can’t afford to let a dispute about mosquito control erode our ability to respond to far greater problems. The Florida officials must go with whatever the people decide. ■

–Never going to happen–

Whymysteriousspace signalsareneveraliens Jacob Aron

low, a universe 93 billion light years wide provides ample rolls of the dice to get things started. And yet, its vastness also prevents us from making contact. Seth Shostak at the SETI Institute in Mountain View, California, calculated that if the signal had been real, aliens at HD 164595 would have needed to consume an entire sun to provide enough energy for it to reach us, assuming they beamed it in all directions. If the message was specifically directed at us, that energy requirement drops to “only” the entire historical power consumption of humanity.

I’M NOT saying it’s aliens, but… No, I’m just not saying it’s aliens, full stop. It is never aliens. Reports of a strong radio signal by astronomers observing the star HD 164595 sent the internet into a frenzy last week. It has now been confirmed as having a terrestrial source, perhaps an unlisted Soviet satellite – so more spy-fi than sci-fi. The incident is the latest in a string of potential discoveries, including Proxima b, Tabby’s star and Planet Nine, that have driven a resurgence of interest in finding extraterrestrials not seen since the heady days of ufology, Contact and The X-Files in the 1990s. “There is one possibility I’m willing to entertain: a Like Fox Mulder, we desperately sentient, self-replicated AI want to believe that aliens are out created to roam the stars” there. In recent years, this desire has been legitimised by the discovery of HD 164595 is 95 light years from thousands of exoplanets, suggesting a universe filled with billions upon Earth. Any aliens dwelling there will billions of worlds. Given such vast see our sun as just one of 14,000 planetary real estate, aliens must be other stars at the same distance or dwelling somewhere, right? less. Are we arrogant enough to think Although we can’t say for sure, it is our pinprick of light is worth the effort? almost certain that aliens have arisen Of course, the chance is always from the primordial goo elsewhere. there, and that’s why it makes sense Even if the odds of life are incredibly to listen. But rather than expecting

messages from outer space, our best chance of confirming that we aren’t alone comes from the kind of painstaking observations that led to the discovery of those exoplanets. In a decade or so, new telescopes will let us remotely sniff the atmospheres of these worlds, looking for telltale signs of molecules like oxygen or methane. Even then, I won’t be saying it’s aliens. There could be geological explanations for gases, or they might be in concentrations too low to support life. In the end, all we could confidently say is there might be some kind of life – probably microbial – clinging to the rocks of a far-off land. It would be an incredible discovery, finally confirming that the process that gave life to everything on Earth is also operating elsewhere in the universe. If you’re still hoping for a sci-fi future, I’m sorry to pour cold water on your imagination. But here’s a bone. There is one possibility I’m willing to entertain – a sentient, self-replicating AI sent out by its creators to explore the stars and communicate with any civilisation it encounters. Assuming sufficiently advanced technology, such an entity could endure the thousands of years of travel. But would we even understand what it was saying when it arrived? These things would be like the monoliths from the film 2001, so they are likely to be incomprehensible. Still, at least we’d have made first contact, if only with an alien’s answerphone. ■ 10 September 2016 | NewScientist | 19

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TECHNOLOGY from social networks as possible, making it all searchable on their own devices. The plan is to let users plug in their medical data as well, and then provide individual health insights by mining that data on their behalf.

Adding value Neil Lawrence at the University of Sheffield, UK, who is an adviser to CitizenMe, says there is a niche for these new personal data firms. But they need to be easy to use and to offer people something of value, he says. “Health data is a domain where this could happen.” Even Facebook – often seen –New apps won’t leave us in the dark– as the antithesis of allowing individuals to manage access to their personal data – is coming around. “When people have more control over their own data, more growth, innovation and value can be created than when they don’t,” Stephen Deadman, Facebook’s We unwittingly give away personal details when we go online – so why global deputy chief privacy not take charge and even earn from it, says Hal Hodson officer, wrote in a report the firm commissioned from Ctrl-Shift. What this means in practice Ctrl-Shift told the delegates. answering a short questionnaire Helsinki, Finland remains to be seen, however. Enter those offering an or sharing their last few tweets. OUR digital footprints are But new laws may force alternative. Next month, London“We have people at the moment constantly being hoovered up. Facebook’s hand and give based start-up CitizenMe will earning £8 a week,” Deakins says. Companies like Facebook and personal data services a boost. launch an app that lets users That’s not much, but it will buy Google use our data to tailor The European Union’s General easily see just what data they you lunch. As people add more services to us, and turn a profit. Data Protection Regulation, which are sharing. “There’s so much valuable data sets to the platform, Yet we have almost no way to kicks in from May 2018, contains information about you spread they’ll be able to earn more. exploit our own data, or discover a raft of provisions focusing on around the internet,” says We could also use our data what others are learning about us. individuals’ control of personal founder StJohn Deakins. “You to make tiresome transactions Now that’s changing. At the data. For instance, it requires can pull that into one place. easier. Australian start-up Meeco MyData conference in Helsinki companies to get explicit consent Then what do you do with it?” is running a pilot project with a last week, hundreds of researchers, for all the data they collect and the For CitizenMe, the answer is bank and telecoms company, in policy-makers and start-ups purposes they use it for – which to give users what Deakins calls which customers’ mobile phone discussed new services that give could stop the current practice of a “digital mirror”. Having pulled “The system can tell you us novel insights about ourselves siphoning up data and sitting on in information about you from things about yourself and and even let us make a return on it until a use emerges. social networks, it then tells you your surroundings that our data. “The best outcome for personal things about yourself and your you may not have known” At present, individuals have data is that we all naturally think surroundings that you may not very little control or say when of data as we think of money,” have known – that you are the using social networks or shopping only single person on your street, data is used to verify their identity says Lawrence: some money we online: we essentially provide keep full control of, some we share for example. when opening an account with data and get targeted with ads. But with trusted parties who manage Such insights are commercially the bank. This saves them the the rise of ad blockers, now used it for our benefit. “The worst valuable. CitizenMe, which started hassle of the usual verification by hundreds of millions of people, out as a market research service, outcome is that we end up with process, and like CitizenMe, shows that the deal is not working. now pays its users small fees if a ‘digital oligarchy’, where data Meeco lets people choose how “We think there’s a perfect storm is controlled on our behalf by they elect to share their data much data they want to share. brewing with personal data,” powerful entities which lack with brands and researchers UK start-up Digi.me helps Jamie Smith of digital consultancy anonymously – for example, by people copy as much of their data accountability,” he says. ■

Put your data to work

22 | NewScientist | 10 September 2016

For more technology stories, visit newscientist.com/technology

ONE PER CENT

Smart wristband keeps truckers on the move

“It will cost us so much it makes my heart ache” President of Samsung’s mobile business Koh Dong-jin gears up to give 2.5 million people a new phone following reports that its flagship Galaxy Note 7 can “explode” while being charged

Automated away The future is now. Walmart, the biggest US employer, announced last week that it would be automating 7000 back-office jobs. After a trial across 500 of its 4600 stores, in which cashcounting, invoicing and accounting were done by machines, the company will now roll out the automated system across its business. Walmart said the 7000 employees will be moved to customer-facing roles.

Scary talent IBM’s Watson is already a jack-ofall-trades. Now the quiz-winning medical expert AI has turned its circuits to film-making. In a collaboration with 20th Century Fox, Watson helped to make a trailer for upcoming sci-fi thriller Morgan. To teach it how to give people the heebie-jeebies, a team fed it 100 trailers for horror films. The AI then identified 10 scenes in the new film, which a human edited together.

10 September 2016 | NewScientist | 23

KIM HONG-JI / REUTERS

JOERG BUSCHMANN/MILLENNIUM IMAGES, UK

information about the driver, which is fed back into the overall fleet management system. Aggregated data from all drivers can be used to plot points in journeys that cause the most stress, so that they can be TRUCKERS are about to get some makes things worse. “Stress on the avoided in the future. company on long drives. A wristband job is a problem, obesity is a problem. As profiles are built up over time, that monitors vital signs will keep In general they are not extremely the system can then advise the tabs on alertness, stress levels and healthy people,” says Gelissen. fleet manager which driver to assign overall health, helping fleet managers “But we can avoid some of the stress to particular jobs, based on their operate their teams more effectively. pretty easily.” physiological state. The amount of Most trucking firms use fleet In October, Gelissen and his team time truckers spend on the road is management systems to reduce costs. will begin trialling a wearable device strictly regulated. But Gelissen thinks They provide detailed information that they hope will add information existing regulations are too rigid and about how vehicles are driven, about a driver’s well-being to the don’t take into account the fact that including braking intensity and fuel equation. Called Ready to Perform, some people may be able to drive consumption, as well as operating the wristband measures galvanic skin more than others. “It’s so strictly conditions, such as weather patterns regulated that every driver is pushed and traffic. “But they know nothing “If you have evidence that to do exactly the same,” he says. about the driver,” says Jean Gelissen at He hopes that monitoring drivers the guy behind the wheel the European Institute of Innovation will eventually lead to more flexible can do more, you can and Technology. regulations. “If you have evidence that stretch things a little bit” Truck driving is a popular the guy behind the wheel is capable occupation. As of 2014, it was the response, heart rate variability and of doing something more, you can most common job in 29 US states. skin temperature. An algorithm then stretch it a little bit,” he says. “If But it’s an unhealthy job. A recent determines stress and alertness there’s a chance he is losing attention, study found that over two-thirds levels as well as sleep quality, which you should do less.” of drivers were obese. Many have can be used to predict when the driver Responses from drivers who took from cardiovascular disease and is likely to fall asleep at the wheel. part in a preliminary trial last year hypertension. Frequent sleep A connected tablet in the truck were positive. “For the driver, it is very deprivation from overnight drives cab provides constant biometric good information,” says Gerard de Graaf, who has been trucking around Europe for 26 years. “One guy found out he had sleep apnoea.” The system also lets drivers track each other. You can see if your friend is having dinner nearby and meet up, says de Graaf. Dominique Bonte at ABI Research says that this sort of monitoring technology will be crucial even as we start to see driverless trucks hit the road. At least to begin with, human drivers will still need to sit in the cab in case of an emergency. This would likely be the case in platooning — something the UK government is considering. Here, a convoy of self-driving vehicles follow a lead truck with a human in charge. “If the driver needs to take over, then the system would need to be sure that the driver is ready, healthy, aware and understands the situation,” says Bonte. “All technology ultimately is about utilising our assets more effectively.” Until the industry becomes fully automated, that –Keeping tabs on truckers– means humans. Richard Kemeny ■

REUTERS

TECHNOLOGY Robot guard powerless to stop food thieves

KNIGHTSCOPE/WENN

IF PEOPLE stealing food right under the eyes of a bot is anything to go by, RoboCop is still a long way off. In a twist on a psychology experiment in which seeing a picture of eyes makes people behave more honestly, Guy Hoffman at Cornell University in Ithaca, New York, and his colleagues put a robot with moving eyes in a student common room to guard a table of snack food labelled with a reserved sign. A hidden camera captured what the hundreds of passers-by did. Seven per cent helped themselves to food, only slightly fewer than the 8 per cent who did when the table was unguarded. Just 2 per cent pinched a snack when a human was sitting at the table. Many seem to have been testing the robot’s capabilities, curious about whether it would stop them or if they could outwit it. One student told his friend to turn the robot around so he could take the food. Another was recorded saying, “It’s not listening. It’s a robot, we could take a cookie.” Sean Welsh at the University of Canterbury in New Zealand isn’t surprised. He says that unless a robot intervenes, we should expect people to ignore it. “The robot is no more a moral agent than the sign,” he says. “I’d like to see the robot look disapprovingly and make some protest noise at people reaching for the snacks.” Aviva Rutkin ■

“Twitter has suspended 360,000 accounts for promoting terrorism, but is it failing to do enough?” The families trying to sue Twitter may not be successful, but their attempt raises an important question. Who, if anyone, is responsible for policing the internet’s front lines? –Could be for a propaganda post– Social networks have their work cut out if they wish to weed out extremists. In August, Twitter announced it had suspended 360,000 accounts over the last year for promoting terrorism. But last month, the UK parliament’s Home Affairs and steal information. Committee argued that tech Some of this activity is carried giants are “consciously failing” out by people with fake identities, to stop their platforms being some by bots that make spam used to spread extremism. “These posts. For example, they can flood companies are hiding behind popular hashtags with messages their supranational legal status to promoting a particular cause or pass the parcel of responsibiltiy ridiculing opponents. and refusing to act responsibly in The report also documents case they damage their brands,” incidents of “catfishing”: the it argued in a report. use of fake profiles of attractive It’s not a problem for tech women to befriend people. The companies alone to solve. NATO Taliban has reportedly used this recommends that nations trick to tease information out of establish “a heightened social Australian soldiers on Facebook. media presence”, with academics, But it is ISIS that exemplifies this journalists and politicians modern approach to extremism, encouraged to speak out online relying heavily on social media to refute misinformation. to spread its message and recruit Giselle Lopez at the PeaceTech supporters around the world. Lab in Washington DC also thinks Gregory Asmolov at the London this is the best approach. “The School of Economics thinks social focus should be much more on media stirs things up because it positive messaging,” she says, brings violence and war home citing Haqiqah, an online to people, no matter where they magazine founded by Muslim are. “You go online and you find leaders in the UK to counter the yourself in a conflict-laden ISIS message. In a war of words, environment.” every voice counts. Aviva Rutkin ■

Extremists wage war with retweets and likes

IN NOVEMBER 2015, an ISIS operative shot and killed two US military contractors in Amman, Jordan. Last week, their families filed their third lawsuit against Twitter. They are blaming the social network for the attack. “For years, Twitter knowingly and recklessly provided ISIS with accounts on its social network,” they claim in their complaint. “Through this provision of material support, Twitter enabled ISIS to acquire the resources needed to carry out numerous terrorist attacks.” Twitter and Facebook have become theatres of war. In a report released earlier this year, the NATO Strategic Communications Centre of Excellence outlined how social networks allow states and militant groups to “blur the distinction between peace-time and war-time activities”. Thanks to social networks, they now have new ways to share propaganda, –Stop, thief!– recruit people to their cause

24 | NewScientist | 10 September 2016

Social networks also blend personal updates and world news, making international disputes feel intimate and urgent. It can polarise societies and increase instability by destroying ties between friends and families on different sides of a conflict. This happened in the run-up to Russia’s invasion of Ukraine in 2014, for example.

INTRODUCING THE SECOND IN A NEW SERIES OF WHITE PAPERS FROM NEW SCIENTIST What’s the future of business? We at New Scientist decided to take a look at how three of the key drivers of business – energy, money and automation – might change over the next decade. To do that, we’ve asked three writers with deep understanding of these areas to tell us how they think the future could unfold, and how it might confound our initial expectations. The author of our second GameChangers report in the series is Steven Cherry, who for 15 years covered the work sector for IEEE Spectrum, and now directs TTI/Vanguard, a members-only forum that explores the impact and implications of future technologies for senior business leaders. In his report, Cherry examines the arguments for and against the idea that automation will ultimately outsource every human job, and explores the paradoxes inherent in both. If cognitively complex jobs are the only ones that are safe, why is there still such high demand for cashiers? If automation generates new jobs, why is GDP slowing? And when can you expect the robots to take your job? To find out, register to download your free copy of GameChangers: Automation and Artificial Intelligence today.

Sally Adee Editor, GameChangers

GET YOUR COPY NEWSCIENTIST.COM/GAMECHANGERS

ABOUT THE AUTHOR Steven Cherry is the Director of TTI/Vanguard, a membership forum based in New York that explores future technologies. Previously he was a journalist and editor at IEEE Spectrum, the magazine of the Institute of Electrical and Electronics Engineers. Prior to that he was an editor at the Association for Computing Machinery (ACM). He founded and co-hosts the award-winning podcast series, Techwise Conversations, which covers technology news, careers and education, and the engineering lifestyle.

GAME CHANGERS AUTOMATION AND ARTIFICIAL INTELLIGENCE IN THIS EXCLUSIVE NEW REPORT FIND OUT:

] Why every technological breakthrough takes twice as long as we expected, but we’re still not prepared for its arrival ]Why GDP is an increasingly limited tool for measuring productivity, and what that means for jobs and automation ] Which jobs might be safe – and which won’t

APERTURE

26 | NewScientist | 10 September 2016

Desert hunter HE’S coming right at you. This striking image of a pharaoh eagle-owl (Bubo ascalaphus desertorum) was captured at dawn in dunes of the United Arab Emirates. As well as being found across the deserts of North Africa and the Middle East, pairs have been seen nesting on the pyramids of Egypt. The photographer, Xavier Eichaker, had to move sharply to avoid being attacked. “It’s a male, and it was pretty aggressive,” he says. “Each time I was near the nesting area, it would come straight at me, and I managed to take this shot one morning just before ducking into my hide. I just had to be ready with my camera.” The backdrop is a large sand dune facing the rising sun. Alongside the owl’s shadow is that of the only tree in the area – a favourite perch from which the owl would hunt. Eichaker also captured the below image of an owlet apparently bemused by a live mouse. A parent had deposited the rodent next to the infant to train it how to track and kill prey. “The bird doesn’t appear to know what the mouse is,” says Eichaker. Andy Coghlan

Photographer Xavier Eichaker Biosphoto

10 September 2016 | NewScientist | 27

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Collective genius Working together enables tiny ants to do very clever things, and it could teach us better maths and robotics, finds Peter Hess 

ARRO Colorado Island is tiny and sits in the middle of the Panama Canal. Here, below the forest dome, a diminutive predator scuttles over dead leaves and along narrow branches. Nearly blind, this Eciton army ant follows a trail of chemical signals laid down by her sisters. She pushes forward, relentlessly, in search of prey. Whatever she finds, she’ll bring back to the nest to share with her colony. But then she stops. The ground has dropped away in front of her. There is no scent trail, just empty space. Other members of the colony that were following begin to climb over her. Now, instead of walking in a line, they grip hold of one another using hooks on their feet, adding body after body to build an impromptu bridge. More and more join in, until they traverse the gap. And there they remain until the entire foraging party, numbering hundreds, has crossed. Then, as suddenly as it came into being, the bridge disperses, and the ants continue on their way. How do these creatures achieve such an impressive feat of coordination with very limited brainpower and no overview of the situation? That’s the question a group of researchers working on Barro Colorado Island set out to answer. Their efforts have revealed how ants use simple cues to organise themselves into complex living structures. It’s a wonder of nature, and it could offer insights for engineers, mathematicians and robot designers. What’s more, it might even shed some light on our own interactions. >

MARK MOFFETT/MINDEN PICTURES

B

Master builders: ants possess remarkable construction abilities

Being part of a bridge may not be as demanding for an individual ant as it might seem

“How do ants achieve such feats with very little brainpower and no overview of the situation?”

Coordination is not by sight or smell but by detecting the forces produced by other ants

near the apex of the V and then moved towards its mouth, becoming longer and wider but rarely creating a straight path. Why would they do that? The researchers suspected the ants were making a cost-benefit trade-off. “If they put too many individuals into the bridges, it’ll impact foraging activities,” says Garnier. It appears that on a moment-to-moment basis, they make collective, instinctive decisions about how the group should best allocate labour between bridge-building and foraging. That’s quite a feat, given that each ant has little awareness of the broader context of its actions. All they have to guide them are local knowledge and their senses. (See a

ALEXANDER WILD

Eciton army ants are not the most obliging research subjects. “They bite and sting at the same time, which is fun,” says Matthew Lutz of Princeton University. But that’s not the biggest problem. They are also nomadic, so you can’t keep them in one of those plastic ant farms you may have had in your school science lab. “The main challenge is to bring the lab to the ants because you can’t bring the ants to the lab,”says Simon Garnier of the New Jersey Institute of Technology in Newark. That is exactly what he, Lutz and their colleagues did. Each day, an Eciton army ant colony builds a temporary home, or bivouac, which can be hundreds of metres from the previous day’s site – so wherever the ants were yesterday is probably not where they will be today. After locating the new territory, the team blocked the foraging path using a V-shaped obstacle on its side, with the long edge in front of the ants. This forced the ants to take a diversion – first left, then right – or to form a bridge over the gap created by the mouth of the V. Then the researchers adjusted the construction to narrow or widen the gap, and watched to see how the ants would react. They found that the ants did build bridges to create a shortcut, rather than going the long way around. However, these bridges did not take the shortest possible route. Instead, the ants created dynamic structures that started

video of ants building bridges in the online version of this article at bit.ly/issue3090.) Yet Eciton army ants build more than just bridges. When walking along a vertical surface, such as a wall, individuals will stop and hold themselves against it. “Over time, that builds up to create a safety net or scaffolding so other ants will be caught if they fall,” says Lutz. He suspects this behaviour follows the same simple rules as bridge-building. “It doesn’t make sense for them to have some kind of different mechanism for each of these things,” he says. So how do they do it? The team’s field experiments suggest that the guiding force is the degree of contact between each ant and other members of its group. When traffic flow becomes interrupted, bodies pile up, and this increases the chance that an ant will stop and become part of a structure. If traffic intensifies, more ants add their bodies to the bridge to increase its capacity. Eventually, the jam clears up, decreasing contact and increasing the likelihood that an ant in the structure will unhook from the others and continue along the foraging path. Using this simple mechanism, the ants continuously modify the length, width and position of their bridges. What’s more, when the researchers made a computer model to work out what construction would give the best cost-benefit trade-off, they found that it matched the dynamic bridges they had observed. In other words, the colony is able to effectively manage its resources, allocating enough bodies to building while at the same time maximising

ALEXANDER WILD MICHAEL RUBENSTEIN/NORTHWESTERN UNIVERSITY/HARVARD UNIVERSITY

the amount of foraging it can achieve. A similar mechanism is probably used by other ant species to coordinate their collective behaviour. Think of the classic image of a group of ants carrying absurdly oversized prey. Like bridge-building, the awkward endeavour is made possible by dynamic adaptations. “By exerting forces on the load and detecting counterforces, each ant can use that to adapt its own behaviour,” says Stephen Pratt of Arizona State University in Tempe, who has studied the behaviour in Aphaenogaster ants. They are not watching or smelling each other. “They’re using the load itself as a nexus to guide behaviour.” Such cooperation is impressive, but it is also a conundrum. Surely it is in each individual’s best interests to let the others work together and then simply take the benefits? Why would an army ant become a building block in a bridge when it could just cross the bridge made by others?

“Swarm robots use a kind of distributed intelligence very similar to that of social insects”

Lutz suggests one possibility: being part of a bridge is easier than foraging. He suspects that as soon as an ant joins the construction, it goes into a low-energy state and simply hangs there by its hooks. A forager, on the other hand, risks her life killing prey. But there is a more fundamental reason for cooperation among colonial insects: they are not really in competition with one another. In evolutionary terms, competition comes down to producing more offspring, but ants in a colony are closely related sisters and only one, the queen, reproduces. “An ant is not in a position to make profit on its own,” says Deborah Gordon at Stanford University in California, who studies harvester ants. She likens it to a cell in a single organism. But there is one key difference, in that the colony’s intelligence is distributed among its component parts. That makes it a “superorganism” capable of unique behaviour and adaptations that individual ants cannot achieve. Such activities are classic examples of “emergent” behaviour – group-level action that is more sophisticated than the sum of its parts. And that makes ant building more than a mere natural curiosity.

Colonial robots Such behaviour is the inspiration for swarmintelligence researchers seeking to program phalanxes of relatively simple robots that are both autonomous and cooperative. The big challenge is coordination. Instead of having a central processing unit, the robots interact at the local level in response to local conditions. “Swarm-based robotics has introduced a new kind of distributed control very similar to the one used by social insects,” says Guy Theraulaz at Paul Sabatier University

in Toulouse, France. These swarm robots can work alone or in conjunction with many others. They have many potential uses, from finding cracks in high-rise buildings to performing search-and-rescue operations in dangerous environments. So far, these ideas haven’t been realised. One of the most sophisticated swarms to date has been created by the Self-organizing Systems Research Group at Harvard University. It consists of 1000 small, inexpensive robots that use local-level interactions to assemble themselves into two-dimensional shapes. They are not exactly the capable, versatile, autonomous machines that roboticists dream of – but it’s early days. Some people believe we can cash in on collective intelligence without the need for robots. “Don’t look at ants as little robots we want to build,” says Ted Pavlic at Arizona State University. Instead, he says, we should ask what sorts of problem the colony solves. For example, when ant colonies are given multiple different food sources with varying nutrient contents, they always forage what the colony needs. In effect, says Pavlic, they are solving multivariable maths equations: if they allocate more foragers to one food source, they have fewer to allocate to others. “We have models with the exact same mathematics, like managing power on a smart grid,” he says. We manage such systems centrally, making conscious calculations of costs and benefits, whereas the colony manages without central control. “Working out how ants do this teaches us new things about the essence of the problems,” he says. “Ants are not just automatons following basic rules. They have properties that really blow your mind.” Getting to grips with how ants team up to complete tasks could have many applications in engineering. However, a bigger potential prize lies in working out how the colony’s intelligence is greater than the sum of its parts. Such emergent behaviour occurs in complex human systems including stock markets, democracies and even our brains. Our intelligence, for example, can be viewed as an emergent property of a huge colony of neurons in our head. That means ant antics could give us insights into our own activities. “A lot of things in human society are based on self-organising principles,” says Garnier. “The same principles that organise ant colonies organise human behaviour.” ■ Peter Hess is a writer based in New York 10 September 2016 | NewScientist | 31

DAN PAGE

32 | NewScientist | 10 September 2016

COVER STORY

HOLES IN REALITY Start playing with particles that don’t exist and you’ll see just how strange matter’s building blocks are, says Andrea Taroni

HEN you hear the word “particle”, what image floats into your mind? Chances are you’re thinking small, and then some – like the tiniest billiard ball imaginable. Indivisible chunks of matter pinging off each other in the vast expanses of space, or jostling for position in a crowded chunk of stuff. Chances are, too, you’re nowhere near the vision of particles painted by our best picture of how they work, quantum theory. This says that despite making up stuff that definitely has a size – ourselves, the paper or screen you’re reading this on – particles occupy a point in space precisely zero metres across. While you’re chewing that one over, you might consider how quantum theory also allows these size-zero particles to occupy multiple places at once, or be “entangled” so the state of one becomes inextricably bound up with the state of another. But even that doesn’t prepare you for the latest assault on any common-sense conception of a particle that physicists have been preparing. Strike the billiard balls from the table. An alternative breed of shape-shifting particles can be split up, change their mass, and be combined with other stuff to make more than the sum of the parts. These particles don’t seem to exist in any way that makes sense, and yet we are increasingly bending them to our will. The results are reshaping technology, from superconductors to quantum computers — and helping us probe deeper into the fabric of reality than ever before.

W

It was Einstein who began to blur the lines of what we think of as the basic building blocks of reality. In 1905, he proposed that light – at the time largely considered to be a space-filling wave, given its ability to interfere with itself, diffract around corners and so on – could also be seen as particles. He later called these photons. It was the beginning of what came to be known as the“central mystery”of quantum theory: wave-particle duality. This principle says that neither a wave nor a particle is a perfect way to think of a photon of light, an electron orbiting an atom or any of the particles at the heart of the atomic nucleus. Sometimes they are best thought of as one, sometimes the other. This duality was a profound insight. But it became even more profound when we began to apply it not just to particles knocking about in free space, but to the goings on within solid materials made of very many particles jostling around for position. Take what happens when you set a flame under a lump of table salt. The individual atoms all start rattling around a tad more enthusiastically, setting up waves of vibrations. In 1932, the Soviet physicist Igor Tamm realised he could treat these waves as particles, mathematically at least. He called them phonons. Phonons have since become a staple, helping us for instance to understand processes such as superconductivity, in which electrons flow through a material with almost zero resistance, and opening the way for

devices that turn heat into electricity (see “Five particles that don’t exist”, page 34). Because they emerge from the movements of more traditional particles, phonons are called emergent particles or quasiparticles. “Phonons are not actually real,” says Jon Goff, a physicist at Royal Holloway, University of London. “They are really just a way of simplifying a very complicated problem.” You can think of a quasiparticle as a little like a Mexican wave at a sports match. The only physical movement is people jerking their arms up and down one after the other and yet something seems to be travelling through the crowd (see diagram, page 31): a movement of energy that amounts to a quasiparticle. Since Tamm’s work, we’ve steadily discovered a whole zoo of such beasts roaming the interior of solid materials. Another species arises from spin, a quantum property that is the basis of magnetism. Spin works something like an arrow on an atom pointing north or south; when all the spins in a material are aligned, you have a magnet. But spins can also flip into and out of alignment, creating a Mexican wave effect that can be treated as a particle known as a magnon. Like phonons, magnons are proving practically useful, helping us to develop low-power “spintronic” computers that exploit atomic spins rather than currents of electrons. Phonons, magnons and the like exist in a kind of twilight world: useful to work out how things work, but doubtful as entities in their > 10 September 2016 | NewScientist | 33

FIVE PARTICLES THAT DON’T EXIST PHONONS

MAGNONS

E XC I TO N S

Electric cowboys

Sultans of spin

Plants’ secret weapon

Smashing protons in CERN’s Large Hadron Collider led to the discovery of the Higgs boson. It couldn’t have happened without phonons. At normal temperatures, phonons are collective oscillations of atoms that shuttle heat around solids. But at very low temperatures, these quasiparticles act as cowboys that corral electrons into herds that move as one with almost zero resistance. This is how lowtemperature superconductivity arises, and the huge electromagnetic fields superconducting magnets create are what curves protons round the LHC’s circular racetrack. Such magnets are also used in MRI scanners, where they force oxygen atoms in tissues into a dance that emits traceable radio signals. Phonons are also key to the workings of fledgling thermoelectric materials. These convert heat into electricity, with the long-held dream of allowing a car’s waste engine heat to power its electrics.

Imagine a computer that, when you flipped the on switch, came on at exactly the point you’d left it. That’s the promise of magnons, quasiparticles that emerge from waves of flipping spin, a quantum-mechanical property of atoms that is the origin of magnetism. In standard PCs and smartphones, working memory is stored as units of charge, which dissipates when the device is switched off. With magnons, stored information would not dissipate until the magnetic field was changed, regardless of power supply. Spintronics, as this idea is called, would have other advantages. It uses less power, so chips can be pushed closer together without overheating — a problem that is plaguing further miniaturisation of transistor chips. Magnons can also be prompted to organise by electromagnetic waves, so computers could become entirely wireless.

Earth receives more energy from the sun in an hour than the entire human population uses in a year. Plants have perfected the art of capturing that juice – thanks to excitons. Inside a plant’s leaves are light-harvesting proteins. Their electrons absorb photons, and the energy kick pings them out of position, creating a “hole”. The electron and hole then link up to form an exciton, which can be transported around the plant’s photosynthetic machinery. When they get to where they’re needed, the electron and hole recombine, releasing energy that is used to split water into hydrogen and oxygen, a key stage in making sugars from sunlight. This reaction ultimately supports all life on Earth, and we’d love to mimic it in solar cells. In 2013, researchers at the Massachusetts Institute of Technology found a way to directly image excitons, a significant step to making that happen.

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“The particles are just smoke and mirrors, handy mathematical tricks and nothing more. Or are they?”

DAN PAGE

own right. But these half-existing particles aren’t even the half of it. Quasiparticles can exist, it turns out, even when nothing is there. That discovery first came in 1947, with a seminal moment for the history of computing. William Shockley, a solid state physicist at Bell Labs in New Jersey, and his team were trying to perfect the transistor, an on-off switch for electrical current. They were using semiconductors, materials whose atoms are deficient in electrons. It had been known for a decade or so that this would create gaps of nothingness, like the empty square in a sliding puzzle. But no one thought these “holes” were anything more than the absence of an electron. Shockley proposed that the hole was actually a particle in its own right, something like an electron that carried positive charge. It turned out to be the crucial step. Only by treating holes as independent entities could you understand how they flow through areas rich in electrons without getting filled and disappearing. The result was the kind of semiconducting transistors, formed by junctions of materials rich in electrons and holes, that still flip and switch in their billions inside computer chips today. Since then, we’ve learned that an electron and a hole can be made to combine – in which case, you don’t get zero as you would if you

added +1 and -1, but a whole new type of particle, the exciton. Plants got there long before us: we now know the exciton is integral to photosynthesis (see “Plants’ secret weapon”, above). So, particles that don’t exist and yet do; that are made of nothing at all and yet can be added to something else to make more: is there any limit to how elastic we can make the idea of a particle?

One red line might be the idea that a particle is something that has a set mass. But even that is breached by what happens within a material such as graphene. Graphene is much heralded for its superlative properties of electrical conduction. That’s down to its structure of carbon sheets just one atom thick, which forces its electrons to interact with one another. Rather like cyclists in a peloton, they end up whizzing

MAJORANAS

WEYL FERMIONS

Quantum heroes

Ambidextrous electrons

Wave slaves

If you ever want a true multi-tasker, go for a quantum computer. These as-yet imperfectly realised machines use delicate, indeterminate quantum states to weigh up lots of solutions to a problem all at once, as long as no disturbance from the environment breaks the quantum spell. Majorana quasiparticles could make quantum computing more robust, supplying “qubits” for quantum number-crunching. A sort of massless electron, Majoranas come in pairs, with each particle acting as a half of the whole. That means you have two copies of all the information they contain, so in theory Majorana qubits should be far less vulnerable to external noise. But these qubits exist in the midst of a huge background of other electronic effects, and isolating the Majorana information is tricky, says Attila Geresdi, who studies these systems at QuTech in Delft, the Netherlands.

Weyl fermions are like a shy cousin of the electron. Predicted mathematically almost 80 years ago, they have two key properties: they have no mass, which means they can move very fast, and they come in mirror images of each other, like right and left hands. This handedness, or chirality, means Weyls are resistant to interference from sources that don’t match their handedness. This in turn means they are difficult to scatter, and streams of the two types of Weyl fermion can potentially flow close to each other without interfering. Some think these properties could make them the basis for highly sophisticated computer processing well beyond spintronics (see “Sultans of spin”, left). But since materials that host Weyl fermions were only created recently, it is early days in the field of “Weyltronics”.

The phenomenon of the Mexican wave shows how something that looks like a moving particle can be created – even when no particle is moving

along faster as a collective than they can individually, at close to light speed. The way we explain that is by saying graphene is still populated by electrons – but electrons that have almost no mass. It’s a mathematical trick, to be sure, similar to the one Tamm used when he dreamed up phonons. But unless you accept that graphene’s electrons have pared down masses, the material’s amazingly good electrical conductivity is hard to explain. And graphene is just the beginning. We are coming to realise that we can engineer solids in all sorts of ways to produce particle-like effects unseen in nature. Take Majorana fermions, particles with no charge and no energy that are their own antiparticles. Predicted in the 1930s by the Italian physicist Ettore Majorana, these particles have never been seen in the wild, aside from unverified suggestions that neutrinos might be their own antiparticles. But we can now make them in the lab. In 2013, Leo Kouwenhoven and his team at the University of Delft in the Netherlands set up a Mexican wave among electrons squashed into a one-dimensional wire with little room to manoeuvre, and discovered that the electrons that peeled off at either end of the wire acted as a Majorana pair. One potential use for these particles is as “bits” in a future super-powerful quantum computer.

Then there are Weyl fermions. Last year, three research groups reported making these long-hypothesised particle pairs. These mirror-image particles are made from underlying waves of spin that are a bit like right or left-handed knots, a property that might add another dimension to spintronic computing. For all their usefulness, you’d be forgiven for still thinking quasiparticles are so much smoke and mirrors: handy mathematical tricks, but nothing more. There’s still a clear distinction between them and the particles that are the building blocks of matter – the sort you can bash together a particle accelerator. Perhaps not. In May, Rupert Huber at the University of Regensburg in Germany and his collaborators unveiled the first quasiparticle collider. They took a semiconductor called tungsten diselenide and used laser pulses to split apart excitons inside it into their constituent electron and hole. Then, reversing the pulses, they could smash the two bits into each other (Nature, vol 533, p 225). The excitons behaved as you would expect real particles to behave. The electron and the hole mutually annihilated, producing a photon, just as an electron does when it hits one of its antimatter equivalents, a positron, at high speed.

Huber reckons the equipment could crack open other quasiparticles, too. Top of his list are trions, charged quasiparticles made from two electrons and one hole. Unlike excitons, it should be possible to accelerate these and dash them into each other as complete entities. Experiments like this, he says, might help find the point where quasiparticles stop acting as if they were real. Because their behaviour is behind so many mysterious but useful phenomena, from photosynthesis to quantum computing to superconductivity, he thinks it could be a fruitful quest. “My dream is to use quasiparticle acceleration to track down some of the key enigmas of modern-day physics,” he says. So what, after all, is a particle? That’s a question that’s been bugging us ever since Einstein first proposed light could be made of particles. In all likelihood it will continue to bug us. Perhaps ultimately we’ll have to accept that it’s all just maths, and equations are all that can guide us in understanding the workings of matter. But if we want a deeper answer than that, chasing particles that don’t exist into the cracks between atoms might just be our best shot. ■

As long as individual people (particles) move randomly, no influence travels anywhere QUASIPARTICLE EXCITATION

There’s no net movement in a Mexican wave either, and yet an “excitation” of energy passes from left to right: a quasiparticle

Andrea Taroni is chief editor of the research journal Nature Physics 10 September 2016 | NewScientist | 35

Teaching a machine how to argue can’t be a good idea. Oh yes it can, says Gilead Amit

N DOUGLAS ADAMS’S novel Dirk Gently’s Holistic Detective Agency, a computer program called Reason can retroactively justify any decision, providing an incontrovertible argument that whatever was decided was the right thing to do. The software proves so successful that the Pentagon buys it lock, stock and barrel, shortly before a dramatic increase in public approval of military spending. We’re not quite there yet. Machines may have beaten us at remorselessly logical games like chess and Go, and they are increasingly giving us a run for our money at games of bluff and chance like poker. But no computer has ever come close to beating humans where it counts: in an argument. Were one ever able to do so, it isn’t just the ears of the military that would prick up. The first wave of artificial intelligence, able to crunch huge amounts of information and spot interconnections ever more efficiently, gave us search engines such as Google. A machine capable of formulating an argument – not just searching information, but also synthesising it into more or less reasoned conclusions – would take the search engine to the next level. Such a “research engine” could aid decisionmaking in arenas from law to medicine to politics. And with an array of ongoing projects looking to build an argumentative streak into AI, it seems only a matter of time before we’ll be testing our mettle against silicon here, too. Arguing is something humans are peculiarly good at. From polite disagreements over the dinner table to vein-popping run-ins over a parking space or presidential politics, exchanging contrary views is what we do.

I

36 | NewScientist | 10 September 2016

“There are few conversations in which not a single argument is exchanged,” says Hugo Mercier, a cognitive psychologist at the University of Neuchatel in Switzerland. “It’s a behaviour that’s omnipresent.” That is unlikely to be a mere cognitive sideshow. As the world our ancestors lived in grew in complexity, individuals who questioned the truth of each other’s claims would have had a powerful evolutionary advantage. Follow that argument, and argumentativeness could be the fount of all rational thought: our ability to ponder a situation’s pros and cons may have originated in rehearsals for these showdowns. “You are anticipating an argument you might have with someone else,” says Mercier.

And that’s a fact The social roots of human argumentation make it tough for an artificial intelligence not programmed to think like we do. Even IBM’s Watson, the supercomputer that, in 2011, wiped the floor with two human champions of the long-running US quiz show Jeopardy!, was only demonstrating an unimaginative ability to answer factual questions. Primed with over 200 million pages of content drawn from books, film scripts and encyclopedias, Watson was trained to analyse what a questioner wanted to find out and locate the answers in its databanks. In the messy real world, such techniques can only get you so far. “A lot of the questions we encounter in life are not factual,” says Noam Slonim at the IBM Haifa Research Lab in Israel. “Questions where there is no one clear answer.” >

MORGAN SCHWEITZER

10 September 2016 | NewScientist | 37

topic is not immediately obvious. To train Watson in such distinctions, Slonim and his team turned to Wikipedia, surmising that the online encyclopedia’s entries would be a rich source of claim and counterclaim. It turned out to be a gargantuan task – less like looking for a needle in a haystack, says Slonim, and more like searching for specific pieces of hay. “In Wikipedia you have something like 500 million sentences,” says Slonim. “And a claim is not a sentence. A claim is usually hiding within a single sentence.” The work has begun to identify key features that set claims apart from generic statements. Claims, for example, are more likely to mention specific times and places, and to include sentiment words such as “exceptional” or “strong”. Later, the team hopes to shift their focus to flagging up evidence that supports the claim, as well as teaching the system to distinguish between anecdotal data and expert testimony – and learn how much weight to give different forms of evidence. That’s all very well when we want a logical, dispassionate assessment of the facts – but Slonim is the first to admit that it’s rarely facts alone that win people over. “When you are debating with another human being, there is a lot of emotion that somehow influences the discussion,” he says.

“In an argument, it is rarely facts alone that win people over”

38 | NewScientist | 10 September 2016

Once more with feeling In his 4th-century BC treatise on rhetoric, the ancient Greek philosopher Aristotle distinguished arguments rooted in facts and figures (which he called logos) from appeals that rely on the speaker’s credibility and expertise (ethos) and statements playing on an audience’s emotions (pathos). All three strands are readily discernible in public debate

CAROLYN DRAKE/MAGNUM PHOTOS

Users would still have to decide which arguments to trust, of course, just as we decide which links to trust. But in a world where we are often swamped with information, an argument engine could save lawyers, for example, the hassle of trawling through vast archives in search of legal precedents, when a simple press of a button would produce an ironclad summary. Doctors could plug in symptoms and get robust recommendations from case histories on file. Companies might use machines to create arguments for buying their wares. Politicians could secretly test the strength of their manifestos. We might even consider consulting an argument engine before we vote. All of that means Slonim, once ploughing a solitary furrow, is no longer working alone. “I started by saying, let’s build this machine that can generate arguments,” says Slonim. “In 2011, it was only me.” Now he has a team of more than 40 people, and research groups are springing up around the globe. The first question Slonim’s team had to tackle was what an argument is, logically speaking. A rough answer might be that it is a claim backed up by evidence. But then the word claim itself could do with a definition. Producing a foolproof spotter’s guide for an AI is surprisingly tough. By way of illustration, let’s return to the argument for or against selling violent video games to children. The statement “Violent video games increase children’s aggression”is a relevant claim, and can possibly be backed by evidence. The statement“Violent video games should not be sold to children”, however, is a statement of opinion, and just reiterates one side of the argument. Something like “Governments should not restrict the activities of free citizens”, meanwhile, might be a relevant claim, but its connection to the

LEFT:IAN BERRY/MAGNUM PHOTOS.RIGHT: PATRICK ZACHMANN / MAGNUM PHOTOS

Since the Jeopardy! success, Slonim has been collaborating with the Watson team to see whether a machine could graduate from facts to arguments. Ask it, for example, “Should violent video games be sold to children?”, and instead of presenting you with links to other people’s opinions, it would synthesise facts into arguments for and against the idea.

today. The successful campaign for the UK to vote to leave the European Union was arguably a triumph of pathos over logos; when Donald Trump punctuates his speeches with the refrain “believe me”, he is employing ethos, urging listeners to respect his authority. Any artificial intelligence that aspires to rise beyond a mere fact-driven research machine to become a fully fledged “argument machine” – one that doesn’t just argue, but argues with human guile – must master these elements of argument, too. But why would we want one? “Argumentation is what makes us capable of resolving conflicts,” Francesca Toni, an AI researcher at Imperial College London, said in a recent lecture on the subject. “And machines capable of this could help us evaluate conflicts easier, better, avoiding mistakes.” Chris Reed, an AI researcher at the University of Dundee, UK, thinks that’s a little utopic, but that argument machines could help raise the level of public discussion. “We should be building a technology to facilitate and encourage good quality argumentation and debate,” he says. In part that would be to counter the existing effects of technology. Easier access to information perversely means we tend to retreat into echo chambers of our own making, where our search histories and social media feeds dictate the information we consume. As a result, opinions and prejudices can become more entrenched. “The growth of social media has radically awakened our

From politics to domestic dramas, emotion is key to the way we argue

individual expressive capacity,” says Carl Miller of the London-based think tank Demos. “But it hasn’t allowed us to compromise any better.” Reed agrees. “This is a deep structural problem. It’s really hard – even if you’re very motivated – to build up a coherent picture of the arguments pro and con on a particular debate.” Over the past few years, he and his team have been on a mission to seek out good arguments, then dissect and rework them into a form that can be used to train an AI to argue like we do. It’s a quest that has led them to some unexpected places. The boisterous debates in the UK parliament, for example, are not good reference material: too much performative swagger, and too many procedural interjections and references to previous debates. “There is much less quality argument there than you would either expect or hope,” says Reed. Some online forums, on the other hand, contain surprisingly wellstructured arguments, despite users being inclined to wear their heart on their sleeve. Reed’s favourite source is the BBC radio show Moral Maze, in which panellists debate the ethics of an issue of the day. Its quasi-legal cut and thrust, laced with pathos and ethos, is just the thing from which to build a general framework for the essence of human argument. By analysing and providing a classification of the sorts of arguments we use, and how they relate to one another, Reed and his team aim to produce a tool

that can then be used to train an AI. Back in July 2012, they performed their first real-time argument analysis, of a Moral Maze episode on the ins and outs of British colonial rule in Kenya. Claim and counterclaim, and the connections between them, were represented on a giant touchscreen in a form ready to be fed into an AI. It was an oddly satisfying moment, says Reed. “In the same way that a director can appreciate a nicely

“Out-and-out negation of opposing views is a rarity in human argument” configured shot, I can appreciate a nicely configured argument,” he says. His team has since repeated the exercise many times, dissecting episodes of Moral Maze and other broadcast and print sources, plus some online forum postings, and turning them into a public databank of argument maps, accessible at aifdb.org. Analysis is ongoing and the results are not yet published, says Reed, but plenty of insights about the way we tend to argue are emerging. When putting forward a hypothesis that we hold particularly dear, for example, we tend to phrase it using questions rather than statements so as to save face if our argument is rejected. Likewise, outand-out negation of opposing views tends to

be avoided in favour of less confrontational challenges. We rarely ask the bluntest question we can – “why?” – to elicit justification. Reed and his team have also started collaborating with IBM in an attempt to build Watson’s familiarity with webs of human reasoning. Meanwhile, a project started by Ivan Habernal and Iryna Gurevych at the Technical University of Darmstadt in Germany aims to go a step further, analysing not just what sort of arguments we use, but which ones are the most effective. Earlier this year, they asked nearly 4000 people to say which of two arguments, each making the same case in different ways, they found the more convincing – and to explain why. Over 80,000 responses later, they now have a database that can be used to teach computational systems to rank the arguments they process, and so argue more convincingly. “To me the goal is to change somebody’s mind, to persuade them,” says Habernal. Will we swallow it? A fully blown argument machine sounds as implausible as Douglas Adams’s tongue-in-cheek Reason software. It seems hard to believe that anyone would trust a machine to tell them, say, how to vote, or suggest what they should think about a certain issue. Then again, if anyone had said two decades or so ago that we would trust an artificial intelligence to serve up and rank sources of information for us, few people would have believed them. One objection to the idea is that any technology is invariably shaped by the prejudices, witting or unwitting, of its designers – as witnessed, for example, by the recent furore over online ad pickers that displayed higher-paying jobs to male users. An argument machine trained on material with a skew towards liberal newspapers, say, will probably itself develop a liberal slant in the way it makes a case. “The bias in the data we are going to explore will probably be reflected in the output,” says Slonim. So what would be so different between the output of an argument machine and a mainstream edited media source, with its often obvious bias? Undoubtedly a research engine’s ability to synthesise large bodies of information as easily as we can perform a web search will find its uses. But as for a fully blown argument machine browbeating us with its superior reason, that would require overcoming that most cussed trait of human nature: we never believe a word anyone says anyway. ■ Gilead Amit is a features editor at New Scientist 10 September 2016 | NewScientist | 39

PEOPLE

How to get ahead in the brain game Big neuroscience projects are springing up the world over, but China’s has unique advantages, says Mu-ming Poo

You have been chosen to head up China’s new Brain Project. What is it?

It’s a huge undertaking, one of China’s top scientific priorities. It’s a 15-year project that the National People’s Congress approved in March. What does it aim to achieve?

The project has three components, or “one body, two wings” as we say. The body is fundamental research into the neural basis of cognitive function. We’ll be using a wide variety of techniques, from profiling gene expression in neurons to brain imaging. The wings are applied science. One will focus on conditions such as depression and addiction, as well as neurodegenerative diseases of old age, including Alzheimer’s and Parkinson’s. In an ageing population – life expectancy in Shanghai is 82 and rising – it’s becoming urgent to resist the onset of degenerative diseases. We will also look at autism. What’s the third component?

This comes from the information technology and artificial intelligence community. They want to initiate projects that are inspired by the brain. There are two aspects to it. One is to use brain-machine interfaces to develop medical applications, such as neuroprosthetics. The idea is to use brain signals to control machines, to help people with serious injuries. Then there is the information technology part. Even though we don’t know how the brain works, there are many features about it that you can incorporate into artificial neural networks or AI systems to improve them. Those researching AI need brain-inspired computational methods, “neuromorphic” 40 | NewScientist | 10 September 2016

chips – microchips inspired by brain architecture – and devices that take lessons from the brain. Europe, the US and Japan already have big brain projects. What can China bring to the table?

The Chinese neuroscience community is small, about 6000 people. That’s about one-tenth the size of the US’s, for example. So we are not competing, but doing complementary work. We have some advantages, though, including our enormous population of patients, which is 10 times bigger than Europe’s. In China, 9 million people have Alzheimer’s, 2 million have Parkinson’s, 30 million have depression, 9 million have epilepsy. Much effort has already been expended, in many medical centres, to find early markers for these conditions, including genetic and molecular ones. We’ll be searching for biomarkers that will enable early diagnosis. But it won’t be very useful until we pool all the data into a central bank of information. That will be one of the project’s tasks.

PROFILE Mu-ming Poo is director of the Institute of Neuroscience and the Center for Excellence in Brain Science and Intelligence Technology at the Chinese Academy of Sciences in Shanghai. He is chief organiser of the China Brain Project

How will you use that pooled data to tackle neurological disease?

We’ll investigate early intervention. With respect to impaired cognitive functions, one can have drug-based interventions or design brain training programmes to prevent further deterioration. Or we may try physical interventions, including non-invasive methods such as transcranial magnetic stimulation. All these tools must be improved because they are not yet very precise. And many drugs are only in the early stages of development, so we need appropriate animal models, of which the best are non-human primates. That’s another advantage China has over other brain projects.

What gives China its edge with using animals?

We have lots of facilities with large numbers of research primates. For example, we’ve already produced the first monkey model of autism, in which a gene related to autism in humans has been replicated in the macaque. This macaque shows autism-like behaviours in its social interactions. We can carry out some of the tests used for humans in these monkeys, but we can also

non-human primates for research, so we must educate the Chinese public on the importance of this research, and show we are treating the animals humanely. From a medical point of view, there is no question monkeys are needed, because their use saves human lives. Still, some researchers say there are unregulated laboratories in China.

The reason China may have an image problem is there have been cases of neglect in some fields of medical research, for example the use of human stem cells for therapy in unregulated

“In 30 years we should have effective technologies for modifying brain activity” labs. The government has now imposed strict regulation on how stem cell research is done. Animal research is also regulated, and the China Brain Project can help enforce these regulations – it will give us leverage in imposing these ethical standards across the country, as we can inspect every place involved in our research to confirm these standards are met.

LIZ HINGLEY FOR NEW SCIENTIST

You take the long view in your research. Where do you expect to be 10, 20 and 30 years from now?

target the brain circuits affected by the condition to see how we might change those behaviours. Eventually we may have monkey models of depression. That would be very useful; nobody has been able to produce such a model yet. Scientists often move to China because they can experiment on non-human primates more easily there. Is China ethically more lax?

In terms of the animals’ environment and care, we strictly follow the ethical standards of the US National Institutes of Health. Some of our animals eat better than humans: we have a colony of marmosets from Germany, for example, eating imported food because we wanted to give them the food they were accustomed to. Animal rights organisations in China may eventually raise the same concerns as those in Western countries about the use of

Ten years is short, but in terms of healthcare, I hope we will have found good early markers for several major brain conditions. We will be testing various interventions in people with early signs of these conditions. That’s a deliverable goal on that timescale. In 20 years, the rodent models of human conditions will have exhausted their usefulness, so that’s when China’s investment in primate research will show its true contribution and value. And in 30 years, we should have precise and effective technologies for stimulating and modifying brain activity for therapeutic reasons – and perhaps for other reasons. As a society, we will have to work out neuroethical rules to guide how such advanced technologies should be used. What brain breakthrough would you be personally interested in?

For my own benefit, I’d like see the development of an effective interface that could stimulate the brain’s sleep centre when I need to sleep – once we find its precise location, that is. ■ Interview by Olivier Dessibourg 10 September 2016 | NewScientist | 41

CULTURE

Fast forward

Time Travel: A history by James Gleick, Random House, $26.95

ON 28 June 2009, at 1200 UTC, Stephen Hawking hosted a party for time travellers at the University of Cambridge. Among the careful preparations, the most important was to invite guests only after the event had taken place. Much to Hawking’s disappointment, nobody showed up. Travelling through time may never be feasible, but it remains a perennially popular topic in science fiction, philosophy and theoretical physics. In Time Travel, James Gleick provides an absorbing history of the idea, eloquently elucidating the reasons for its enduring appeal. The concept of time travel is surprisingly recent. “Though the ancients imagined immortality and rebirth and lands of the dead,” Gleick observes, “time machines were beyond their ken.” In fact, he traces the trope back to a single work of fiction: The Time Machine, written by H. G. Wells between 1888 and 1895. It tells of an unnamed time traveller who rides into the future on an apparatus resembling a bicycle. His voyage is made possible by the fact “there is no difference between Time and any of the three dimensions of Space except that our consciousness moves along it” (as the Traveller helpfully explains to his temporally challenged friends). 42 | NewScientist | 10 September 2016

His reasoning (and Wells’s story) were inspired by the investigations of 19th-century mathematicians such as Bernhard Riemann. But as Gleick observes, Wells’s vision was equally driven by technology: “Time became vivid, concrete, and spatial to anyone who saw the railroad smashing across distances on a coordinated schedule.” If the literary roots of time travel are The Time Machine, then scientific interest originated with Einstein’s special theory of relativity, published in 1905. In Gleick’s account, these two foundations were mutually reinforcing. Science gave credibility to the fiction, which made the science more accessible. The combination was so potent, and expanded so quickly, that time travel began to seem like a truly timeless principle. Gleick traces its literary pedigree, sometimes to the point of tedium, from Wells to writers

“Today the time machine is no longer obligatory to the game of altering the past – it has been internalised” such as Robert Heinlein and Jorge Luis Borges. He also delves into pop culture, ranging from Star Trek to Woody Allen. Then there’s the science. While Einstein remained sceptical of voyaging through the space-time continuum, his close friend Kurt Gödel mathematically described an alternate universe in which time warped to loop back on itself. Gödel gave the calculation to

RONALD GRANT ARCHIVE

The idea of time travel has fundamentally changed how we think, finds Jonathon Keats

The time travel trope can be traced to H.G. Wells’s The Time Machine

Einstein for his 70th birthday, often checking later whether his theory had been proven. It wasn’t, but Gödel’s “closed time-like curves” continued to bedevil physics long after his death, ultimately inspiring a rebuttal by Hawking, who claimed that time loops violated established laws of physics. Hawking organised his Cambridge party as experimental evidence. Whether or not Hawking has the final say, the concept of time travel has proven phenomenally productive. Within physics, Gleick captures some of the intellectual ferment in his account of the debate about whether time is an illusion. Within literature, he’s particularly incisive in his account of alternative histories, which originated as an accident of time travel. “Travel to the past begins as tourism in the extreme,” he writes. But the sightseers “start tinkering”. Eventually they aim at

history’s greatest villains, and murder Hitler, or slay his mother. Beyond the adrenaline, what makes this compelling is the chance to imagine what might have been. Counterfactual narratives let us examine the past more speculatively, and explore how things can go awry in the present. Is despotism a function of personal charisma or socioeconomic conditions? How do we prevent a holocaust? “Nodal points must exist,” says Gleick, “just not... where we think.” Today the time machine is no longer obligatory. The game of altering the past has been so internalised that Gleick suggests the notion of time travel has fundamentally changed the way we think. To illustrate, he cites our habit of burying time capsules. Only since the 20th century have we sought ways to communicate with the future. Now we tend to interpret any box of coins found under a cornerstone as an effort by ancestors to send us a message.

For more books and arts coverage, visit newscientist.com/culture

The Enterprise reloaded Mick O’Hare beams up for the birthday voyage of the iconic starship

In fact, those old cornerstone caches were votive offerings, not meant to be discovered. In contrast to his enthusiasm for SF, Gleick finds a time capsule “a tragicomic time machine”, moving through time at a rate of one second per second. Few capsules survive, he notes, and why should the future care about us in the first place? But here Gleick neglects the wisdom of his book, forgetting that time travel is experienced in the traveller’s present. Time machines are instruments for exploring the past and future, to augment our current knowledge or enrich our lived experience. Placing items in a time capsule is an opportunity for self-appraisal. Considering how we would like to be perceived by the future is a way of examining what we most cherish. ■ Jonathon Keats’s latest book is You Belong to the Universe: Buckminster Fuller and the future (Oxford University Press)

“THERE are hull breaches on decks 4, 5 and 11, Captain, the starboard nacelle is ruptured along its length, and the bridge has taken a devil of a pounding!” Those lines could come from any episode in any Star Trek series, as a stricken USS Enterprise fights destruction. Except the nacelle is venting wood chips, not plasma. And it’s not phaser damage – it’s paint peeling from the saucer section. That’s because this Enterprise is a 3.5-metre long, 90-kilogram model built 50 years ago for the original series of Star Trek. In an age when computer-generated imagery is synonymous with science fiction, this spaceship is rather quaintly made of wood. “That was pretty much it,” says Margaret Weitekamp, lead space curator and cultural historian at the Smithsonian National Air and Space Museum’s new Boeing Milestones of Flight Hall

mostly hanging up. This took its toll on a model built for a studio: it started to sag. The engine pods spread apart, the nacelles tipped backward under their own weight, and paint cracked as wood expanded and contracted with heat and moisture.

in Washington DC. “That and plexiglass, vacuformed plastic and a good paint job. If you wanted a spaceship on TV, you had to build it and film it.” The Enterprise, designed by second world war pilot Matt Jefferies, broke SF rules, with “no flying saucers, no pointy rockets,” says Weitekamp.“He used ‘aircraft logic’: what do the parts do? These are engines, this is the bridge... it has to seem like you’ve thought through what it would require.” The model’s bridge was on top of the saucer with its curved corridors, engineering was beneath, between the engines. Jefferies left another legacy: Jefferies tubes. These connecting tunnels in the engineering system allowed crew to crawl through the ship’s innards and make vital repairs or hide from invading Romulans. Over the years, the museum has shown the spaceship periodically,

Up close and worried

Planet of the giants: why is the USS Enterprise smaller than a car?

NATIONAL AIR AND SPACE MUSEUM COLLECTION

Star Trek starship Enterprise, exhibition, Smithsonian National Air and Space Museum, Washington DC

Restoring the original (built by modeller Richard Dayton) worried Weitekamp: “When you got up close, you saw all the flaws where they hammered in plexiglass. Some bits were burned, some unfinished and unpolished.” The model was repaired within two years, in time for the 50th anniversary of the first episode of Star Trek on 8 September. Weitekamp stopped worrying: “We’ve done so much,” she says. The new version also updates the lights with LEDs. And painters who worked on the Star Trek franchise, John Goodson, Bill George and Kim Smith, add their own value. “Goodson is fascinated by burn marks, by char, by rust. He transfers that appearance of wear and tear to models.” Tellingly, the Enterprise is the only fictional artefact in the hall, something Weitekamp is very conscious about. She wanted “a nod” to SF, especially to Star Trek and the Trekkie phenomenon, which drove fan conventions, Klingon language and culture, film reinventions – and more. This plays to two of the museum’s big themes: imagination and inspiration. “Star Trek inspired today’s astronauts as Flash Gordon inspired Apollo astronauts,” says Weitekamp. Art imitates life imitates space travel. Engage… ■ 10 September 2016 | NewScientist | 43

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LETTERS EDITOR’S PICK

Searching for a second tree of life From Ralf Dahm Penny Sarchet raises the tantalising possibility that life on our planet emerged not once but several times (20 August, p 26). Recently, DNA sequencing has detected microbial life that resists being cultured. What if there is life that uses a different chemistry to store genetic information? The probability of such “alternative” life having survived the competition with DNA-based organisms is vanishingly small. But what a discovery it would be! Mainz, Germany From Paul Davies Sarchet asserts that all life on Earth is the same life. But only a tiny fraction of microbes have been characterised, let alone cultured and sequenced. Systematic methods of analysis are customised to life as we know it, so wouldn’t pick up life as we don’t know it. For some years my research group at Arizona State University has investigated the possibility of a “shadow biosphere” – a second tree of life descended from an independent genesis. Would we not have found it already? No, for the simple reason that nobody has taken the trouble to look. Tempe, Arizona, US The editor writes: ■ Read about the search for alternative life in our feature “Second Genesis” (14 March 2009, p 28).

To read more letters, visit newscientist.com/letters 52 | NewScientist | 10 September 2016

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There are limits to sacred rights From Guy Cox John H. Evans presents a survey showing that religious believers, who see humans as qualitatively separate from animals, have a greater regard for the rights of other humans (6 August, p 32). He does add the caveat that “it was only about what people think instead of what they do”. The evidence of what happens in practice is rather different. In my lifetime I have seen Catholics and Protestants fighting in Northern Ireland, Orthodox and Catholic Christians committing atrocities on each other in the former Yugoslavia, Sunni and Shiite Muslims fighting to the death in Arabia, Christians and Muslims fighting a dirty war in Sudan and Buddhists persecuting Muslims in Myanmar. The religious view of human rights does not in fact apply to humankind. It applies only to those of the same religious belief. Those of different religions stand back and denounce rights abuses, but those involved (with notable exceptions) do not. For the record, I am a practising Christian who believes that all the evidence shows that differences between humans and other mammals are quantitative, not qualitative. St Albans, New South Wales, Australia From Krista Nelson Evans has good intentions in trying to define what is human and uphold human rights; but I think his method for achieving them is flawed. He seems to feel that the best way to protect humans is to label them as special, even sacred, as a taboo creature not to be touched. Unfortunately there are many ways this can be warped. For example he suggests that maybe we should think of people as made in God’s image. But many

right-wing Christians think that neither women nor people of colour are made in God’s image and accord them lesser rights than white men. Rokeby, Tasmania, Australia From Carl Zetie Your Leader expresses concern that materialists who have a strictly biological definition of humans are less supportive of human rights (6 August, p 5). Surely the most rational answer to the growing evidence that we are “no more” than a species of ape is not to lower our standards for human rights, but to raise our standards for animal rights? Waterford, Virginia, US

Is illogical belief morally wrong? From Edward Weber Shaoni Bhattacharya reviews two books on how people base illogical decisions on emotional misinformation (6 August, p 42). She seemed to make no mention of the possibility that such behaviour could be considered immoral, or that honesty about evidence is moral behaviour. Do those who adhere to nonfactual ideas, even in the face of overwhelming evidence, really have no free will? Are they totally at the mercy of their amygdalae? How can we even have a civilisation if that is all we are? Perhaps one way of addressing the emotional issue is for those whose ethics include respect for evidence to express moral outrage at those who promote unsubstantiated belief over massive amounts of real evidence. It should be clear in our speech and writing that, at least on the issue of respect for evidence, there is little moral difference between a creationist and a holocaust denier, an anti-vaxxer and a perjurer, or a scam artist and a climate denier. Lyndhurst, Ohio, US

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Our empathy sets the bar for animals From Dorothea Rossellini If ever there were a philosophical sideshow, it is the question Aviva Rutkin examines – the role of “personhood” in determining animal treatment (2 July, p 16). As she says, young children and cognitively impaired adults reliably flunk personhood tests – yet we do not think we can treat such people like nerveless lumps of meat. We see that they suffer. That’s the point. From that recognition follows a case-by-case argument for rights and needs. Yes, it is interesting to map which cognitive capacities other animals share with us – but it’s irrelevant to the issue of animal treatment. Notice, too, that we don’t recognise animal suffering because they are sufficiently human, but because we are sufficiently human. Fish gotta swim, birds gotta fly, and Homo sapiens, specialist in social cleverness, can’t help seeing painfully far into the experience of other creatures. You may choose to ignore what you can’t help perceiving. Pity. That’s like being a salmon that never gets to swim; a swallow that refuses to fly. Dorrigo, New South Wales, Australia

Engineering safer banking practice From Liam O’Keeffe Bill Summers suggests banking should be regulated as a profession (Letters, 20 August). The profession that banking really could learn from is engineering. Before the 2008 global financial crisis, banking regulators and practitioners believed self-regulation was best for free markets. Unfortunately, the conditions necessary for free markets to exist

“I think so. Power corrupts and absolute power corrupts absolutely.” Tess responds to our question on whether it’s time to rein in information giants like Facebook and Google (3 September, p 16)

are rarely present and then only briefly. So it is no surprise that disaster eventually strikes. Engineers are trained to understand the limitations of applying theory to the real world and so build in safety factors. If engineering principles had been used to design the new Basel 3 rules, I suspect they would focus on wider measures to prevent the positive feedback loops that caused the crisis. Let us hope financial regulators continue to closely monitor the markets and learn from mistakes before it’s too late. We can’t afford another such crisis. Abinger Hammer, Surrey, UK

Chance would be a fine titanium thing From Stuart Vine I read with interest that the frame supporting the hull of the Mary Rose was built of titanium rather than iron (13 August, p 43). We wished! At the time titanium cost around £70 per kilogram, and the frame weighs around 100 tonnes. TOM GAULD

The supporting frame is steel. Most of the internal supports and some of the bolts are titanium. I helped design those bits. London, UK

We mine richer seams than that From Peter McCarthy You report that there are 6 grams of gold per tonne of rock in the Solwara subsea deposit off Papua New Guinea, “six times what landlubbers get” and that a deposit being 7 per cent copper grade is “10 times what is typical for mines on land” (30 July, p 38). Mike Johnston of Nautilus Minerals goes on to say that these grades have not been seen on land for 300 to 400 years. These statements are true only for open pit mining. Underground gold mines around the world have grades up to 40 grams per tonne mined. While average copper mine grades are around 0.6 per cent, some large mines operate at up to 2 per cent copper. Earlier mines

in South Australia produced copper at much higher grades. Melbourne, Victoria, Australia

Processed food is so often a problem From Ben Haller Anthony Warner urges us to “question the narrative that processed food is inherently bad” (30 July, p 20). Indeed, cooking food yourself is “processing” it. But Warner glosses over the substantive objections to many processed foods: that they often contain very high levels of problematic ingredients such as high fructose corn syrup, salt, sugar and trans fats. They contain substantial amounts of artificial ingredients such as preservatives, stabilisers and emulsifiers, often without as much safety testing as you might think. Ithaca, New York, US From Urs Kleinert Warner’s comment comparing home-cooked and pre-prepared foods is fascinating, if only for its

support of his employer’s agenda. He eloquently refutes claims nobody has made, that homemade meals are always healthier and processed food “inherently bad”. Ignoring research on levels of salt, sugar or dubious additives, he cites a single source, admitting that “it’s a small study and you can’t draw too many conclusions”. Cologne, Germany

Make most pupils above average From Tim Chapman Feedback may be being unfair to the odious Michael Gove, former education secretary for England, in criticising his demand that all children achieve above-average test scores (16 July). It is at least possible for most to be above average. Imagine a class of 10 in which 6 children score 6/10 on a test and 4 score 4/10. Most score above the mean, without any doing particularly well. Allowing for a larger sample and a more realistic variation in scores, all Gove has to do is to ensure a large minority underclass who, for whatever socioeconomic reasons, reliably underperform the slightly more privileged majority. This may or may not be relevant to the understanding of wider Conservative Party policy. Huddersfield, West Yorkshire, UK

For the record ■ Our nearest star is, of course, our own sun (27 August, p 5).

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PAUL MCDEVITT

attained,” he writes. Generally, “the more citations an academic’s papers received, the higher he or she got on the academic ladder”. However, when the study authors ran the numbers again, after subtracting self-citations, the correlation evaporated. A literal case of self promotion?

BAD news, everyone. On 23 August, skywatchers received an ominous red alert from AuroraWatch, after sensors at Lancaster University, UK, registered an off-the-charts spike in geomagnetic activity. Rather than encouraging people to rush to prominent outcrops to see the aurora, a solar flare of that magnitude ought to have sent recipients scrambling into underground bunkers, from which they could emerge months later to rebuild civilisation from the charred remains at the surface. As Feedback is writing this, and you are reading it, this scorching finale obviously never took place. An update posted to the AuroraWatch website later that day announced that the red alert had been cancelled: the source of the disturbance was in fact “caused by University staff mowing the grass on a sit-on mower”.

GOOD news, everyone. Sexism is over, according to the majority of US men polled by the Pew

Research Centre. Of those questioned, 56 per cent agreed with the statement: “obstacles that once made it harder for women than men to get ahead are now largely gone”. Strangely enough, just 34 per cent of women felt the same way. Political leaning also tipped the scales: only 35 per cent of Republicans felt that “significant obstacles still make it harder for women to get ahead than men”, compared with 68 per cent of worrywart Democrats. The results emphasise that there is at least one significant obstacle facing women in the world: convincing half of men that sexism exists. FEEDBACK previously discovered that male scientists’ favourite expert to cite was, invariably, themselves (20 August). Guy Cox is reminded of a study he read in the early 1970s. “It compared scores in the Science Citation Index with academic position

Immortal words from the i newspaper, in which a headline announces: ”Eating plant protein instead of meat reduces risk of death” 56 | NewScientist | 10 September 2016

HE’LL be back – wearing some snazzy yellow shades. Arnold Schwarzenegger is just one of the celebrities spotted toting Swannies, mustard-tinted spectacles that promise to make you “sleep better, burn fat, get focused, feel energised” and most importantly, perhaps, “look cool”. The glasses are designed to block blue light from mobile devices, popularly believed to disrupt sleep cycles and the most fashionable pollutant to avoid since BPA. But how does wearing these glasses help you burn fat, get focused and feel energised? Er, by getting more sleep, according to the Swannies website. You could just go to bed an hour earlier. But for those who can’t give up their late night Twitter binges, it may be cheaper and more convenient to install one of many free apps that gradually reduce the blue light content in your device’s display as the day wears on. Question is, would you “look cool” favouriting the Governator’s photos on Instagram if you did it without a pair of yellow glasses on? PREVIOUSLY, Feedback discussed how scatty naming conventions were confounding attempts to compile stool-related research (27 August). Now scientists have uncovered a new categorisation error: 20 per cent of scientific papers in genetics journals contain mutations produced by contact with Microsoft Excel. Writing in Genome Biology, the authors say that the popular spreadsheet program introduces transcription errors to many genes, converting septin 2 (SEPT2) to a date, and so forth. The bug was most frequently

found in files of supplementary data, “an important resource in the genomics community that are frequently reused”. Feedback reminds geneticists that it’s important to sanitise your tables – both in the lab and beyond.

WATCH out for bored-looking horses. Aleksandra GóreckaBruzda and her colleagues have been studying yawning patterns in wild and domestic varieties, writes Dieter Britz. Writing in Naturwissenschaften, the researchers say that while there was no difference in the frequency of yawning between the two, aggressive colts tended

to yawn more often. They hypothesise that yawning may help to reduce tension. We find a nap helps with both. SELF-CONFESSED pedant John McCallum writes: “The Guardian, reporting on the record hot July, said that it ‘added weight to fears that 2016 will go down in history as the hottest year since records began’.” Why is this to be feared, asks John. If 2016 proved to be the high-water mark in global warming, surely that would be a good thing. “If, on the other hand, there is a subsequently hotter year, then it is unlikely that 2016 will go down in history after all.”

You can send stories to Feedback by email at [email protected]. Please include your home address. This week’s and past Feedbacks can be seen on our website.

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THE LAST WORD Shape of things to come Comet 67P/Churyumov-Gerasimenko has an irregular shape. What size do comets or asteroids need to be before they develop an orb-like shape, and what are the processes involved?

because the underlying rock is warmer and less rigid. Mike Follows Sutton Coldfield, West Midlands, UK

It’s behind you

■ Calculations suggest that any rocky object with a diameter of more than 700 kilometres should be close to spherical. At this size, the body has enough mass to overcome hydrostatic forces when originally molten. Ceres, the largest object in the asteroid belt between Mars and Jupiter, has a diameter of about 945 km and is nearly spherical. Bodies composed of water ice are less rigid than those made of rock, and thus assume a spherical shape at much smaller diameters – around 320 km. If we assume all planets have the same composition and density, calculations also show that the maximum height of any protuberance – such as a mountain – should be inversely proportional to the planet’s diameter. This explains why Mars, which has a diameter roughly half that of Earth, sports a mountain, Olympus Mons, that is more than twice the height of Everest. An added complication is that bigger planets retain more of their primordial heat, which can be traced back to the gravitational potential energy of the gas cloud that collapsed to become the planet. This further reduces the height of their mountains

Many years ago I heard a radio broadcast featuring a beeping sound that always seemed to come from behind me. The announcer said that the sound would have this quality and it did, even when I turned around. It was a plain beep, and the radio only had one loudspeaker. It was a complete mystery to me then and it still is, so can anyone explain the effect?

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submitted by readers in any medium or in any format and at any time in the future. Send questions and answers to The Last Word, New Scientist, 110 High Holborn, London WC1V 6EU, UK, by email to [email protected] or visit www.newscientist.com/topic/lastword (please include a postal address in order to receive payment for answers). Unanswered questions can also be found at this URL.

■ Many people assume that the outer ear is shaped as it is purely to collect sound and channel it into the ear canal. Its shape certainly helps with this task, but the ear is also designed to subtly change the quality of sound so we can distinguish where it is coming from. When a sound comes from behind you, it enters the ear canal from a particular angle, causing it to pass over a specific part of the outer ear. We are not conscious of the way this changes the sound, but our auditory cortex can detect it. When combined with information about the amount of sound received by each ear, this enables us to tell where it originates from. To create a sound that constantly seems to be coming from behind you, a technique

known as dummy-head recording is used. A microphone is placed inside the ear canal of a mannequin head with a realistically shaped outer ear. This alters any sound before it reaches the microphone, meaning that the position of the sound relative to the head is maintained in the recording. When it is played back, you perceive the sound to be behind you, regardless of where your radio is positioned. Toby Bateson Truro, Cornwall, UK

Revolving core I keep reading about how every so often, Earth’s north and south magnetic poles “flip”. How long does it take for this to happen? Moments or years? And does the magnetosphere “turn off” when this change is taking place? Or is it more like turning a bar magnet through 180 degrees, with the poles moving across the planet’s surface and passing through the equator? (Continued)

events, and is why geologists do not give much credence to “polarreversal-doom” scenarios. Over an animal’s lifetime, the changing of fields is unlikely to override other cues that help it navigate, such as prior experience. As an aside, organisms that depended solely on magnetic fields for migration would have died out at every reversal, but this appears not to have happened: the use of multiple cues was far more likely than reliance on one significantly variable prompt. If, for example, magnetic sense disagrees with your rule of “sunrise in the right eye” for a northern-summer migration, organisms that gave more weight to one than the other would have been less successful in terms of migration and offspring survival. Those that blended the two would have survived and bred better. Aidan Karley Aberdeen, UK

This week’s question FLY FISHING (HIC)

■ We know of an underground volcanic intrusion that cooled over thousands of years in which different parts of the structure have preserved distinctly different magnetic orientations. This has been interpreted as meaning that the duration of a reversal event is indeed on the timescale of millennia. This is in general agreement with our (admittedly inexact) theoretical models of these

The other day I fished a fly out of my Chardonnay. In its struggle, it must have absorbed some of my wine. Sitting on my finger, it cleaned itself carefully and I expected it to fly off somewhat erratically. It flew, however, straight and true for as far as I could see it. So does alcohol not affect insects in the same way as it affects mammals? Hartmut Schmid Hope, British Columbia, Canada

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