This week’s issue On the cover 42 Are we alone? We can finally answer the biggest question in the cosmos 30 Selling happiness How positive thinking became big business 34 Bad back? There’s a back pain epidemic. Most treatments make things worse. Here’s why, and what you can do 6 weeks to go! Discover our biggest and best speaker line-up ever at our 4-day festival of science. Find out more at newscientistlive.com 12 Quantum teleportation Now in 3D! 38 Refreezing the Arctic Three ways to engineer the ice cap back 5 Amazon on fire 10 Koala microbiome 17 Spy gliders 14 Pollution and mental health 13 How old is your brain? Vol 243 No 3245 Cover image: Belovodchenko Anton/Shutterstock News Features 6 Brexit hate speech The UK government is using AI to predict spikes in Brexit-related hate crimes 34 Bad back? The most common treatments for chronic back pain may be making it worse News 7 Polio success Wild polio virus has been eradicated in Nigeria, but the battle isn’t over yet 38 Refreezing the Arctic If we want to save the frozen north, we may have to bring the ice back ourselves 20 Dawn of the pyrocene Arctic wildfires could spur a powerful feedback loop 42 Are we alone? After millennia of guesswork, we can finally start finding out for certain, says Sarah Rugheimer Views The back pages 23 Comment Genetic medicine tests the limits of patient confidentiality, says Laura Spinney 51 Maker Build a mini weather station 52 Puzzles Quick crossword, a riddle of ages and the quiz 24 The columnist James Wong delves into claims that fruit is bad for you 53 Feedback Sexy pavement lichen and a robot priest: the week in weird JASON BYE FOR NEW SCIENTIST 26 Letters Using biomass to make fuel is a criminal waste 28 Aperture Shipping glints from space 30 Culture The psychology of happiness feeds a vast industry 8 Coastal erosion Crumbling cliffs prompt communities to retreat 54 Almost the last word Readers explain why water hydrates and dogs roll over 56 The Q&A Niamh Nic Daeid on a paradigm shift in forensic science 31 August 2019 | New Scientist | 1 PALAST CK FE A W BOGES EA OK REMRLY NO A BIR W ININ D G NE W S C IE N T IS T L I V E Accommodation package with 4-day pass 10-13 October 2019 Earlybird discount price: $825* per guest The hassle-free premium experience. Stay close by with like-minded guests and attend an exclusive gala dinner k3 nights at 4-star Crowne Plaza Hotel just minutes from the festival k4 day All-Access festival ticket includes entry to all the stages, the Main Stage Hospitality Lounge and fast-track access kGala dinner hosted by the New Scientist editor Emily Wilson with two exclusive speakers: Andy Smith The British Antarctic Survey Steve Haake The Advance Wellbeing Research Centre Sheffield Hallam University kScience and History of the Docklands guided tour Earlybird discounted price ends soon: $825* per guest If you have already bought a ticket the Earlybird price for the rest of the package is just $570 To book visit NewScientist.com/hotel Queries email hotel@newscientist.com *Based on two people sharing. Single rooms are also available NewScientistLive.com/hotel The 4-star Crowne Plaza Hotel The leader The climate tipping point EVARISTO SA/AFP/GETTY IMAGES Two crises mean irreversible change is no longer an abstract concept YOU rock your chair back, confident you are still in control and can restore equilibrium. Before you know it, you are on the floor, struck by an irreversible change you can’t swing back from. That’s the dangerous thing about tipping points: you don’t know you have reached one until it is too late. Earth’s climate could now be facing at least two. Reports from Brazil’s National Institute for Space Research suggest that wildfires in the Amazon are occurring in unusually high numbers (see page 5). They haven’t yet been confirmed as record-breaking, but many see them as evidence that the anti-environment, pro-agriculture policies of Brazil’s president, Jair Bolsonaro, are driving illegal burning of the rainforest. This is disastrous for the people and wildlife living there, and for the planet. The policies of Brazil’s president, Jair Bolsonaro, have seen an increase in Amazon burning The Amazon is a region of extraordinary cultural and biological diversity, and a huge global sink of carbon dioxide. We need it to have a chance of keeping global warming to a manageable level. Fewer trees means less water vapour being pumped into the atmosphere. Intact regions of forest start to suffer. At some point, the whole may reach a tipping point where the untouched forest dies and the Amazon flips to become a non-forest ecosystem. We don’t know where that point is. Some studies indicate that we could get there if a fifth of the rainforest is lost. Others suggest a tipping point could be reached as soon as 2030. Meanwhile, an unprecedented number of fires are ripping through the Arctic (see page 20). There, the tipping point is of a different nature: a sea-icefree Arctic creating positive feedbacks that accelerate warming. That risk is now so dire that some researchers say we should investigate local geoengineering options to prevent it (see page 38). The law of unintended consequences means that must be a last resort. As for the Amazon, Bolsonaro must be persuaded to about-face, if necessary by withholding aid and trade deals. We know by now what we all have to do. Let’s not test the tipping points. ❚ PUBLISHING & COMMERCIAL MANAGEMENT EDITORIAL Display advertising Tel +44 (0)20 7611 1291 Email displayads@newscientist.com Commercial director Chris Martin Display sales manager Justin Viljoen Lynne Garcia, Henry Vowden, (ANZ) Richard Holliman Recruitment advertising Tel +44 (0)20 7611 1204 Email nssales@newscientist.com Recruitment sales manager Mike Black Nicola Cubeddu, Viren Vadgama, (US) Jeanne Shapiro New Scientist Live Tel +44 (0)20 7611 1245 Email live@newscientist.com Events director Adrian Newton Creative director Valerie Jamieson Event manager Henry Gomm Sales director Jacqui McCarron Exhibition sales manager Rosie Bolam Marketing Head of campaign marketing James Nicholson Poppy Lepora, Chloe Thompson Head of customer experience Emma Robinson Email/CRM Manager Rachna Sheth Head of data analytics Tom Tiner Web development Maria Moreno Garrido, Tom McQuillan, Amardeep Sian Chief executive Nina Wright Finance director Jenni Prince Chief technology officer Chris Corderoy Marketing director Jo Adams Human resources Shirley Spencer HR coordinator Serena Robinson Facilities manager Ricci Welch Executive assistant Lorraine Lodge Receptionist Alice Catling Editor Emily Wilson Executive editor Richard Webb Creative director Craig Mackie News News editor Penny Sarchet Editors Jacob Aron, Timothy Revell Reporters (UK) Jessica Hamzelou, Michael Le Page, Donna Lu, Adam Vaughan, Clare Wilson (US) Leah Crane, Chelsea Whyte (Aus) Alice Klein, Ruby Prosser Scully Digital Digital editor Conrad Quilty-Harper Web team Lilian Anekwe, Anne Marie Conlon, David Stock, Sam Wong Features Head of features Catherine de Lange (parental leave) and Rowan Hooper Acting head of features Tiffany O’Callaghan Editors Gilead Amit, Julia Brown, Kate Douglas, Alison George, Joshua Howgego Feature writers Daniel Cossins, Graham Lawton Culture and Community Editors Liz Else, Mike Holderness, Simon Ings Subeditors Chief subeditor Eleanor Parsons Bethan Ackerley, Tom Campbell, Chris Simms, Jon White Design Art editor Kathryn Brazier Joe Hetzel, Dave Johnston, Ryan Wills Picture desk Chief picture editor Adam Goff Kirstin Kidd Production Production manager Alan Blagrove Robin Burton, Melanie Green © 2019 New Scientist Ltd, England. New Scientist ISSN 0262 4079 is published weekly except for the last week in December by New Scientist Ltd, England. New Scientist (Online) ISSN 2059 5387. New Scientist Limited, 387 Park Avenue South, New York, NY 10016 Periodicals postage paid at New York, NY and other mailing offices Postmaster: Send address changes to New Scientist, PO Box 3806, Chesterfield, MO 63006-9953, USA. Non-exec chair Bernard Gray Senior non-exec director Louise Rogers CONTACT US newscientist.com/contact General & media enquiries US Tel +1 617 283 3213 210 Broadway #201, Cambridge, MA 02139 UK Tel +44 (0)20 7611 1200 25 Bedford Street, London WC2E 9ES Australia PO Box 2315, Strawberry Hills, NSW 2012 US Newsstand Tel +1 973 909 5819 Distributed by Time Inc. Retail, a division of Meredith Corporation, 6 Upper Pond Road, Parsippany, NJ 07054 Syndication Tribune Content Agency Tel 1-800-346-8798 Email tca-articlesales@tribpub.com Subscriptions newscientist.com/subscribe Tel 1 888 822 3242 Email newscientist.na.subs@quadrantsubs.com Post New Scientist, PO Box 3806, Chesterfield MO 63006-9953 Registered at the Post Office as a newspaper and printed in USA by Fry Communications Inc, Mechanicsburg, PA 17055 31 August 2019 | New Scientist | 3 SUBSCRIPTION OFFER Subscribe today * from only $1.91 a week - Free weekly print delivery to your door As a New Scientist subscriber you also benefit exclusively from: - The New Scientist app, giving you instant access anytime, anywhere, including - Current and back issues of New Scientist All issues of New Scientist: The Collection worth $9.99 each! - Full access to newscientist.com with - Over 30 years of archive content - 100+ science talk videos - Early access to magazine features online For easy online sign-up, visit newscientist.com/13565 Or call 1 888 822 3242, quoting reference 13565 * A digital subscription package to New Scientist costs $1.93 a week, made payable by quarterly continuous payment methods News Managed retreat The fight to save coastal dwellings from rising seas p8 Digital privacy Facebook’s data may put millions of gay people at risk p11 Shock waves in space LIGO spots its first black hole-neutron star collision p13 Air pollution Is city air causing mental health conditions? p14 REUTERS/BRUNO KELLY Birds and burgers Crows may have high cholesterol because they eat fast food p7 Amazon fires are on the rise Fires raging across the Amazon have renewed efforts from some countries, companies and individuals to protect the rainforest. Michael Le Page and Adam Vaughan report A LARGE increase in the number of fires in the Amazon rainforest has led to an international outcry and a row over the need for action. Brazilian president Jair Bolsonaro has rejected an offer of $22 million from seven of the world’s richest countries to help tackle the fires, accusing the G7 of colonialism and suggesting the money be used to reforest Europe instead. Many environmentalists also criticised the offer, saying it was too small. Despite Brazil’s rejection of the offer, more money should reach non-governmental organisations trying to save the Amazon rainforest thanks to private fundraising efforts by individuals and companies. Leonardo DiCaprio pledged $5 million, for instance, and Apple said it would donate an undisclosed sum. On Tuesday, the European Space Agency (ESA) said its satellites had detected nearly four times as many fires burning over the past few weeks compared with the same period last year: 4000 from 1 to 24 August versus 1100 last year. There are fires burning in parts of Peru, Bolivia, Paraguay and Argentina as well as Brazil. While wildfires do occur naturally during Brazil’s dry season, almost all the fires are thought to have been deliberately started with the intent of clearing the land. Last week, the ESA said the carbon dioxide released by the blazes in August was the highest for the month since 2003. The fires have also been releasing carbon monoxide, and thick smoke has reached cities such as Sao Paolo. “The past week has been really concerning in terms of the Amazon forest, there is no question about it,” says Erika Berenguer at the University of Oxford. Saving the Amazon is seen as crucial to efforts to limit global warming and preserve The latest on the Amazon online For more on the race to save the rainforest visit newscientist.com/subject/environment biodiversity. The rainforest stores vast amounts of carbon and hosts a rich variety of species. The Amazon is also home to 400 groups of indigenous peoples. These peoples say they are being subjected to a rising number of attacks. “But these crimes go unpunished; they are increasingly encouraged by our national leaders, including the President of Brazil,” Sonia Guajajara, coordinator of the Association of Indigenous Peoples of Brazil, said in a statement. “We are putting our bodies and our lives on the line. If we disappear, so will the world’s tropical forests.” ❚ To learn about tackling a world of wildfires, see page 20 31 August 2019 | New Scientist | 5 News Social media Predicting Brexit-related hate crimes As the UK’s exit from the EU nears, government agencies are trying to pinpoint hotspots of race-related hate speech, reports Donna Lu Reported hate crimes spiked after the UK voted to leave the EU in 2016 6 | New Scientist | 31 August 2019 The team recently established for the first time that an increase in hate speech on Twitter leads to a corresponding increase in crimes against minorities on London streets (British Journal of Criminology, doi.org/c9qh). The pattern is similar to what happens with domestic violence, which often escalates from verbal to physical abuse, says Williams. The team found that as the number of tweets that were antagonistic about race, ethnicity or religion increased, so did the incidence of aggravated crimes, including violence, harassment and criminal damage. A similar study in 2018 found a link between the number of anti-refugee statements on Facebook and violent crimes against refugees in Germany. Relevant government authorities such as police REUTERS/YVES HERMAN THE UK police are monitoring hundreds of thousands of Twitter posts containing hate speech every day. It is part of a pilot project to predict spikes in hate crimes in the run up to 31 October, when the UK is due to leave the European Union. The Online Hate Speech Dashboard is being used by analysts at the National Police Chiefs’ Council’s online hate crime hub, which was established by the Home Office in 2017 to “tackle the emerging threat of online hate crime”. It gathers Twitter posts from across the UK and uses artificially intelligent algorithms to detect speech that is, for example, Islamophobic, anti-Semitic or directed against people from certain countries or with disabilities or from LGBT+ groups. The police chiefs’ council tasked Matthew Williams at Cardiff University, UK, and his colleagues with developing the dashboard so that government organisations could monitor hate speech. The dashboard flags between 500,000 and 800,000 tweets per day as containing hate-related language. About 0.5 per cent of these are from users tagged with precise locations within the UK, which the dashboard presents as a map of hate hotspots. If there is a spike, the information can be passed by analysts to the relevant local police forces, says Williams. Previously, such monitoring had to be done manually. The main aim of the project is to identify patterns of hate speech in the lead up to 31 October to warn police and support organisations of any potential issues. forces and councils may use the information from the hub for counter-messaging on social media. These include awareness campaigns, reiterating zero tolerance for hate crimes and encouraging people to report incidents to True Vision, a national crime reporting hub. Last year, the UK government launched a nationwide hate crime “The dashboard flags between 500,000 and 800,000 hate-related tweets per day” awareness campaign, which included adverts on social media. The hope is that the dashboard will lead to a reduction in online hate speech. It includes information about the trends in hate speech against each group over time, and commonly used words and hashtags in hateful tweets. In addition, it shows networks of tweeters who interact with each other, although their identities are anonymised. These clusters can provide information about how much of the hate speech results from coordinated efforts, says Williams. Williams and his colleagues measure the performance of the dashboard using an F1 score, a statistical measure of accuracy that takes into account the rate of true and false positives. “Usually, our algorithms come in between 85 and 95 per cent,” says Williams. Less than half of hate crimes are reported to the police. According to the Crime Survey for England and Wales, racially and religiously motivated crimes in the two nations spiked after the Brexit vote in 2016, with 5605 crimes reported in July that year, up 44 per cent from the same period in 2015. People with racist views feel emboldened to target others by events like the vote, says Imran Awan at Birmingham City University, UK. The police are often slow in reacting, he says. Awan attributes this to scepticism about the link between online and offline abuse. “The perception is: ‘Do I really need to come out and speak to somebody because they’ve posted a tweet?’.” Hate-speech detection tools that analyse aggregated data may not be able to prevent individual acts of violence, says Timothy Quinn at Hatebase, a firm that provides hate speech resources to law enforcement agencies. Such tools are more useful for governments to identify overall rises in hate speech across a region, giving opportunities to prevent it escalating into violence in the form of riots, for example, he says. ❚ Ornithology Analysis Polio City crows may have high cholesterol thanks to fast food Wild polio virus eradicated in Nigeria, but battle isn’t over yet Jake Buehler Debora MacKenzie The oral polio vaccine has helped wipe out wild polio in Nigeria PIUS UTOMI EKPEI/AFP/GETTY IMAGE CROWS living in urban areas have higher blood cholesterol levels than their rural counterparts. That may be due to the food we leave behind for them to feast on. Crows are “experts at raiding human trash cans and dumpsters”, says Andrea Townsend at Hamilton College in New York. Some of the food they scavenge is fast food, which is often high in cholesterol. Townsend and her colleagues measured cholesterol levels in blood samples taken from 140 American crow (Corvus brachyrhynchos) nestlings in rural, suburban and urban areas in California. They also measured the birds’ body mass and fat reserves, and tracked their survival rates. They found that the more urban the surroundings, the higher the blood cholesterol of the crow nestlings. To see if access to the foods that raise cholesterol in humans were responsible, the researchers ran a “cheeseburger supplementation experiment” where they left cheeseburgers near nests in rural New York. Townsend didn’t have reservations about leaving behind burgers for the nestlings as elevated cholesterol doesn’t appear to affect all species in the same way, and has actually been linked to better body conditions in some animals, she says. The burger-fed rural crows had cholesterol levels that were about 5 per cent higher than nearby crows that weren’t given fast food. Those that ate the burgers had cholesterol levels more similar to crows living in cities (The Condor: Ornithological Applications, doi.org/c9r9). Townsend says these results are consistent with the handful of other studies on cholesterol in animals that live near humans, including foxes, sparrows and even sea turtles living near more densely populated Canary Islands. ❚ NIGERIA has officially wiped out wild polio, after three years without a case caused by the wild polio virus. This is a heartening milestone for a country that nearly derailed the global drive to eradicate the disease after some regions banned vaccination in 2003. But Faisal Shuaib, head of the country’s public health agency, called for “cautious euphoria”. That’s because Nigeria hasn’t wiped out polio. As first revealed by New Scientist in 2000, the live, weakened polio virus used in the vaccine responsible for the breakthrough can spread between people and mutate to a form that can paralyse. It has caused 15 cases of vaccinederived virus infection in Nigeria so far this year. There are ways to stop this happening, but they haven’t been rolled out fast enough, says Michel Zaffran, head of polio eradication at the World Health Organization. The drive to eradicate polio was based on a cheap, effective oral vaccine containing three strains of live, weakened polio virus. The Type 2 strain replicated faster than the others, provoking the most immunity. As a result, wild Type 2 polio has been eradicated worldwide since 1999. The Type 2 vaccine virus is also the strain most likely to mutate to a disease-causing form. In 2018, there were 70 cases of vaccine-derived polio in seven countries, the majority Type 2 viruses. So in 2016, everyone shifted to using “In 2018, there were 70 cases of vaccine-derived polio in seven countries” a live oral vaccine containing only Types 1 and 3. Immunity to those improved, and cases fell. At the same time, children were supposed to get an injected vaccine containing killed versions of all three strains of virus, making them immune to any vaccine-derived virus still circulating. In this way, India eradicated all polio in 2014. But too few children in poorer nations get routine vaccinations, so “there have been more outbreaks of Type 2 vaccine-derived virus than we expected”, says Zaffran. The only way to stop such an outbreak spreading is to give people a live, oral vaccine containing only weakened Type 2. This is because while the injected vaccine will stop people getting infected, once they are infected only the live vaccine will stop them spreading the virus. In an outbreak, 95 per cent or more of people infected don’t have symptoms but spread the virus, so many people must be vaccinated. But the live, Type 2 vaccine also spawns yet more potentially dangerous vaccinederived virus, which can go on to cause more infections if it encounters children who haven’t been immunised against Type 2 with the injected vaccine. Routine vaccination must improve alongside outbreak response, but that is a slow, expensive process and is hampered in many places by unrest or conflict, including in northern Nigeria. That’s not the only problem. Only three companies make the live, Type 2 vaccine, so we could run out. “We have enough to cope now, but there could be a crisis if the outbreaks don’t improve,” says Zaffran. Yet there are ever more people susceptible to vaccinederived Type 2 polio, as wild polio no longer circulates and immunises people, and too few receive the injected vaccine. Polio could roar back worse than ever if it isn’t contained, says Zaffran. ❚ 31 August 2019 | New Scientist | 7 Fieldnotes East Anglia, UK JANE HAMILTON stands next to a model of Dunwich in Suffolk, UK, the “lost city” that was once one of England’s largest ports, but has been largely swallowed by the sea after storms in the 13th and 14th century and years of erosion. She accepts that people will have to retreat in the face of a warming world and rising seas. “It’s natural. It’s like people dying, it does happen,” she says. As a resident of the remaining village, that doesn’t mean she wants to stand back and let it happen. “It’s human nature to preserve your community,” says Hamilton. “I don’t accept: ‘That’s fine, it’s all going to fall in the sea, we’ll all move inland.’ ” Dunwich is one of several communities in East Anglia, an area on England’s east coast, that must decide whether to promote a “managed retreat” inland or to hold the line. In a recent article in Science, researchers argued that adaptation to climate change means, in some places, “the “It’s human nature to preserve your community. I don’t accept: ‘That’s fine, it’s going to fall in the sea’ ” question is no longer if retreat will occur but how, where, and why”. The UN’s Intergovernmental Panel on Climate Change predicts warming will bring a sea level rise of up to a metre by 2100, and more if the Antarctic ice sheet begins its collapse this century. In England, the Environment Agency (EA) has said sea level rise can’t be fought with “limitlessly high walls and barriers” alone. Juliet Blaxland, who lives a few kilometres up the coast from Dunwich near the crumbling cliffs of Easton Bavents, recognises the need to adapt. “In nature, the most successful animals are 8 | New Scientist | 31 August 2019 JASON BYE FOR NEW SCIENTIST Moving away from the coast Rising sea levels mean that a managed retreat for coastal communities is no longer a case of if, but when and how. Adam Vaughan reports not necessarily the biggest and fastest, but the most adaptable to change,” she says. Historically, around a metre of coast was lost each year here, but recently, it has been around 3 metres annually, she says. While Blaxland accepts that her home probably has just a few more years left, neighbouring buildings reveal contrasting attitudes towards coastal erosion. One is the former house of Peter Boggis, dubbed King Canute for building his own coastal defences by the cliffs, in defiance of authorities. Down the road, a pair of holiday homes, the Watch Houses, were built with steel frames so they can be easily moved inland by crane. In the past, the UK government offered money to help people relocate, as well as assisting with planning issues around new homes for them, but no such schemes are active today. “We are very much responding to the climate emergency,” says Julie Foley of the EA. Its policy is to defend the majority of England’s coastline, and moving people in response to climate change is the exception, she says. The EA recently finished the £70 million Ipswich Tidal Barrier in Suffolk, a large “hold the line” defence. More hardware and engineering like this will be needed in the region, says Mark Johnson of the EA, such as an increase in the height of beaches in Norfolk to help protect Bacton Gas Terminal. David Ritchie of East Suffolk Council says managed retreat can be positive, pointing to the Benacre Estate, just north of Easton Bavents, where there are plans to flood 100 hectares with seawater to create an intertidal habitat. In Shotley, near Ipswich, Richard Wrinch stands on the doorstep of his farmhouse, overlooking a glorious vista of fields bordering the river Orwell that flooded during a 2013 storm surge. The farmer has been talking with the EA and others for more More climate change online For more on our warming planet newscientist.com/subject/environment Coasts are in retreat across East Anglia, including here at Happisburgh in Norfolk than a decade about giving up land to the sea. “I have no direct problem with a managed retreat, because that’s what humanity has done for millennia,” says Wrinch. What is missing is clarity from authorities, he says. A glimpse of a possible future for Wrinch lies across the county border in Essex. At Fingringhoe Wick nature reserve, the sea wall was deliberately breached in 2015, so seawater now covers 22 hectares of former farmland. Mark Iley of the Essex Wildlife Trust, which worked with the EA on the scheme, says losing hardwon land is “very controversial”, but that the project has been a roaring success for both human and avian visitors. The motivation was to create salt marsh habitat, which is fast disappearing throughout England. However, the approach could be applied elsewhere if the two challenges – finding funding and willing landowners – are overcome, says Merle Leeds of the EA. ❚ JOBS FOR PEOPLE WHO ARE ASKING THE HOW, WHAT, WHY… Whatever path you choose to take in science career, New Scientist Jobs can help you find your dream job. We have 100’s of jobs in Life Sciences; from Marine Biology, Microbiology, Molecular Biology and many more. Sign up and be the first to apply at: newscientistjobs.com Putting brilliant minds to work @science_jobs | #Sciencejobs News Animals Koala microbiome shift Faecal transplants help the marsupials change their diets KOALAS in Australia may find settling into a new habitat easier after a faecal transplant. In 2013, a population of koalas grew so large that the animals ate enough leaves from their preferred type of eucalyptus tree, the manna gum (Eucalyptus viminalis) to kill many of the trees. This resulted in starvation and the death of more than 70 per cent of the koalas. Surviving animals were moved to a new area, but they had little interest in feeding on a similar tree, the messmate (Eucalyptus obliqua), despite other koalas living off it exclusively. Michaela Blyton at the University of Queensland, Australia, found that giving the relocated koalas a faecal transplant from the local population helped them to adapt. The process changed the koalas’ natural mix of bacteria, which began to resemble that of the donors (Animal Microbiome, doi.org/c9nx). ❚ JOUAN & RIUS/NATUREPL.COM Ruby Prosser Scully Cosmology LIGO could solve space expansion mystery COSMOLOGISTS can’t agree on how fast the universe is expanding because the two methods they use to find out give distinctly different results. Now a third method involving gravitational waves could help break the deadlock. Gravitational waves are the ripples in space-time whose existence was confirmed in 2015 by the Laser Interferometer Gravitational-Wave Observatory (LIGO). They are produced when massive objects like black holes or neutron stars smash together (more on page 13). To calculate the Hubble constant, which quantifies the expansion rate of the universe, astronomers usually look at distant objects and 10 | New Scientist | 31 August 2019 find out two things: how far away they are and their redshift, which is the degree to which the object’s light has stretched as it passed through expanding space on its way towards us. The Hubble constant is usually calculated either by looking at certain supernovae or at the cosmic microwave background, often called the big bang’s afterglow. But these methods result in different numbers. It is possible that this discrepancy is caused by errors, but some astronomers believe that it is evidence of unknown physics. The events that make gravitational waves don’t always produce light. Even if they do, it can be hard to spot. But in 2017, LIGO researchers showed that if they could catch some light from the source of a gravitational wave, they could measure the redshift. The gravitational wave itself gives the distance, so the Hubble constant could be calculated. “The two methods we use to find out how fast the universe is expanding give distinctly different results” Now the LIGO team has extended its work to black hole mergers, which don’t emit light. The group instead used galaxy catalogues to identify the most likely place that the gravitational waves came from. Then they used the galaxy’s redshift in their calculations (arxiv.org/ abs/1908.06060v1). The new method is important because it is independent of the other two, but it can’t yet provide a definitive answer. The 10 detections made so far are too few to provide a precise estimate of the constant. “At the moment, our method is like Switzerland, completely neutral,” says Patricia Schmidt at the University of Birmingham, UK, and a member of the LIGO consortium. As more detections are made, the estimate should get more precise. ❚ Stuart Clark Data privacy Revealing why posts are moderated helps us comply with rules Facebook’s data collection may put gay people at risk Chris Stokel-Walker Chris Stokel-Walker SOCIAL media platforms struggling to tackle the tide of misinformation and unsuitable content could cut its flow by a fifth by better explaining their rules. That is the finding of a large-scale study of 32 million posts on popular discussion site Reddit. On Reddit, volunteer moderators clear forums, called subreddits, of unsuitable or off-topic material. Moderators take different approaches, however. Some explain why they have removed the content, but about 99 per cent simply take it down without explanation. Shagun Jhaver at the Georgia Institute of Technology and his colleagues have found that those who have had their posts removed – with or without explanation – are less likely to continue posting. But those who aren’t provided with a reason why their content was taken down have a higher likelihood of further posts being removed than those who are given an explanation. Another study by the team found that 37 per cent of Reddit users surveyed didn’t understand why their post was removed, and 29 per cent felt frustrated that it had been. The group calculated that if all post removals were accompanied with an explanation, the odds of future removals would drop by 20.8 per cent. The team will present the work at the Conference on Computer-Supported Cooperative Work and Social Computing in Texas in November. While the system works in small communities, it may be hard to scale across a larger site such as YouTube, which has been criticised for its opaque rules on what is acceptable content. “Moderators have to be careful about how they articulate their policies,” says Kat Lo at the University of California, Irvine. “It has to be able to move between many different types of context.” ❚ MILLIONS of gay people living in countries where homosexuality is outlawed could be put at risk by Facebook’s advertising practices. This is because the firm allows advertisers to target people on the basis of their interests, including sexual ones. Ángel Cuevas Rumín at Charles III University of Madrid, Spain, and his colleagues analysed the list of options available for targeting adverts on Facebook. They found that about 2000 of the options would be classed as “sensitive” information under Europe’s recent GDPR data protection law. These include a person’s politics, race or sexuality. Some two-thirds of Facebook users in the 197 countries and states the team looked at were tagged with at least one such preference, accounting for a fifth of the overall population. HOCUS-FOCUS/GETTY Internet In Saudi Arabia, where homosexuality can be punished with death, the team found in February that 540,000 people were labelled as having an interest in homosexuality. The team revisited that number in August and it had nearly doubled to 940,000 people. Overall, Cuevas’s team found that there were more than practice, such information could be used to identify people and collect information on them. For example, an advert directed at a particular group could offer a prize to people if they enter their personal details. Facebook says that just because someone shows an interest in something doesn’t mean they have that attribute. You could like a page about gay men, for example, without being a gay man yourself. people in Saudi Arabia are labelled However, there is likely to be as interested in homosexuality overlap between the two groups. “The interest targeting 4.2 million people tagged as options we allow in ads reflect interested in homosexuality people’s interest in topics, not living in countries where personal attributes,” Facebook homosexuality is illegal. told New Scientist. “People can’t These people could be targeted discriminate by excluding using Facebook’s ad tools (arxiv. interests such as homosexuality org/abs/1907.10672). when they build an ad.” The firm While there is no suggestion says it recently removed more that anyone has been identified than 5000 targeting options. or killed as a result of this Collecting such data is a legal grey area. In Europe, there are stronger legal protections for sensitive data than there are for other types of personal data. However, data protection experts are torn over whether Facebook is breaking any laws. “Facebook is in the wrong for sure, as far as EU data protection law is concerned,” says Ed Boal at Stephenson Law in Bristol, UK. Sandra Wachter at the Oxford Internet Institute, UK, isn’t so sure. “If the argument being made is nobody is inferring sexual orientation but assuming an interest in sexual orientation, that brings us to an unclear legal perspective,” she says. “We need to broaden data protection in a more sensible and holistic way.” ❚ 940,000 If you “Like” a Facebook page, the data is used to record your interests 31 August 2019 | New Scientist | 11 News Cryptography Quantum teleportation win QUANTUM teleportation has made a leap in sophistication. Physicists have teleported more information at once than has ever previously been possible, paving the way for a global quantum internet that would be extremely secure from hacking. This isn’t teleportation as you might imagine it from science fiction. Rather than transporting matter through space, it involves moving information related to the quantum state of a particle. Previously, we have only been able to teleport quantum bits, or qubits, the simplest unit of quantum information in which a particle can be in two states at once. For instance, a photon that is simultaneously vertically and horizontally polarised would be a qubit. Now Jian-Wei Pan at the University of Science and Technology of China and Anton Zeilinger at the University of Vienna in Austria and their colleagues have teleported a more complicated unit of quantum information called a qutrit for the first time. If a qubit can be considered two-dimensional, a qutrit is three-dimensional: the photon is polarised in three perpendicular directions. “The higher the dimensions of your quantum system, the more secure you can ensure your communication is and the more information you can encode,” says Ciarán Lee at University College London. “But going from a qubit to a qutrit is especially difficult: the tricks you use for qubits have to do with a nice symmetry that qutrits don’t have.” To teleport a qubit, you begin with three particles. One is the qubit whose information you want to teleport. The other two are a pair of particles that have been entangled in such a way 12 | New Scientist | 31 August 2019 ELLA MARU STUDIO/SCIENCE PHOTO LIBRARY Physicists have used the rules of quantum entanglement to teleport a richer package of information than ever before, reports Leah Crane that making a measurement on one will affect the result of a measurement made on the other. Now imagine two people, traditionally called Alice and Bob. Alice has the qubit and one of the pair of entangled particles. Bob has the other particle in the pair. If Alice wants to send the qubit’s “Passing messages through quantum entanglement would be a very secure means of encryption” information to Bob, she performs a special kind of measurement on both her particle and the qubit. Going through this process means that Alice’s particle is now entangled with the qubit, as well as Bob’s particle. Because of all this entanglement, Alice’s measurement forces Bob’s particle into one of four possible states. He can find out which by making a measurement. The results of Alice’s measurement – which she can send to Bob using non-quantum methods, such as an email – lets him determine how the measured state of his particle is related to that of the original qubit. Once he knows that, he can reconstruct the information from the original qubit. Its information has been teleported. Qutrits are a level up in difficulty because it is much harder for Alice to perform her measurement and entangle her particle with the qutrit. The researchers got around this by adding another particle to the system so Alice is measuring three particles instead of two (Physical Review Letters, doi.org/c9ns). As a result, her measurements contain more information, which she sends to Bob, allowing him to reconstruct the qutrit. The researchers could teleport qutrits with 75 per cent fidelity, meaning Bob’s qutrit was 75 per cent similar to Alice’s original. That may not seem high, Love quantum theory? More entanglement and weirdness online newscientist.com/article-topic/quantum-science Teleportation depends on spooky quantum connections but the highest fidelity possible if the quantum entanglement had failed is 50 per cent. “Seventy-five per cent is probably not good enough to start communicating in this way with much accuracy, but this is early days,” says Lee. The researchers claim that their method could be used to teleport even larger packets of information with higher fidelity. If that works out, it would be a further step towards quantum communication systems. Passing messages using quantum entanglement would be far more secure than current encryption methods. Quantum teleportation could enable information to be passed over long distances by secure quantum networks, says Lee. “The ability to teleport a high-dimensional system is going to be one of the bedrocks on which a future quantum internet is built.” ❚ Neuroscience Tests at 3 years old could predict brain ageing in later life Jessica Hamzelou things like cholesterol and blood sugar levels to estimate the biological age of the volunteers’ bodies. They found that this was loosely linked to brain age, but not totally. “There are some people who have a very advanced brain age whose bodies seem to be ageing slowly, and vice versa,” says Elliott. However, the team found that those who had the highest scores on cognitive tests when Lower stress levels and exercise may help your brain stay young they were 3 years old went on to have the youngest-looking brains (bioRxiv, doi.org/c9ng). This suggests we might be able to tell who is at risk of accelerated brain ageing early in life, says Elliott. He hopes that predicting brain ageing earlier in life could allow treatments for conditions like dementia to be started sooner. This means they might have a better chance of working. James Cole at King’s College London cautions that it will be difficult to make predictions based on a 3-year-old’s test results. “Acceleration or delay could be positive or negative,” says Cole. “If a 60-year-old has a brain that looks 70, that’s bad, but if a 3-yearold has a brain that looks 5, that might be a good thing.” The team also asked other researchers to guess how old the volunteers were based on photos of their faces. Again, the responses varied hugely, with estimates coming in 20 years above and below their actual age. Those who looked older also had older brain ages. “It suggests that the outward signs of ageing are reflected by the internal signs of ageing,” says Cole. That doesn’t mean that all olderlooking individuals will be on their way to dementia, says Elliott. We don’t yet have a way to treat brain ageing, but given the known benefits to the brain of healthy eating and exercise, these aren’t a bad place to start. “Ageing is a complex interaction of genes and environment,” says Cole. “The environmental factors are likely to be things like stress levels, diet, how much physical exercise people get and how much they use their brains,” he says. ❚ they had seen their first black hole and neutron star merger, only for the observation to be chalked off due to the high possibility the signal was background noise from Earth. This time, researchers are almost certain the signal came from beyond Earth. Researchers around the globe are now running the numbers to confirm the identity of the two objects involved. Given its size, researchers agree the larger is a black hole. Based on initial estimates of its mass, the smaller is probably a neutron star. “But there is the remote possibility it could actually be a very light black hole,” says Scott. If that proves to be the case, it would be by far the lightest black hole ever observed. “We have to look at the signal to see if we can confirm it is behaving like a neutron star in the in-spiral,” says Scott. Ticking off the final of the three types of event doesn’t mean LIGO will be powered down, however. “That’s just the end of the beginning,” says Scott. ❚ James Mitchell Crow SALLY ANSCOMBE/GETTY YOUR brain isn’t necessarily the same age as the rest of you. Now, it may be possible to predict how quickly a person’s brain will age throughout life based on tests taken when they are 3 years old. A person’s biological age may be a better indicator of their health than their chronological age. Brain age can be measured using brain scans and machine learning to determine if a person’s brain looks older or younger than the average healthy brain for people of the same age. To find out if brain age might reveal anything about a person’s health in midlife, Max Elliott at Duke University in North Carolina and his colleagues assessed the brains of 869 adults in New Zealand who have undergone regular medical and cognitive testing since they were 3 years old. When the volunteers, all aged between 43 and 46, underwent MRI brain scans, the team found that their brain ages ranged from 23 to 71. Those with older brain ages performed worse on tests of cognition, memory and IQ. The researchers also measured Space A black hole has been seen eating a neutron star ALMOST 900 million years ago, two objects – one a black hole, the other almost certainly a neutron star – slammed together with incredible force, sending shock waves through space-time. These gravitational waves have now washed over Earth. Last week, scientists from the Laser Interferometer Gravitational-Wave Observatory said the waves were picked up by LIGO’s detectors in the US and by Italy’s Virgo detector. “We’re very confident that we’ve just detected a black hole gobbling up a neutron star,” says Susan Scott, a theoretical physicist at the Australian National University in Canberra and part of the LIGO collaboration. If confirmed, the observation would complete the trifecta of cataclysmic events researchers had hoped to detect when LIGO was first proposed: the collision of two black holes; the collision of neutron stars in a binary system; and the merger of a black hole and a neutron star. In April, LIGO researchers thought 900 m Approximate number of years since the collision spotted by LIGO 31 August 2019 | New Scientist | 13 News Briefing Mental health Earth science Why is pollution linked to schizophrenia and depression? Volcano that led to little ice age identified Chris Baraniuk What has the latest study found? Analysing data from 151 million people in the US and 1.4 million people in Denmark, researchers discovered a strong correlation between poor air quality and higher rates of bipolar disorder, schizophrenia, personality disorders and major depression (PLoS Biology, doi.org/gf6t7f). This suggests there is a link, but not necessarily that pollution is causing these conditions. How strong is the link? When the researchers looked at health insurance claims in the US, they found that the strongest predictor of being diagnosed with bipolar disorder (after ethnicity) was air quality. Previous studies have unearthed a correlation in the UK between polluted areas and teenagers reporting psychotic experiences, and local air pollution and psychiatric disorders in Swedish children. How good is the evidence? “We don’t really know very much overall. We’ve only got a handful of studies and most have methodological problems,” says Helen Fisher of King’s College London, who worked on the UK teenager study. One problem is a lack of data on what an individual’s true exposure to air pollution has been, with some research looking at city-wide air quality BILL BACHMANN/ALAMY STOCK PHOTO A NEW study has added to the mounting evidence suggesting air pollution is linked to mental health conditions. But it isn’t clear yet how – or if – pollution may be affecting our brains. Busy traffic in Copenhagen, Denmark measurements rather than specific addresses. That is a big weakness, given we know air pollution exposure can vary significantly from one street to the next. In the new study, exposure in the US was mapped at county level, administrative areas that can cover thousands of square kilometres. What else could explain the associations between dirty air and psychiatric conditions? The study tried to take into account confounding factors where figures were available, including income, ethnicity and population density. But an obvious factor that could be linked to both mental health and pollution is traffic noise. This is known to increase stress and disrupt sleep, which are both linked to mental ill health. In what ways could pollution affect our brains? Some of the smallest pollution More mental health news online The latest research on depression and other conditions newscientist.com/article-topic/mental-health 14 | New Scientist | 31 August 2019 particles can pass through the blood-brain barrier, potentially affecting the brain. Air pollution is known to cause inflammation in the body, which may ignite the brain’s stress response. Or perhaps pollution can cause epigenetic changes that affect the levels of signalling chemicals in the brain. But these are only tentative ideas. “Air quality was a strong predictor of being diagnosed with bipolar disorder” Why does it matter if air quality affects our brains? Shouldn’t we care because of the known physical effects it has anyway? Stronger evidence of a link to mental health might not have a huge impact on policy because the case for action on air pollution – such as it shortening lives through lung and heart problems – is strong. But if dirty air was found to cause mental illness, it would “open new avenues to the prevention and treatment of mental conditions”, John Ioannidis at Stanford University in California wrote in a commentary in PLoS Biology. ❚ Adam Vaughan A MINI ice age that lasted for 125 years began in the middle of the 6th century, helping to plunge the world into an era of chaos. One of the key events behind it was the massive eruption of a volcano somewhere in the southern hemisphere. Now we may know when and where it happened. Huge eruptions fling so much ash and debris into the atmosphere that sunlight is partially blocked. This can cool Earth and encourage more ice to form at the poles, which reflects more sunlight, further cooling the planet. It has long been thought that the eruptions of volcanoes between AD 536 and 547 kick-started what is known as the Late Antique Little Ice Age. Robert Dull at California Lutheran University and his colleagues have now shown that the second of two big eruptions during this time appears to have occurred at the Ilopango volcano in El Salvador. The team found the remains of three trees that “witnessed” this event. Two of these were killed by the volcanic activity. Radiocarbon dating on multiple tree rings inside the trunks revealed their age – the trees died between AD 503 and 545. Evidence from ash deposits in nearby soil also helped to confirm that a gigantic eruption happened around this time, most likely in late AD 539 or 540 (Quaternary Science Reviews, doi.org/c9nk). An earlier big eruption is thought to have occurred in AD 536, but researchers haven’t yet managed to identify which volcano was involved. “I think the Late Antique Little Ice Age was started by these eruptions here and prolonged by others,” says Michael Sigl at the University of Bern in Switzerland. The final proof that would tie Ilopango to the AD 540 eruption would be to find debris from it in Antarctic ice cores from that time, he says. ❚ NEW DATE! Our popular event is coming to Boston … INSTANT EXPERT: MYSTERIES OF THE MIND November 23, 2019 District Hall, Boston You’re in possession of one of the most complex and incredible objects in the known universe: the human brain. How does a 1.4 kilogram tangle of nerve cells allow you to sense, understand and change the world? Discover why this is the most exciting time in the history of brain science with six experts working at the forefront of neuroscience, genetics and psychiatry. TOPICS COVERED WILL INCLUDE: Intelligence Consciousness Memory Plus much more Reserve your place today and view our speaker line-up newscientist.com/mindevent-boston News In brief Bacteria How airborne microbes conquered Mars-like desert APEXPHOTOS/GETTY MICROORGANISMS fly into the Atacama desert on grains of dust carried by the wind, which may be how they first colonised the desert. The finding suggests that if there are microbes on Mars, they could be carried around the planet by global dust storms, says Armando Azua-Bustos at the Centre of Astrobiology in Madrid, Spain. The Atacama in South America is one of Earth’s driest places, with soils so parched they resemble those of Mars. Some Atacama microbes survive even in the driest spots, but questions remain over how they got there. Azua-Bustos and his colleagues suspected microorganisms arrived on dust carried by afternoon winds that blow in from the Pacific. To find out, they set out Petri dishes filled with nutrients in lines stretching Biocomputing GENE editing can turn living cells into minicomputers that can record data and could track what happens inside the body. DNA computers have been around since the 1990s, when researchers created DNA able to perform basic computer functions. Instead of storing information as 0s and 1s like digital computers do, these computers store information in A, C, G and T, DNA’s molecular code. One problem is that this information doesn’t change during a cell’s life, making DNA computers very slow. Now Fahim Farzadfard at the Massachusetts Institute of Technology and his colleagues have created a technique that uses DNA editing to speed up the process. They call their system DOMINO, for DNA-based Ordered Memory and Iteration Network 16 | New Scientist | 31 August 2019 Asteroids Operator. It is designed to respond to various biological cues, such as small molecules or light, and builds on CRISPR gene-editing techniques. Current technologies used to edit genes in cells or organisms are limited. Their capacity to store data stops after one or two molecular events. In contrast, DOMINO can be programmed to edit DNA after complicated chains of events, allowing it to encode more information quickly. One application for the system could be to monitor sugars, by programming it to respond to lactose for example. When a bacteria with the system encounters lactose, DOMINO would make changes to its DNA (Molecular Cell, doi.org/c9n3). The history of events are then stamped onto the DNA in the form of unique mutational signatures that don’t fade over time even after the cues, in this case lactose, fade away, says Farzadfard. ❚ Ruby Prosser Scully Space rock Ryugu is a dustless oddity THE MOST detailed pictures yet of the asteroid Ryugu have revealed something odd: a lack of dust. After arriving in 2018, Japan’s Hayabusa-2 spacecraft dropped three landers and took a sample from Ryugu’s surface. Now, pictures from one of the landers have revealed more details about the composition of the asteroid. Ralf Jaumann at the German Aerospace Centre’s Institute of AKIHIRO IKESHITA/JAXA Cells could become computers in body from the coast to the desert interior. Any microbes flying in would land in them. They found 28 species growing in the dishes and extracted DNA from several more that landed but didn’t grow. The microbes came from near the coast (Scientific Reports, doi.org/c9pc). Oceanobacillus oncorhynchi is one of them. It lives in tidal pools. Because the pools evaporate in the heat of the day, it can survive being dried out for hours – giving it a chance of surviving the Atacama. Azua-Bustos says such microbes may have been the first to colonise the desert. Mars is prone to dust storms, so if there is any microbial life there it could be dispersed on dust grains. And if life can be moved around Mars, contamination from our probes could spread fast, he says. ❚ Michael Marshall Planetary Science in Berlin and his colleagues have analysed the images. They were surprised to see the surface of Ryugu doesn’t have a layer of dust (Science, DOI: 10.1126/science.aaw8627). This is strange because dust is expected to accumulate through collisions in space. One explanation could be that fine dust becomes charged due to solar radiation and gets removed by electrical forces, says Jaumann. Another is that the release of volatile gases from the surface might have blown the dust away. Or maybe, if Ryugu shakes as it travels through space, the dust could have gradually settled in the interior of the asteroid, meaning we can’t see it. The pictures also revealed details of rock texture on the surface. The images show there are two kinds of rock on Ryugu’s outer layer, dark and rough or bright and smooth, and they both take up an equal share of the surface. ❚ Abigail Beall New Scientist Daily Get the latest scientific discoveries in your inbox newscientist.com/sign-up Chemistry Really brief This material will self-destruct CARLO PREARO/EYEEM/GETTY AGENTS might soon be able to drop behind enemy lines and leave no trace, thanks to a material that can be made into gliders or parachutes but that disintegrates when exposed to heat or light. The self-destructing polymer, initially designed for use in battlefield sensors, is the work of Paul Kohl at the Georgia Institute of Technology and his colleagues. They began with polymers that have a low ceiling temperature, Honey can tell us all about lead pollution Bees pick up pollution as they fly around and some of it ends up in their honey, although it is still safe to eat. Kate Smith at the University of British Columbia in Canada found that analysing honey is as good a way to check lead levels as using soil or air samples. It could be used to monitor remote areas. the point at which the key bonds in a material begin to break. Lots of polymers slowly decompose when they reach this temperature because many bonds have to be severed. But Kohl designed his material so that as soon as one bond breaks, the whole thing unzips. It is made from a chemical called an aldehyde with various additives that can either make the material rigid for use in a glider or sensor, or flexible to make a fabric. Sunlight can trigger the disintegration. Or, in true spy style, a small light-emitting diode Demographics Technology App designed to spot winter vomiting bug Blood pressure linked to brain size People with high blood pressure in their 40s seem to have smaller brains at age 70. The findings, from a group of 500 people aged between 69 and 71, hints that looking after your health may help prevent some forms of dementia (The Lancet Neurology, doi.org/c9nm). VISUAL CHINA GROUP VIA GETTY Time to get up and move around a bit Sitting for nine and a half hours or more a day is associated with a higher risk of early death in middle aged and older people, according to a review of data from over 36,000 individuals. The study found that any level of physical activity, regardless of intensity, is linked to a lower risk of premature death (BMJ, doi.org/c9nw). can be put in a device to trigger it to self-destruct on demand. When the substance falls apart, all that is left is a residue and a faint smell. Kohl and his team have made a glider with a 2-metre wingspan, and he says they can make 5 kilograms of the polymer at a time. The work was presented at a meeting of the American Chemical Society in California. Marek Urban at Clemson University in South Carolina worries that the residue could be toxic. Kohl says he has tested it on plants, which survived. ❚ Chelsea Whyte Two-child policy in China sees millions more babies born A CHINESE government policy allowing all couples to have two children led to an extra 5.4 million births in its first 18 months. China’s universal two-child policy, announced in October 2015, was designed to boost the country’s stagnating population growth. It targeted 90 million women of reproductive age who already had at least one child – 60 per cent of these women were older than 35. Susan Hellerstein at Harvard University and her team looked at data on 67.8 million births in most of China from January 2014 to December 2017. They measured birth rates from July 2016 to December 2017, covering the first 18 months after the policy began. The team compared these with baseline birth rates up to the end of June 2016, nine months after the October 2015 announcement. In the 18-month period, there were 5.4 million additional births to women who already had one or more children (BMJ, doi.org/c9n2). Despite the national increase in births, the total probably fell short of the government’s annual target of 20 million. China’s one-child policy, introduced in 1979, was scrapped amid concerns about an ageing population and shrinking workforce. ❚ Donna Lu A SMARTPHONE app can detect signs of norovirus, the most common cause of gastroenteritis. Jeong-Yeol Yoon and his team at the University of Arizona used a phone with an add-on microscope and a light source to detect low levels of norovirus in water. Their technique can spot as little as 10 attograms (10−18 grams) of norovirus per millilitre, six orders of magnitude better than other portable detectors, says Yoon. That is important, as even tiny amounts of norovirus can trigger illness. Also known as the winter vomiting bug, norovirus is notorious for causing vomiting and diarrhoea in crowded situations, such as on cruise ships. At the heart of the team’s test is a paper chip that contains tiny beads of fluorescent polystyrene. These beads contain antibodies against norovirus. When virus is present, it binds to clumps of beads. Under the light, these clumps fluoresce. Analysis via the phone microscope reveals the level of norovirus present. The team is using it to test water supplies. A diagnostic version for checking stool samples is planned. The research was presented at an American Chemical Society meeting in California. ❚ DL 31 August 2019 | New Scientist | 17 News Insight Wildfires Dawn of the pyrocene 20 | New Scientist | 31 August 2019 decades. This is probably because of the way we are managing forests to reduce the risk of fire. Surprising as it may seem, this year isn’t that special when it comes to fire, either, globally speaking. The European Union’s Copernicus Atmosphere Monitoring Service (CAMS) says that some 3500 megatonnes of carbon dioxide were emitted from wildfires in the first half of this year. At a global level, that makes 2019 distinctly middling compared with the past 16 years. The fires in the north, however, are exceptional. “This year has been unprecedented for wildfires in the Arctic,” says Carly Phillips at the Union of Concerned Scientists and Woods Hole Research Centre in Massachusetts. About 173 megatonnes of CO2 have been emitted from Arctic fires so far this year, according to CAMS, which is a record amount (see chart, below). Russia has been hit hardest, with more than 13 million hectares affected and smoke hazes reported in cities. So why the surge in Arctic fires? The region is effectively stuffed with fuel: huge swathes of forest and peat. Most of this doesn’t normally burn because it is cold and wet. But this year, maximum 200 2019 data is up to 18 August 150 100 50 0 2005 2010 2015 SOURCE: COPERNICUS ATMOSPHERE MONITORING SERVICE The amount of carbon dioxide emitted by wildfires in the Arctic is a proxy for how big the blazes are. The fires in 2019 are the largest for at least 16 years Annual CO2 emissions (megatonnes) DEVASTATING wildfires across the world have made front-page news in recent times, from last year’s deadly blazes in Greece to the widespread property destruction in Canada three years ago. One place you might not expect to be burning, however, is the Arctic. Yet as New Scientist went to press, millions of hectares of land in the Arctic were ablaze. Fire is a natural part of the ecology of the vast boreal forests that girdle Earth in northern latitudes. But the amount of vegetation that has been on fire across Alaska, Canada and Russia since June is highly unusual. Even Greenland, four-fifths of which is covered in ice, has seen fires. The impacts on human health and the environment are coming into focus – and they are worrying. Is there anything we can do? This year has already seen striking fires around the world, including in places not usually known for them, such as the UK (see “Fires in February”, right). In Indonesia, where fires are often started to clear areas for oil-palm plantations, the fire season may prove to be as bad as that of 2015, when blazes there created a plume of smoke that extended halfway around the planet. Brazil’s space agency has reported more than 75,000 fires in the Amazon this year, a record number. A surprising number of crop fires have hit the Netherlands, Germany and Luxembourg, says Cathelijne Stoof at Wageningen University in the Netherlands. You would be forgiven for thinking that fires are on the rise globally. In fact, the evidence doesn’t bear that out. For example, a 2017 study led by Niels Andela at NASA used satellite images to show that the amount of land being burned worldwide has actually decreased in recent CONTAINS MODIFIED COPERNICUS SENTINEL DATA [2019]/SENTINEL HUB/PIERRE MARKUSE Wildfires raging in the normally wet Arctic could spur a powerful feedback loop releasing yet more emissions, discovers Adam Vaughan 2019 Siberia has been hit hard by wildfires, as this satellite image shows temperature records have tumbled, making it warm and dry enough for blazes. “The north is a big tinder box, but it’s been limited from burning by the climate,” says Merritt Turetsky at the University of Guelph in Canada. “If you remove those climatic constraints, all those fuels are ready to go.” Climate change could also be contributing to the lightning strikes that usually ignite the fires. More lightning is linked to rising surface temperatures. “Hot weather is making the Arctic more thunderstormy than normal,” says Rod Taylor of the World Resources Institute in Washington DC. Most of the fires are in remote regions, but that doesn’t mean people are escaping the effects. “What happens in the Arctic doesn’t stay in the Arctic. Pollution can carry thousands of miles away,” says Elizabeth Hoy at NASA. The agency has tracked smoke from the fires in Siberia reaching the US and Canada. That pollution can combine with a city’s local Working hypothesis More Insight online Sorting the week’s supernovae from the absolute zeros Russia’s Aerial Forest Protection Service battled fires earlier this month away an insulating layer that helps maintain permafrost – ground that is normally frozen. This makes it more likely that the permafrost could thaw and release even more CO2. Permafrost thaws discharge not just CO2, but also the more powerful greenhouse gas methane. The potential positive feedback doesn’t end there. Researchers at CAMS have already used satellites to track soot from this year’s northern Russia fires. Some landed on ice in Greenland. That matters because studies have shown that soot can alter the reflectivity of ice, making it absorb more of the sun’s energy and heat up. The remote nature and sheer scale of the Arctic means there isn’t a lot that firefighters can do about these fires. Russia had to send in the army, planes and Fires in February A WAVE of warm weather hit the UK in February and three huge fires broke out in different parts of the country. In fact, the period between June 2018 and June 2019 was a “really crazy year” for wildfires, says Thomas Smith at the London School of Economics. The UK has had 95 large wildfires in 2019 already. In the Arctic, it is often forests that burn (see main story). In the UK, peat and heathland blazes are the main problem. “There is potential once the fire is in the peat of it being protracted. It’s a more difficult fire to deal with,” says Paul Hedley at the National Fire Chiefs Council. Since the 2018 moorland fires near Manchester, the UK’s worst in decades, the country’s fire and rescue service has trained 35 staff nationally as wildfire tactical advisers, to pool expertise and aid coordination. Despite this, wildfires are a growing burden. “There is no way of getting around it, it is a real challenge for us,” says Hedley. helicopters to tackle flames in some areas. “Large-scale intervention is very costly and not very effective for large and remote fires,” says Cristina Santín at Swansea University, UK. Russian authorities have tried seeding clouds to induce rain. The idea is that planes spray chemicals such as silver iodide in an effort to enhance the rate of ice crystal formation in the atmosphere, producing more clouds, but there is no evidence this is effective. Today, firefighters’ priority is to protect life and property. Turetsky ▲ Kakapo The birds are back in town. For the first time in 70 years, the number of kakapos, New Zealand’s giant parrots, has hit 200. ▲ Chunky chips Ever wished microchips were larger? Then Cerebras Systems’s (macro) chip could be for you. It is as big as an iPad and will be used for AI. 173 ▼ Fogcam Farewell to the world’s oldest running webcam. Fogcam had recorded weather in San Francisco since 1994, but will be shut down because its owners say there are no good places to put it. megatonnes of CO2 emitted from fires in the Arctic so far in 2019 says that could in future be extended to protecting rich stores of carbon in the Arctic. “It might be governments come together to protect certain areas where we understand where the old carbon is,” she says. The other thing we can do is to reduce CO2 emissions. In the future, hotter, drier conditions in the Arctic will set the stage for more blazes. A recent report on land use by the UN’s climate science panel warned as much. Stephen Pyne, who studies the history of fire at Arizona State University, says we are entering the “age of the pyrocene”. One crumb of comfort is that the feedback loop can’t continue forever. Once forest is burned, it can’t keep burning. And smoke from northern fires has a modest cooling effect, reflecting some of the sun’s energy. In the meantime, however, the Arctic is still on fire. ❚ Read about geoengineering efforts to refreeze the Arctic on page 38 ▼ Cruelty YouTube removed videos of robots fighting each other for defying animal (not android) cruelty rules. ▼ Practice A study found that good violinists practise just as much as even better ones, suggesting the phrase practice makes perfect is far from perfect after all. BY_NICHOLAS/GETTY; TOP: ROSS HENRY/ALAMY fumes to turn air quality from average to poor, potentially causing respiratory problems for young, old and other vulnerable people. The health costs aren’t just physical. Turetsky says that in Yellowknife, the capital of the Northwest Territories in Canada, doctors have reported increasing rates of hospital admissions for post-traumatic stress disorder during and following wildfires. At a workshop she ran in the city, many people reported what they called eco anxiety. “A lot of these people didn’t experience the fires directly, but they know it’s going to come back,” says Turetsky. The effect on the climate could be more serious still. The problem isn’t simply that fires release a lot of CO2. This will exacerbate global warming, and Arctic wildfires have released about the same amount of CO2 this year as the Netherlands does in a year. “For me what is far more insidious is the long-term climate impact,” says Phillips. Her worry is the prospect of a harmful positive feedback loop. Fires burn off vegetation, stripping TASS VIA GETTY Your guide to a rapidly changing world newscientist.com/insight 31 August 2019 | New Scientist | 21 Discovery Tours USA Cruise Hawaii with Richard Dawkins Departing: 9 days from $10,365 22 October 2020 Join evolutionary biologist and highly regarded author Richard Dawkins on a boutique yacht Tour highlights include: k Evening seminars with Richard Dawkins k 7 nights aboard the Safari Explorer yacht - small enough to reach places that other vessels cannot k Explore Big Island’s living vocanic landscape and misty forests k Visit secluded bays and experience a large array of wildlife k Immersive exploration by boat, trekking, k A thrilling night-time snorkelling adventure seeking giant manta rays k Enjoy the cultural treasure of a ‘pā‘ina feast and discover the history of this ancient homeland k A day in Kailua-Kona, where the slopes of the Hualalai volcano meet the ocean k Maui and Big Island plus the lesser visited islands of Molokai and Lanai snorkelling and private coach To give guests the best possible experience there is a 2:1 guest-to-crew ratio and we only have 32 places available, so please get in touch early to ensure you don’t miss out. To book call +1 516 226 7917 (UK hours Mon to Thu 9-5:30pm, Fri 9-5pm GMT) Or email newscientist@steppestravel.com newscientist.com/tours In partnership with Steppes Travel Views The columnist James Wong delves into claims that fruit is bad for you p24 Letters Using biomass to make fuel is a criminal waste p26 Aperture Three years’ worth of shipping glints in the English Channel p28 Culture How the psychology of happiness feeds a vast industry p30 Culture columnist Helen Marshall on poking fun at business culture p32 Comment The right (not) to know Genetic medicine challenges age-old notions of who should share in a patient’s diagnosis, says Laura Spinney JOSIE FORD O NCE upon a time, a doctor’s consulting room was as safe as a confessional. You could say what you liked confident that, barring very exceptional circumstances, it would go no further. No more. Two legal cases, one in Germany and one still ongoing in the UK, show how the limits of patient confidentiality are being tested, and how this challenges longestablished medical norms. At issue is how to define a patient in an era of genetic testing. If a test shows that I carry a disease-causing gene, that may be relevant to other members of my family. If I refuse to tell them, should my doctor? That is the nub of a trial coming up at the High Court in London in November, in which a woman is suing the hospital that diagnosed her father with Huntington’s disease for not informing her. Huntington’s is a fatal, incurable neurodegenerative disorder caused by a mutation in a single gene. Every child of an affected parent has a 50 per cent chance of inheriting the mutation. The woman argues that, had she known her father’s diagnosis, she wouldn’t have given birth to her daughter, who is now herself at risk of Huntington’s. Currently, in the UK as in many other countries, doctors are legally obliged to respect the confidentiality of patients unless they consent to their information being shared. Guidelines issued by professional organisations such as the Royal College of Physicians do acknowledge that situations can arise where a doctor has a duty of disclosure to third parties even in the absence of consent – notably when not sharing information could result in death or serious harm. The High Court trial will test whether that duty of disclosure should also be recognised in law. That could bring some much needed clarity to the area, but also create new problems. What if I test positive for a disease-causing gene variant and my family members, who didn’t consent to be tested themselves, don’t want to know they are at risk? This question was raised by a German case in which a woman sued a doctor for telling her that her ex-husband had Huntington’s, meaning that their two children were at risk. The doctor acted with the consent of his patient, the ex-husband, but the woman’s lawyers argued that the information was useless to her because the condition can’t be cured and the children were too young to be tested anyway. Knowing her ex-husband’s diagnosis without being able to act on it, the woman claimed, had sent her into a reactive depression and left her unable to work. The German case wound its way through several courts before a final decision was handed down, in 2014, in favour of the doctor – despite the fact that, unlike in the UK, the right not to know is legally protected in Germany, with respect to genetic information. Balancing these various rights isn’t easy. Huntington’s is a clearcut case, medically: if you have the mutation, you will develop the disease, assuming you live long enough. That is unusual. In most cases, a gene test is likely to reveal only an increased risk of disease. The real problem is that the law is black-and-white, while predictive medicine is all about grey. ❚ Laura Spinney is a writer and science journalist based in Paris. Follow her @lfspinney 31 August 2019 | New Scientist | 23 Views Columnist #FactsMatter Now that’s fruitloopery Ever heard the one about how zoos stopping monkeys eating bananas tells us that fruit isn’t good for us? Pull the other one, says James Wong I James Wong is a botanist and science writer, with a particular interest in food crops, conservation and the environment. Trained at the Royal Botanic Gardens, Kew, he shares his tiny London flat with more than 500 houseplants. You can follow him on Twitter and Instagram @botanygeek James’s week What I’m reading “Transforming the Nutrition of Zoo Primates (or How We Became Known as Loris Man and That Evil Banana Woman)”. An excellent chapter by Amy Plowman and Francis Cabana from the book Captive Care and Management, Part II What I’m watching The TV adaptation of the film What We Do in the Shadows. I’m a total geek even outside work. This column appears monthly. Up next week: Chanda Prescod-Weinstein 24 | New Scientist | 31 August 2019 AHTENG/GETTY What I’m working on Lots more writing and radio projects, and I am filming part of a new TV documentary. F YOU have ever delved into the world of online diet advice, you might have heard the claim that modern fruit is so filled with sugar that it is unsafe for zoo animals. It might have come with links to media reports with headlines like “Zoo bans monkeys from eating bananas”. The claim that fruit is no longer a healthy part of the diet – for humans as well as animals – has gathered thousands of likes and shares from low-carb devotees around the world. But how good is the evidence behind these claims? As a botanist who knows rather a lot about fruit, but very little about monkeys, I decided to go straight to the source, and talk to the zoologist whose work first spurred these stories. Amy Plowman is director of living collections at Paignton Zoo in Devon, UK, and has done pioneering research on the diets of non-human primates in captivity. She observed that the food given to zoo monkeys was often a poor reflection of what they ate in the wild. In some zoos, it more closely resembled the food preferences of their human keepers. “We have, whether consciously or unconsciously, assumed that human food is suitable for non-human primates,” she says. In some leading zoos, primate species whose diet in the wild is made up overwhelmingly of leaves are routinely fed chicken, eggs, cheese, yogurt, bread and noodles. This understanding of primate nutrition is, Plowman says, “far removed from reality”. To create a diet as similar to the monkeys’ natural diet as possible, she eliminated energy-dense items such as meat, dairy and grains, and reduced the amount of fruit and some of the more calorific vegetables. The monkeys’ new regime consisted essentially of specialist primate feed pellets, leafy veg and fresh tree leaves. In a very short time, Plowman and her team noticed dramatic improvements in the animals’ health, with reduced obesity, improved dental health and even behavioural improvements. The press enthusiastically reported the story, focusing almost exclusively on the angle of zoo monkeys no longer being fed bananas. When other institutions, such as Melbourne Zoo, started to follow suit, it triggered a further flurry of headlines. These news reports rarely mentioned that many of the “These conclusions require us to ignore one small detail: humans aren’t zoo monkeys” animals involved in these new feeding regimes, such as the red pandas in Melbourne Zoo, are essentially leaf eaters and don’t actually eat much, if any, fruit in their natural habitat anyway. But then, pandas being fed bamboo instead of fruit is less of a story. Those who linked the switch to the benefits of particular diets in humans also failed to point out that the new regime given to these animals involved eliminating all meat and dairy too, and swapping to an essentially 100 per cent leaf diet. Advocates of ultra-low carb and meat-heavy “carnivore” diets for humans were therefore sharing research whose findings were contrary to their claims. What does Plowman think of this interpretation of her findings in zoo animals being used as justification for excluding fruit from human diets? “I wasn’t aware of this and find it very surprising,” she says. “Fruit and non-leafy vegetables have a much lower energy content than most of the foods available to humans, so are a very healthy option for us given most of us consume too much.” Stressing that her work on zoo animals couldn’t be translated to humans, she went on to say that the dietary alterations she made were to replace foods higher in sugar and starch with indigestible fibre, not replace it with fat and protein. There is plenty of evidence, she says, that a switch from starch to fat and protein is “definitely not” a good thing. The evidence suggests she is right. In several exhaustive reviews of the best scientific studies we have to date, higher fruit consumption has been consistently linked to a lower incidence of obesity in humans, as well as a reduced risk of cardiovascular disease and even certain types of cancer. Perhaps more pertinently, if you or I were put on a leaf-only diet we would need to eat more than 300 cups of chopped, raw lettuce a day. That wouldn’t be pretty. We would struggle to get anywhere near enough calories to meet our daily needs, and would quickly succumb to nutrient deficiencies. It seems, much like zookeepers of the past, our close-relatedness to monkeys means many of us, low carb activists included, can’t help but project their needs onto ourselves and vice versa. But to do so requires us to ignore one small detail, which even I as a botanist can confirm: Humans aren’t zoo monkeys. 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Plus Before setting off into the Ulley valley, acclimatise in the stunning high-desert town of Leh at the edge of the Tibetan plateau and discover the 11th century Alchi Monastery To give guests the best possible experience and reduce our impact, we only have 10 places available per tour, so please get in touch early to ensure you don’t miss out. To book call +1 516 226 7603 (UK office Mon to Thu 9-5:30pm Fri 9-5pm GMT) Or email newscientist@steppestravel.com newscientist.com/tours In partnership with Steppes Travel Views Your letters Editor’s pick Using biomass to make fuel is a criminal waste 27 July, p 23 From Fred White, Nottingham, UK Michael Le Page’s article barely scratches the surface of the problems with biofuel policy. Solar energy conversion involving wheat is around 0.06 per cent efficient. That is 1/250th the efficiency of the solar cells that we now see covering agricultural land. This idea takes no account of the energy cost of planting, cultivation, fertilisers, pest and disease control, harvesting, processing and distribution of biofuel. Cover roofs in solar cells and leave the good earth for food and nature reserves. From Maarten van der Burgt, Akersloot, the Netherlands Having worked for many years in the biomass field, I was delighted to read Le Page’s article. Using biomass to produce power or fuel, when it has much more important uses, should be a crime. Politicians seem to believe that because biomass is mostly green it fits into a green future. Of course, it is our only source of renewable carbon. But the waste from sugar, paper and wood processing is more than sufficient to supply carbonbased feedstock for the chemical and plastics industry as well as for some very special fuels. Are ‘septic foci’ returning to haunt and hurt us? 10 August, p 42 From Hazel Russman, London, UK Debora MacKenzie reports work suggesting that the gum disease bacterium Porphyromonas gingivalis is behind a range of diseases. When I was growing up in the 1950s, many believed that decayed teeth served as “septic foci”, spreading disease throughout the body. I remember several advertisements for toothpastes 26 | New Scientist | 31 August 2019 and mouthwashes that played on this fear. Dentists usually removed decaying teeth as a precautionary measure instead of trying to conserve them. Then it was declared that bad teeth were just bad teeth and there was no such thing as a septic focus. The idea dwindled into pseudoscience. Is it back? I was a climate change denier but I got better Letters, 13 July From Bruce Denness, Whitwell, Isle of Wight, UK Lucia Singer refers to her teenage concerns about global warming in the 1980s and the existence even then of deniers, who nowadays attribute the undeniable warming to natural fluctuations. Sadly, I was at the time one of those instinctive deniers. Being professor of ocean engineering at Newcastle University and a reader of voluminous reports on deepsea drilling projects that referred to past climate variability, instead of just ignorantly sniping from the bushes, I set about trying to prove my point. This is how I failed. Among those reports, one interpreted global temperature changes over the past 7 million years from cores taken from the Atlantic seabed. A diagram in it seemed to show a sinusoidal variation with a period of 4.8 million years, and variations with successively smaller amplitudes and periods of 2.4 and 1.2 million years. I was hooked. I discovered hundreds of references to proxy-temperature variations, ranging from billions of years down to the most recent hundred or so years. All showed the same summation of sinusoidal curves with halving period and reducing amplitude. I built a simple model based on those sinusoidal curves (see bit.ly/ Denness). Then I compared it with the temperatures measured since instruments were available. This showed global temperature consistently increasing above the model’s forecast. I could explain the difference only by adding human-made heating – of about 3°C for every doubling of carbon dioxide equivalent. I ate humble pie in 1984 and have remained a convert ever since. In 2009, after several years of global cooling, my model forecast the precise scale of warming in the middle of this decade – and the pause in warming since. It forecasts this to continue until about 2030 with accelerating and unstoppable temperature rise after that. I would be delighted to have my model proved wrong. I don’t want to fry. Looking on the bright side of a large seaweed patch 13 July, p 17 From Paul Whiteley, Bittaford, Devon, UK You report the detection by satellites of a giant seaweed patch stretching from West Africa to the Gulf of Mexico. This should be seen as good news. It is taking up nutrients and fertiliser run-off from the land and turning them, with minerals that are dissolved in seawater, into the best compost and soil conditioner I know of. Farmers in Malta and elsewhere have collected seaweed for centuries in order to create new soil and replenish the old. Farming practices throughout the world tend to result in increased erosion and loss of soil quality. There should be ships gathering up this bounty to replace the tired, mineral-deficient soils being washed into the sea. Not everyone depends on thinking in language Letters, 20 July From Martin Greenwood, Stirling, Western Australia David Werdegar asserts we have an “absolute dependency on the signs and symbols of language”. That is questionable: not everybody thinks in the same way. Composers clearly think in musical terms that are sometimes difficult if not impossible to verbalise. Roger Penrose, in his 1989 book The Emperor’s New Mind, uses his own experience, and that of other distinguished scientists, to argue that much scientific and mathematical thought is non-verbal. More on mapping time and language to space Letters, 27 July From Derek Bolton, Birchgrove, New South Wales, Australia Phil Ball suggests that Mandarin speakers think of the future as down because it matches their direction of writing. Even if such a correlation is found across all writing systems, it could equally be that the mapping of time to space came first. Spatial mappings can arise where there is no writing. The Yupno of Papua New Guinea conceive the future as uphill, while for the Aymara of the Andes it is behind one, with the past in front, perhaps on the basis that the past is known, the future unknown (2 June 2012, p 14). The far right recycles its ideas efficiently 17 August, p 24 From Anthony Wilkins, Ripponden, West Yorkshire, UK I enjoyed Graham Lawton’s article on the exploitation of environmental language by the far right. I take exception, though, to the idea that this has only recently emerged. Far-right politicians have often linked notions of nationhood and the environment. This was particularly evident in the 1930s, when some Nazis in Germany used the idea of a Volk embedded within an environment supposedly peculiar to a particular race. So this is another example of the ability of the far right to do its own dispiriting sort of recycling. I see downsides of drawing water from the desert air 3 August, p 38 From Sam Edge, Ringwood, Hampshire, UK Attempts to draw water from the air, and especially the use of metal organic frameworks with their non-intuitive properties, are interesting. But what is going to happen to flora, fauna and downwind weather patterns if large amounts of moisture are pulled from the atmosphere in already arid environments? Please get in touch if you were on the Maths Bus 3 September 1994, p 6 From Lawrence Sithole, Soweto, South Africa Sue Armstrong reported nearly a quarter of a century ago on the Maths Bus that toured South Africa. Some of your readers were attracted to this educational project and volunteered on and supported the bus. I ask them to get in touch through New Scientist. Some obstacles to building better hearing aids Letters, 27 July From John Woodgate, Rayleigh, Essex, UK Alan Gordon suggests hearing aids should replicate the directionality given by the shape of the ear. Most manufacturers use test equipment called a Head and Torso Simulator. This can be fitted with external ears to test the idea. It ought to work. I haven’t yet tried it myself, but I might be able to in the near future. My guess is that it doesn’t work very well. If it does work, it isn’t easy to see how to make its appearance acceptable, especially as hearing-aid manufacturers try to convince people that the aids should be as near to invisible as possible. This is despite it increasing costs and compromising performance. By the way, I’m nearly 82 and am still able to work on things to help people hear. We are halfway to a carbon sequestration solution Letters, 3 August From Barry Cash, Bristol, UK Butch Dalrymple Smith says we should plant trees and make things out of wood to sequester carbon. We are already doing half the job by farming trees to make paper and chipboard. When we have finished with them we recycle or destroy them. Why not preserve the paper and chipboard as a way of storing carbon? We would need to package it to prevent decomposition. How about baling the paper and then coating it in plastic? We have lots of waste plastic to recycle for that. Slime, slime, glorious healing slug slime 15 June, p 19 From Theo Rances, London, UK Leah Crane reports work on using salamander mucus to help heal wounds. This reminded me of the time my father gashed himself while working on a motorbike engine. As someone whose pharmacy training was interrupted by a spell as ground crew in the air force, he knew a Want to get in touch? Send letters to New Scientist, 25 Bedford Street, London WC2E 9ES or letters@newscientist.com; see terms at newscientist.com/letters remedy used in the 1920s, and dispatched me to find a large slug. This he squeezed to make it exude the slime that he found to be healing for the wound. I have never found the need to repeat this treatment on myself. I am surprised that Harvard Medical School has discovered the same phenomenon in Chinese salamanders. A surprising part of Gaia’s self-correcting strategy 10 August, p 13 From John Entwisle, Leatherhead, Surrey, UK After reading your recent article on the Gaia hypothesis, I wondered whether anyone had considered that the human species may be a solution to one of the biggest threats facing Gaia. It seems that humans have just the right amounts of aggression and intelligence to create things that could alter the trajectory of an incoming asteroid that is capable of causing a mass extinction. The last one of these was quite bad and the next could be worse. It would be a risky strategy on Gaia’s part, but if the species also enables life to be established on a second planet that would improve the long-term odds of life’s survival. Such a cool word deserves to be used 13 July, p 15 From Rick McRae, Canberra, Australia Chelsea Whyte writes of moons ejected from their orbits around exoplanets, called “ploonets”. She mentions the slow drift in our moon’s orbit and the possibility that this might be its fate. Would this make it a “protoploonet”? That is such a cool word that it deserves to be used. For the record ❚ The common name of Protonibea diacanthus is the blackspotted croaker (1 October 2016, p 16). 31 August 2019 | New Scientist | 27 Views Aperture 28 | New Scientist | 31 August 2019 Channel vision Photo European Space Agency THIS is a picture of division, but also connection. Hundreds of radar images taken by the European Space Agency’s twin Copernicus Sentinel-1 satellites from 2016 to 2018 have been combined to give this view of the English Channel. Water deflects the radar pulses, rendering the sea wine-dark. Metallic objects, by contrast, ping the pulses back strongly. Most obviously, that reveals ships as bright dots (though wind farms, a recent addition to the seascape off the UK, are evident, too). Two lines of dots proceed ant-like in their designated lanes. The lower consists of ships bound for ports such as Rotterdam in the Netherlands, Antwerp in Belgium, Hamburg in Germany and Felixstowe in the UK; the upper of ships travelling west to the Atlantic. This was the first such maritime “traffic separation scheme”, introduced to reduce the potential for accidents in 1967. Bright dots of vessels queueing to enter the ports of Southampton in the UK and Le Havre in France are also visible to the left of the image, as is the pinch point of the Dover Strait between Britain and France, top right. Here the Channel narrows to 33 kilometres, and the container traffic conflicts with one of the world’s busiest international ferry routes: Dover to Calais. The Channel has long been the UK’s bulwark, reinforcing a self-image of otherness, independence and indomitability most recently reflected in the country’s 2016 vote to leave the European Union. How leaving will change the established patterns of international trade visible in this picture is anyone’s guess. But what is clear is that in today’s world no country is truly an island. ❚ Richard Webb 31 August 2019 | New Scientist | 29 Views Culture The selling of happiness Fuelled by government and corporate dollars, being happy has become near mandatory. Douglas Heaven lifts the lid on an industry worth billions Book Manufacturing Happy Citizens: How the science and industry of happiness control our lives THEY say money can’t buy happiness. But that doesn’t stop people from selling it. Day passes to Goop’s wellness summit in London in June cost £1000, with weekend tickets (two nights in a hotel, a VIP Sunday workout and Goop-favourite meals) going for an eye-watering £4500. From mindfulness to detox to the nine crystals you should keep on your desk, actor Gwyneth Paltrow’s multi-million dollar business has it covered. There are so many ways you can pay to feel better about yourself. I closed Goop’s website soon after learning about shock-wave therapy for my penis. Happiness has become a commodity that needs to be topped up as often as possible. What do we want? To be happy. When do we want it? Now. At some point, our happiness became other people’s business. “Most of what we do on behalf of our happiness… is first and foremost favourable and beneficial to those who claim to hold its truths,” write Edgar Cabanas and Eva Illouz in the excellent Manufacturing Happy Citizens. Educational psychologist Cabanas and sociologist Illouz explain how happiness became not only a commodity, but also one that society has decided it is our civic duty to pursue. Happy people are better citizens. The book is a clear-sighted critique of capitalism’s current obsession 30 | New Scientist | 31 August 2019 IRA BERGER/ALAMY Edgar Cabanas and Eva Illouz Polity with happiness and of the shaky science allowing a well-meaning ideal to be so easily subverted by governments and companies. It is surprising that happiness (at least, as we know it today) has an origin story. In this tale, the prime mover is Martin Seligman, a behaviourist and cognitive “In his paper, Seligman wrote that positive psychology called to him just as the burning bush called Moses” scientist. In 1998, he was elected president of the American Psychological Association, the largest professional body for psychologists in the US. He had come to believe that psychology was too negative, focusing on pathologies, not betterment. Seligman wanted to make happiness the focus: what was it and how could we achieve it? It was a real calling. In his joint 2000 paper “Positive Psychology: An introduction”, published in American Psychologist, Seligman wrote that “Positive psychology called to me just as the burning bush called Moses.” But according to Cabanas and Illouz, “as is often the case with revelations, the picture of positive psychology presented in the inaugural manifesto was vague”. They say that Seligman cherry-picked ideas from a grab bag of disciplines he felt said something about the human condition, including evolutionary biology, psychology, neuroscience and philosophy. Seligman was clear about one thing, however: happiness studies shouldn’t be part of psychology but a new field. The authors argue that it wasn’t entirely new: positive psychology sounded a lot like the self-esteem movements of the 1980s and 90s, the humanist psychology of the 1950s and 60s, and the thinkyourself-well and mind cures promoted by the likes of Christian The impact of happiness research has been huge – just not on science Science at least 150 years earlier. The enterprise might have fallen flat if the money hadn’t poured in. Cabanas and Illouz quote Seligman saying that “grey-hair, grey-suited lawyers” from “anonymous foundations” that only picked “winners” would call him for meetings in fancy buildings in New York to ask what positive psychology was and request “ten-minute explanations” and “three-pager” proposals. Within two years of his paper, the field had attracted some $37 million. The John Templeton Foundation gave Seligman $2.2 million to set up the Positive Psychology Center at the University of Pennsylvania. The 2002 preface to the Handbook of Positive Psychology, which declared the field’s independence, was written by Templeton himself, Don’t miss Driving forces Nothing can be taken for granted in an autonomous future, finds Simon Ings Driverless: Who is in control? Science Museum, London Until October 2020 DURHAM Cathedral’s stained glass windows inspired artist Dominic Wilcox’s contribution to Driverless, a tiny but thought-provoking exhibition at London’s Science Museum. It occurred to Wilcox that artificial intelligence could make traffic collisions a thing of the past, which means “we don’t need the protection systems that are built into contemporary cars”, he told design magazine Dezeen. “We can just have a shell of any design.” His Stained Glass Driverless Sleeper Car of the Future (pictured below) is the sort of vehicle we may be driving when road safety has improved to the point where we can build cars out of whatever we want. It suggests a future in which safety is no longer a set of barriers, cages, buffers and lights, and is instead a dance of algorithms. Rather than measuring out a bike lane, say, we will have an algorithm that decides whether to leave a smaller distance to the bicycle on its left to reduce the chance of hitting a truck on its right. What if that causes more cyclists, but fewer passengers, to die every year? Such questions aren’t new. But they are having to be asked again and in a different and disconcerting form as we move more safety systems off the roads and into vehicles. On show is the Massachusetts Institute of Technology’s “Moral Machine”, a website using more than 40 million participants’ decisions on what to do in certain situations to inform our autonomous machinery design. The findings can be unsettling: would-be designers are more likely to sacrifice your safety if you are fat, a criminal or a dog. This is a show as much about possible futures as it is about the present. Interviews, archival footage, models and some interactive displays create a series of provocations, more than a fully fledged exhibition. I especially liked the look of the MIT Senseable City Lab and the AMS Institute’s “Roboats”, currently on trial on Amsterdam’s canals. These autonomous floating platforms form spontaneous bridges and event platforms and can transport goods and people. The exhibition spends much of its time off-road, investigating drone swarms and privacy, flocking behaviour and mine clearance, ocean mapping and planetary surveillance. Don’t let its size put you off: this little show is full of big surprises. ❚ An autonomous racing drone and a car made of glass: which future would you pick? Watch Open City Documentary Festival, in London from 4 to 10 September, presents Expanded Realities, an exhibition and symposium about how digital technology is changing and enriching non-fiction film. Visit Ars Electronica, since 1979 the big beast of the European science-art scene, is contemplating the digital revolution in middle age. Artists, scientists and tech pioneers of the past four decades will be gathered in Linz, Austria, from 5 to 9 September. Read The Nature of Life and Death (Putnam) by forensic ecologist Patricia Wiltshire blends science and true-crime reporting. It reveals the microscopic traces we leave behind us, and how these are used to reconstruct our most desperate acts. 31 August 2019 | New Scientist | 31 TOP: FOREST, KELSEY BONCATO, DANIEL OLDHAM. 2019, MIDDLE: OMAI USA Douglas Heaven is a consultant for New Scientist Exhibition © THE BOARD OF TRUSTEES OF THE SCIENCE MUSEUM apparently “thrilled by the project, given his interest in how individuals can control their minds to master their circumstances and shape the world”, write Cabanas and Illouz. The message spread via meetings, symposiums, textbooks and journals, aided by a receptive press. In its grand promises, there was something for everyone. Still more bodies paid for scholarships and prizes. The US National Institute on Aging and what is now called the National Center for Complementary and Integrative Health both funded research. Companies such as Coca-Cola invested, hoping to find ways to reduce employee stress and promote productivity. One of the largest grants now comes from the US Army through its $145 million Comprehensive Soldier Fitness project, run closely with Seligman and his centre. Is there anything in all this? Here, Cabanas and Illouz are careful. It is hard to take down a hugely successful area that has globally reinvigorated psychology departments. Still, there are many critics who attack everything from its theoretical simplifications to its methodological shortcomings. The authors write: “The field is characterized by its popularity as much as its intellectual deficits and scientific underachievement.” Though its scientific impact is questionable, elsewhere the impact of positive psychology has been huge. It has reshaped attitudes towards happiness, changing how firms think about staff, governments view citizens and how we think about ourselves. It feeds a billion-dollar wellness industry. At least some people have something to smile about. ❚ Views Culture The science fiction column A surfeit of snake oil Ordinary lives hang in the balance when self-appointed industry disrupters roll into town. Let’s hear it for novelists who puncture and poke fun at a business culture disconnected from its people, says Helen Marshall Helen Marshall is an editor, award-winning writer and senior lecturer at the University of Queensland, Australia. Follow her on Twitter @manuscriptgal Books The Return of the Incredible Exploding Man Dave Hutchinson REBCA The Warehouse Rob Hart Bantam Press Helen also recommends... Books The Silver Wind Nina Allan Titan Books A haunting collection of uncanny time-travel stories. World Engines: Destroyer Stephen Baxter Gollancz Follow a strange object on its 500-year orbit of Earth. 32 | New Scientist | 31 August 2019 DAVID ALAN HARVEY/MAGNUM Life in a one-horse town teaches you there is no such thing as a free lunch THE pulp novels of the 1950s are best remembered for their sense of wonder. This is exactly the feeling that billionaire tech funder Stanislaw Clayton tries to create in The Return of the Incredible Exploding Man, the latest novel by Dave Hutchinson, author of the deservedly praised Fractured Europe series. The 1950s were also a golden age for social satire: for Pohl and Kornbluth’s The Space Merchants, and Vonnegut’s Player Piano. Hutchinson’s new book is, in truth, more this sort of science fiction. It bites. The novel follows down-andout journalist Alex Dolan as he agrees to write a book documenting the history of Clayton’s latest project: the Sioux Crossing Supercollider. What Clayton has in mind is a PR exercise designed to build support for his struggling project. He gets a lot more than he bargained for. The bulk of the novel is a slow-burn account of Dolan’s investigation into the mysteries surrounding the project, part le Carré spycraft, part Crichtonesque scientific thriller. There is something of Stephen King, too, in the book’s close focus on the inhabitants of Sioux Crossing, ordinary folk transformed by Clayton’s regeneration of their town. For better or worse, they need him to succeed. If the project fails, it will take the town with it. In the finale, we might expect this book to live up to its pulpy “The Cloud has become the only game in town: a vast system of warehouses sustaining a mini-ecosystem” title, but by now Hutchinson has become more interested in the politics than in the science. Some readers might feel deflated, but Hutchinson’s point is well made: that we ought to be suspicious of technocrats bearing gifts. The Warehouse by Rob Hart is similarly interested in the effects of a billionaire’s ambitions on everyday people. In it, Gibson Wells, an American entrepreneur peddling a dangerous brand of ultracapitalism with folksy charm, creates The Cloud. In the wake of climate change and a ravaged economy, The Cloud has become the only game in town: a vast system of warehouses supporting a mini-ecosystem with its own living spaces, restaurants, social ratings and credit system. Think Amazon, but on steroids. Paxton, a former entrepreneur whose company failed after The Cloud undercut his business, has found work as a security officer, charged with stopping the flow of illegal drugs into The Cloud’s compound. Zinnia is ostensibly a picker, one of the redshirts running a daily marathon to locate cheap goods for drone delivery to the outside world. But she isn’t all she seems. A competing company has offered her a life-changing sum of money if she can ferret out The Cloud’s secrets. The Warehouse depicts a world of systemic abuse, petty corruption and a callous disregard for the things we need to be properly human. But while Hart spends a decent amount of time exploring Wells’s justification for The Cloud, Paxton’s complicity is the main point: will he buy into a system he knows is fundamentally broken or will he risk his relative comfort to tear it down? Ultimately, is The Warehouse a novel that puts the capstone on post-industrial capitalism? Not really. Rather than trusting his own story, Hart relies on references to Orwell, Atwood, Bradbury and Le Guin to explain his ethical stance. The result is an entertaining, almost cinematic read, but one that is content to let others do the intellectual heavy lifting. ❚ WHAT IF TIME STARTED FLOWING BACKWARDS? WHAT IF THE RUSSIANS GOT TO THE MOON FIRST? WHAT IF DINOSAURS STILL RULED THE EARTH? AVAILABLE NOW newscientist.com/books Features Cover story y Back stor Chronic back pain is on the rise, and the most common treatments may be making matters worse, finds Helen Thomson 34 | New Scientist | 31 August 2019 A RGHH.” The first time it happens it takes you by surprise. Was that me? Then it happens again, and again. You give a tiny groan every time you get off the sofa. You hold the bottom of your spine and stretch, wondering if you should see a doctor. Surely you are too young to have a bad back? That tends to be the start for a lot of us. Backache is an extraordinarily common burden, with one in four adults experiencing it right now, and 90 per cent of people having back pain at least once in their life. Last year, a series of papers in The Lancet revealed the extent of the problem: back pain is a leading cause of disability around the world. In the US alone it costs an eye-watering $635 billion a year in medical bills and loss of productivity. Much of the blame has fallen on our increasingly desk-bound lifestyles and growing lifespans, which mean more years of wear and tear on our spines. But these factors only partly explain how we got here and what makes some people more vulnerable or resilient. The World Health Organization expects back pain problems to steadily rise in the years ahead and to affect more people around the globe. That makes it especially worrying that the people who are trying to help are making the problem worse. The good news is we already have the knowledge to improve things – if we finally apply it. At the same time, new understanding of how and why our brains create the experience of pain is changing the way we think about those crippling aches and pointing to some surprising solutions. To understand the solutions, we must first travel back 7 million years, to when our ancestors caused the problem. In exchange for walking upright, we got back pain. At least, that is the hypothesis posited by Kimberly Plomp at the University of Liverpool, UK, and her colleagues. To find out why humans experience more spinal disease than non-human primates, Plomp’s team studied the shape of human, chimpanzee and orangutan vertebrae, the bones that make up your spine. They were looking for small bulges called Schmorl’s nodes that can occur in the soft tissues ANDREA UCINI “ between vertebrae and are linked to back pain. People who had these nodes had vertebrae that were more similar in shape to those of chimpanzees. “We started to walk on two feet relatively quickly in evolutionary terms,” says Plomp. “Perhaps some individuals with vertebrae that are more on the ancestral end of normal human variation are less well adapted to withstanding the pressures placed on the bipedal spine.” This ancestral vertebral shape then plagued us throughout our history because it didn’t affect our ability to reproduce, so evolution didn’t select against it. “People say they can tell you what is wrong from a scan. They can’t. It’s not possible” Yet despite its long evolutionary history, it is only in the past few decades that we have started to see an epidemic of chronic back pain (see graph, page 36). What changed? There is evidence that the rise of office culture plays a part. Several studies have found a link between spending more time sitting on the job and increased reports of lower back pain. Slumping in front of computer screens puts pressure on the muscles, ligaments and discs that support the spine and can deactivate muscles that promote good posture. Of course, backache can also be caused by accidents, sports injuries or a congenital disorder, but it is lifestyle factors such as obesity and smoking that are the real problem, says Rachelle Buchbinder at Monash University in Victoria, Australia, one author of The Lancet series. Smoking probably puts people at higher risk of lower back pain because it is associated with a clogging of the arteries, which can damage the blood vessels that supply the spine, leading to muscle and bone degeneration. Being overweight amplifies the mechanical strain on the back and decreases mobility, predisposing people to deterioration of discs in the spine. Obesity can also increase the production of inflammatory chemicals associated with pain. Unfortunately, identifying which of these problems has led to your own back pain is incredibly difficult. According to one study in the US, nearly a quarter of all primary care appointments for adults are for back pain. Less than 1 per cent of people who seek help will have something seriously wrong, such as an infection, inflammatory arthritis, cancer or a fracture, says Buchbinder. These people will usually have other red flags, such as fever, rapid weight loss or problems going to the toilet. Everyone else falls under the category of “non-specific back pain”, which usually improves in a matter of days or weeks. Yet many people and their doctors pursue MRI scans in the belief that they will provide an accurate diagnosis, and therefore quicker recovery. The trouble is, “by the time we’re 50, many of us will have abnormalities in our spine: degeneration of the discs, bulging, a little arthritis in the joints”, says Buchbinder. “Some of these may cause pain in some people but not others. There are lots of people that say that they can tell you what is wrong from a scan, but they can’t. It’s just not possible.” Getting a scan may not only be a waste of time and money, says Buchbinder, but it can actually worsen your back pain. Once you start to look for abnormalities, you will find them. Once that happens, doctors are more likely to prescribe painkillers, steroid injections or surgery, which may be unnecessary, ineffective and sometimes harmful. In 2003, Jeffrey Jarvik at the University of Washington in Seattle and his colleagues randomly assigned 380 people with lower > 31 August 2019 | New Scientist | 35 back pain to have an X-ray, which can identify things like fractures, or an MRI scan, which is used to look at soft tissues. A year later, there was no difference in their health outcomes, but those who had an MRI were more likely to have had surgery, exposing them to the risk of infection and other complications. “The potential for harm has been shown in many studies,” says Buchbinder. In countries like the UK, where doctors are advised against offering surgery for back pain, people are often offered anti-inflammatory steroid injections, but these have been shown to be no more effective than placebo. They can also cause increased appetite, mood changes and difficulty sleeping. Moreover, many doctors, particularly in the US, prescribe stronger painkillers than are necessary, says Buchbinder, fuelling the opioid crisis that has decreased life expectancy in the US. Backache is the number one reason for prescribing opioids, says Tamar Pincus, a health psychologist at Royal Holloway, University of London, despite several studies showing that safer treatments, such as non-steroidal anti-inflammatories, may offer similar relief. Not all back pain is bad. The initial pain we get from an injury alerts us to a problem and protects us from further damage. This mechanism can be critical to our survival. But chronic pain that lasts weeks, months or years after an injury has healed serves no useful purpose and can seriously harm our health. Most people assume that pain must always have a physical cause – an injured muscle or “Low mood and pain-related guilt increase the risk of pain becoming chronic” squashed disc, perhaps. Yet often there is no identifiable mechanical explanation. That is why many specialists instead focus on how and why we perceive pain. Fundamental to this idea is our understanding that pain is generated by the brain. Although we have cells in our body that send messages to the brain to alert us to potentially damaging stimuli, like heat, or a sharp object pressing against the skin, it isn’t necessary to stimulate these cells to feel pain, nor is their activity always directly related to our experience of discomfort. Irene Tracey, a clinical neuroscientist at the University of Oxford, was fundamental in uncovering these nuances. In the 1990s, her Growing pains 6 1990 2015 5 4 3 2 SOURCE: IHME Disability-adjusted life years (millions)* Disability related to lower back pain has increased dramatically around the world in the past few decades 1 Age group *A disability-adjusted life year is the equivalent of one lost year of “healthy life”, according to the WHO 36 | New Scientist | 31 August 2019 80 + 75 -7 9 70 -7 4 65 -6 9 60 -6 4 55 -5 9 50 -5 4 45 -4 9 40 -4 4 35 -3 9 30 -3 4 25 -2 9 20 -2 4 15 -1 9 10 -1 4 59 0 team showed that anticipation of pain made networks in the brain light up with activity, and that different aspects of our experience – the intensity of pain or anxiety caused by it – are controlled by separate brain circuits. All of these circuits can be triggered or suppressed. For instance, people who are depressed show greater activity in pain areas, but this can be subdued by listening to music or watching a gripping film. One experiment even showed that religious faith could have analgesic properties in the brain. When devout Catholics were shown pictures of the Virgin Mary while given a sharp pain, they rated their pain lower than atheists shown the same image. When both groups were shown a nonreligious painting, their pain rating didn’t differ. Scans showed that the religious iconography triggered a brain area in the Catholic group called the right ventrolateral prefrontal cortex, which inhibits pain circuits. With chronic back pain, understanding how the experience of pain can be manipulated by the mind is important to figuring out why it sticks around after an injury has healed – and what we can do to prevent this. Pincus points out, for instance, that low mood and painrelated guilt increase the risk of pain becoming chronic. “People start to feel guilty for dropping out of activities,” she says. “They then worry that people are going to judge them for that, so they don’t accept the activities in the first place.” After several bouts of back pain, people also start to process the world differently, says Pincus. Their pain becomes embedded within their “self-schema”: the things they associate with themselves. If they are shown an image of a staircase, for instance, their first thought is, “I can’t climb it”. “After a while, you see and feel things coated with pain,” says Pincus. “You no longer need the injury to feel pain. And you might experience more intense pain, purely because you’re expecting it.” So between our brain and the rest of our body, what can we do to avoid or diminish chronic back pain? First, you may want to rethink your back belt, shoe insoles and any other ergonomic products, since there is almost no evidence that they are effective. Once they are out of the way, it is time to get up and go. Despite doctors all over the world still prescribing bed rest, it is one of the worst things you can do. When young healthy male volunteers spent eight weeks in bed, their lumbar multifidus muscles, which keep our lower vertebrae in place, had wasted and become inactive. Some of SHAWN PATRICK OUELLETTE/PORTLAND PRESS HERALD VIA GETTY People who switch to standing desks say they feel less back pain the volunteers’ muscles had still not recovered six months later. “Many low-back-pain patients have a strong fear of moving,” says Luana Colloca, a pain specialist at the University of Maryland School of Nursing. Yet exercise can make all the difference. A study published in June found that exercises designed to strengthen the lower back help ease pain, and just walking regularly helps too. “We need to remove this fear and persuade ourselves to exercise,” says Colloca. Small changes in how we work can also help. People with chronic back pain who used a standing work station for three months saw a significant decrease in the worst pain they felt, and their general pain at the end of the study. If chronic back pain is already plaguing you, give some thought to your mind. “It’s no good asking someone to stop thinking about their pain,” says Pincus. “It’s like telling someone not to think of a white elephant.” Instead we should concentrate on reframing the world so that the things you like doing don’t lead your thoughts back to pain. For instance, Pincus herself experiences chronic pain after a knee injury, but says that when it hurts when she is out with her children, she feels happy, rather than sad. “I feel fantastic. I think: ‘You’re an amazing mum because you’re out walking with your kids.’ How we think about our pain may not affect the pain intensity, but it does affect the ability of that pain to infiltrate our daily lives, which creates that negative cycle that can destroy our lives.” Back me up Clinicians also need to do their bit, says Pincus. When we are injured, our friends say: “Ooh, that must hurt.” They acknowledge our pain. Doctors often forget to do so, and that matters. In one study, 50 people were asked to hold a bucket of sand with a straight arm for as long as they could, while listening to a distressing sound. It is a surprisingly painful task. Immediately after, they were asked to perform tests in which they had to recall lists of words. They then chatted to an examiner who either validated or invalidated their pain, before recalling as many words from the original tests as possible. Most participants told the examiner that they found the task difficult, that it hurt their arm and that they were disappointed that they couldn’t hold the bucket for longer. In the validation group, the experimenter replied: “That’s a really common response, many people feel surprised over the level of pain that the task brings about. When something looks easier than it is, it’s often hard to live up to one’s own expectation.” In the other group, the experimenter would say: “That’s strange. Nobody else described their experience this way. No wonder you’re disappointed.” People whose painful experience was dismissed remembered fewer words on average and three times as many words that weren’t there, compared with the group whose pain had been acknowledged. “Until you get validation of your pain, your brain’s resources are completely swept up with how to communicate your suffering,” says Pincus. “Doctors need to acknowledge this. If patients are able to be heard, they can understand.” The best way to prevent long-term disability from back pain is to ditch the drugs and promote wider international adoption of a mix of increasing physical activity plus mental retraining, suggest Buchbinder and her colleagues. There is reason to hope that plan will work. In the Australian state of Victoria, workers’ compensation claims for back pain tripled in the early 1990s. Then in 1997, a statewide public health campaign encouraged people to avoid bed rest and unnecessary scans. It also gave them tips on how to think about pain and its impact on their life. By the time the campaign was over, there was a significant drop in the number of claims for compensation for back pain, compared with a nearby state, which saw no change. When you are in pain, the last thing you expect to be told is that you should stay away from the doctor and get back to work. For backache, that may truly be the best advice, says Buchbinder. Perhaps we need to start thinking about bouts of back pain the way we think about other common ailments, says Pincus. “Nobody expects to get through life without a cold,” she says, “and they don’t visit the doctor when they do.” ❚ Helen Thomson is the author of Unthinkable: An extraordinary journey through the world’s strangest brains 31 August 2019 | New Scientist | 37 Features Arctic rescue squad If we want to save the Arctic, we might have to intervene directly. Rowan Hooper investigates three ambitious projects to bring back the ice 38 | New Scientist | 31 August 2019 T HE Arctic is in a death spiral. The top of our world is heating up faster than anywhere else on the planet, setting new records for the speed and area of ice melt. We are on track this year to have one of the lowest summer sea ice coverages so far. It is a huge problem, because what happens in the Arctic doesn’t stay in the Arctic. What’s more, the Greenland ice sheet, which alone contains enough water to raise global sea levels by 6 metres, is disappearing. The frozen Arctic soil and sediment, or permafrost, is melting, releasing more and more carbon dioxide and methane into the atmosphere. This year, vast wildfires in the peatlands of Siberia have blazed for more than a month, and the Arctic warming is playing havoc with weather systems in the northern hemisphere too. But if you prefer to think simply in terms of money, the economic impact of unmitigated Arctic warming by the end of this century was recently estimated to be $67 trillion. As US congressman Jerry McNerney says: “When it comes to the Arctic, we’re in deep shit.” You’ve heard the slogans: we are living in a time of climate emergency. But it is no good declaring an emergency without summoning help. So here it is: let’s refreeze the Arctic. There are several imaginative ideas to manipulate its climate system to get the ice back. They won’t be cheap or easy, but some researchers argue that the crisis in the north is too serious not to at least investigate ways to engineer the return of the ice. Climate intervention in the Arctic might be more necessary than it first appears because the region’s death spiral is a feedback loop. As the shiny ice melts, models and satellite images suggest we could get a sea ice-free summer any year now. When the ocean is exposed, instead of reflecting sunlight, the dark water absorbs more of the sun’s heat. Over the past 30 years, this change corresponds to a warming equivalent to a quarter of all the carbon dioxide released by human activity during that time. The warming is weakening the polar jet stream – the fast-flowing, highaltitude air current – in the northern CHRISTOPHER MICHEL In 40 years, about 2.4 million square kilometres of Arctic sea ice has disappeared hemisphere, resulting in more“blocked” weather patterns, and corresponding droughts, floods and heatwaves. The global risks are huge. “Allowing the Arctic to change in unrecoverable ways poses an enormous safety risk to communities around the world and could move the climate system beyond our ability to recover,” says Kelly Wanser, director of SilverLining, a geoengineering NGO based in Washington DC. Of course, we could have prevented the Arctic from warming as much as it has if we had cut global greenhouse gas emissions when scientists first started advising us to do so, decades ago. But we didn’t, and nor are we now. “It’s a pious hope and anyway it would take a while,” says Peter Wadhams, head of the Polar Ocean Physics Group at the University of Cambridge. This is why a growing number of scientists argue that, if we want to save the Arctic, we need to intervene directly by manipulating its climate system. There are three main proposals for doing this: increasing the extent of sea ice; “It is no good declaring a climate emergency without summoning help. So here it is: let’s refreeze the Arctic” artificially brightening the surface of the ice to reflect more sunlight; and cooling the Arctic air by brightening the clouds to deflect sunlight. All three ideas are forms of geoengineering: intervention in the environment on a scale big enough to counteract climate change. The concept bothers many scientists because they fear that the idea of a technological fix will undermine efforts to cut carbon dioxide emissions. “Well, we’re not making them anyway,” says Cecilia Bitz, a sea ice physicist at the University of Washington in Seattle. “Maybe intervention would be positive, showing that we have the capacity to improve the environment.” For those advocating such action, a big concern is the methane already streaming out of the seabed as microbes break down thawed organic matter. “The fear is that this will grow from being a set of methane plumes to an outbreak,” says Wadhams. “So we need to bring back the ice around the coastal seas, and that might save us from a catastrophic methane burst.” As well as this methane trapped under the sea, an estimated 1 trillion tonnes of carbon are in the top 3 metres of Arctic soils. If only a small fraction of this reaches the atmosphere, it will overwhelm any cuts in emissions we have made. “It seems that nature offers us a choice: instant methane from the seabed giving us a huge immediate burst of warming, or longer, slower warming from complex chemical processes as terrestrial permafrost thaws. Except that it’s not an ‘or’, it’s an ‘and’.” The first potential solution comes from Steve Desch, an astrophysicist at Arizona State University. His plan is to build windmills that pump seawater onto surface ice during the winter, where it will freeze, thickening the sea ice and extending its coverage. This method was recently proposed to prevent the collapse of the Antarctic ice sheet too. Sea ice moves around, so Desch’s idea is to locate the windmill-pumps on sea ice in the north of the Arctic. This would help thicken chunks of ice that are then protected from melting when they move south. “While that may seem like an impossible task, since the Arctic is a very large place, we outlined a mechanism, using simple, brute-force, steampunk technology that is not impossible, but enormous in scope,” he says. “It’s not like a space mirror larger than the Earth or something. It’s pretty simple, but just a big job.” Desch has calculated that we would need > 31 August 2019 | New Scientist | 39 How to be Superhuman Rowan Hooper is speaking at New Scientist Live about people at the peaks of human potential newscientistlive.com Last ice? About one-third of the Arctic’s summer sea ice has disappeared over the past 40 years. This is an area of approximately 2.4 million square kilometres – roughly the size of Algeria Sept 1979 7.1 million km2 Sept 2018 4.7 million km2 Algeria 2,382,000 km2 “Arctic sea ice may be restored by brightening ocean stratocumulus clouds” ALEXANDER SHOLTZ ALEXANDER SHOLTZ Reflective microspheres (below left) are being used to preserve winter ice in North American lakes (right) 40 | New Scientist | 31 August 2019 10 million windmills across the entire Arctic to refreeze it, at a cost of $500 billion. That is a huge sum, but just a fraction of the estimated $67 trillion economic impact of Arctic warming if we don’t act. Bitz has evaluated Desch’s idea in a paper currently submitted for publication. “The physics can work,” she says. “The basic principles make sense. To me that’s promising.” But so far, Desch only has a prototype windmill that works in the lab. For a true test, field trials are essential. The second proposal for geoengineering the Arctic has had some success outside the lab. It involves covering the ice with shiny, white beads. The idea is that these microbeads increase the reflectiveness, or albedo, of thin, young ice, so protecting it from the sun. The leading advocate is Leslie Field, an engineer at Stanford University in California, who also runs Ice911 Research, a non-profit organisation exploring methods of restoring Arctic ice, mainly using hollow silica microspheres. These bright, non-toxic beads are chemically and physically similar to sand but smaller, more like powder, with a diameter of about 65 micrometres (0.065 millimetres). Field and her colleagues have tested the idea, most notably on about 4200 square metres of North Meadow Lake in Alaska. They have shown that the microspheres increase albedo by around 20 per cent and slow the ice melting. To cover 25,000 square kilometres of the Arctic with the stuff would cost about $300 million for the materials alone, says Field. This represents just 0.7 per cent of summer ice coverage at its lowest extent on record: 3.4 million square kilometres in 2012. Yet many questions remain, not least whether it works on sea ice – so far it has only been tested on frozen lakes. And what happens to the beads when ice melts? Some sink and are incorporated into the mud on the lake floor, says Field. There are, however, concerns about the biological hazards of this approach. Bitz says she is worried about the ecological impact of adding millions of tonnes of silica to the Arctic. “For me this raises a red flag,” she says. Ken Caldeira, who researches geoengineering at the Carnegie Institution for Science in California, has doubts about the workability of modifying the surface of the ice – whether by the methods proposed by Field or Desch – and about whether this could be an effective tool against climate change. “I am highly sceptical that this approach will prove feasible and desirable at scales required to be climatically substantial,” he says. For Bitz, Wadhams and several other climate scientists who spoke to New Scientist, the most promising potential intervention is one that doesn’t involve tinkering with the ice directly. Instead, it entails brightening the clouds over the Arctic. The idea dates back to the 1990s, when John Latham, now at the University of Manchester, UK, started thinking about ways of limiting the greenhouse effect by reducing the amount of sunshine reaching the planet’s surface. Latham was fascinated by something called the Twomey effect, which describes how the amount of solar radiation that clouds reflect back into space depends on the concentration of tiny particles around which cloud droplets form. He realised that you could increase this concentration over oceans by seeding clouds with tiny droplets of salt water. We know from satellite images of ship tracks – the equivalent of the contrails left by airplanes – that clouds can be seeded by the sulphate emissions from ships. Latham and his colleagues have produced computer models showing how Arctic sea ice may be restored by brightening ocean stratocumulus clouds. These large, rounded clouds are by far the most common kind seen in the Arctic, and are usually found in groups covering huge areas. On paper, it looks promising, but testing it for real is quite another matter. To do so will require a system that can spray an ultra-fine mist of sea water into the lower atmosphere over a large area of ocean. Stephen Salter, an engineer at the University of Edinburgh, UK, has well-advanced plans for this, having Cloudbusting Clouds play a vital part in controlling our climate. Their reflection of the sun’s rays, especially at the tropics, is essential for cooling Earth. But we don’t know how cloud formation will change as the planet gets hotter. This means we don’t know how much warmer Earth will become for a given increase in carbon dioxide concentration in the air. Climate change deniers often point out that there is too much variability in the predictions climate models make about warming. One reason is a lack of certainty about so-called climate sensitivity. This is a measure of the amount of warming that results from a doubling of carbon dioxide in the atmosphere. In climate models, it ranges from 2°C to 5°C. We don’t know if our climate is particularly sensitive – in that a doubling of CO₂ gives a correspondingly large increase in heating – or if it is resilient. But Tapio Schneider, a climate scientist at California Institute of Technology in Pasadena, says evidence from improved recent climate models points towards the planet being more sensitive than we thought, which means we should be very worried. If it is that sensitive, then we will get 1°C of additional warming from adding a mere 70 parts per million or so of CO₂ to the atmosphere – which would take about 20 years at the current rate. That would take us over 2°C of global warming since pre-industrial times, the level at which “severe impacts” are expected: more wildfires, longer periods of drought in some regions and an increase in the number and intensity of tropical storms. Cloud formation is boosted by atmospheric particles called aerosols, many of which are pollutants from dirty industrial processes and fossil fuels. As these particles have a cooling effect on the planet, both directly and through their action on cloud formation, phasing out their sources will unmask previously concealed greenhouse gas warming. So to understand the extra bump of warming we can expect when the atmosphere gets cleaner, we need to figure out how clouds contribute to climate sensitivity. “Marine cloud-brightening experiments have the potential to shed light on one of the most vexing and important questions in climate science, namely how aerosols affect clouds,” says Schneider. “It behooves us to do everything we can to understand the climate system better, before we try to manipulate it.” NASA/ROBERT SIMMON &JESSE ALLEN/JEFF SCHMALTZ, MODIS RAPID RESPONSE TEAM Predicting warming means deciphering the role of clouds developed proposals for remotely operated drone ships able to deliver the spray, which he presented to the UK government’s Environmental Audit Committee’s 2017 inquiry into Arctic sustainability. The thing holding him back is lack of funding. For the price of Neymar Shortly after I started corresponding with Salter, he sent me a photo of Brazilian footballer Neymar, beaming as his transfer to Paris St Germain was announced in 2017 at a cost to the French club of £198 million. Salter’s point was made clear when he detailed the costs of his cloud-seeding project. For the price of Neymar, researchers could conduct all the preliminary trials and then run an entire fleet of ships for two years that might start to restore the damage done to the Arctic. “Among ideas to prevent Arctic collapse, the most viable in terms of the scale and nature of the problem involve increasing the reflection of sunlight from the atmosphere,” says Wanser, who is also an adviser to the University of Washington’s Marine Cloud Brightening Project. “However, our effective level of investment in sunlight reflection is zero. This leaves us with an enormous exposure to near-term climate risk and not enough fast-acting options to keep warming within safe levels.” Several scientific assessments have identified marine cloud brightening as one of the most promising methods to manage sunlight levels, says Rob Wood at the University of Washington. We don’t yet know how effective cloud brightening might be. But there is another reason to do this research: it could help solve one of the biggest puzzles related to how warm our planet could get (see “Cloudbusting”, left). In the meantime, the region continues to turn from white to blue. Wadhams, who has led 40 expeditions to the Arctic, has seen enormous change in that time. “When I started going to the Arctic, you could think of the whole of the northern hemisphere as a solid continent,” he says. “Ice connected Eurasia and North America. But now you have blue ocean. Physically and psychologically, the world is fragmented, and I think that is having an important change in how people think.” ❚ Rowan Hooper (@rowhoop) is head of features at New Scientist and author of Superhuman: Life at the extremes of mental and physical ability 31 August 2019 | New Scientist | 41 Features Big question Is there anybody out there? I T IS the biggest question in the universe: are we alone? Philosophers have debated the question for millennia. When 16th-century Italian astronomer and Dominican friar Giordano Bruno declared that the cosmos contained “an infinity of worlds of the same kind as our own”, he was directly contravening religious dogma. He was later burned at the stake during the Inquisition, in part for daring to question Earth’s unique status. The debate continues, in more restrained fashion, to this day. For some, the sheer size of the universe makes it unlikely that life formed only once. For others, the remarkable complexity of life on Earth is testament to its uniqueness. Until recently, vague philosophical answers of this kind were the best science could do. The signs of life were far too ambiguous to pin down for certain, and our nearest potentially habitable worlds were too small and distant to test. But for the first time in human history we are reaching the technological sophistication needed to provide a genuine answer. Powerful telescopes are letting us study planets in other solar systems, giving us a glimpse into their atmospheres and a flavour of what type of life might be living on their surfaces. At the same time, improved analysis of our own planet is allowing us to redefine what life might look like from afar, and is helping us to distinguish the signs of a flourishing alien civilisation from 42 | New Scientist | 31 August 2019 the mere geological rumblings of a lifeless world. With these tools at our disposal, answers are finally within our grasp. To understand my optimism, it is worth revisiting the work of astronomer Frank Drake. In 1961, Drake devised a formula to estimate how many advanced civilisations were capable of signalling their presence in the Milky Way. His eponymous equation depends on breaking down that big unknowable quantity into a number of more tractable ones that can be multiplied together, such as the number of stars in the galaxy and the fraction of those likely to have planets (see “Quiet neighbourhood”, page 45). Even with pessimistic values, the existence of millions of technological civilisations seems likely. The main bottleneck on that apparent explosion of life, however, is in Drake’s final term: the average lifetime of a communicating civilisation. Humans have been broadcasting radio signals that escape into space for only about a century, and, in the current geopolitical climate, who is to say how many more years we have left. If you take the pessimistic assumption that intelligent life destroys itself rather quickly, the Drake equation suggests that statistically we are alone in the galaxy. If intelligent civilisations survive for millions, or even billions of years, however, then the Milky Way should be teeming with aliens. This calls for optimism, but also caution. After all, if there are millions of alien BETH HOECKEL After millennia of guesswork, we can finally start finding out for certain, says astrobiologist Sarah Rugheimer civilisations out there, then why haven’t we seen signs of them already? This seeming contradiction is sometimes called the Fermi paradox, after Italian physicist Enrico Fermi, who gave it its most succinct expression. With a back-of-the-envelope calculation, he showed that a single space-faring civilisation could easily colonise a galaxy within a hundred million years. Because the universe is 13.8 billion years old, and no interstellar colonists have yet appeared on our horizon, Fermi asked: where is everybody? Radio silence There are many proposed answers to this question (see “Solutions to the Fermi paradox”, page 44). Perhaps, say some, the aliens are already here, just keeping their identities secret. Perhaps they are deliberately steering clear of Earth, treating it as a sort of cosmic heritage site that deserves their protection. Or alternatively, there are simply no aliens out there. As an astrobiologist, I prefer to believe that aliens are out there; we simply haven’t communicated with them yet. It isn’t hard to imagine why this could be the case. Alien civilisations might well be millions of years ahead of us in their technological advancement. Trying to communicate with them using our primitive technology would be as absurd as teaching a ladybird to use a telephone. That hasn’t stopped us trying, of course, whether by including artefacts, such as plaques etched with celestial maps and images of humans, on our long-distance spacecraft or by broadcasting targeted radio messages into the depths of space. So far, no reply. All hope is not lost. The Fermi paradox and Drake equation specifically deal with the question of intelligent life, with the ability to communicate, travel and colonise. But only a fraction of the life we know of would be capable of these feats. Today, the vast majority of Earth’s biosphere consists of microbes. Single-celled organisms dominated the planet’s surface for nearly 3 billion years before multicellular life began. What is more, microbial cells not only outnumber human cells on our planet, they even outnumber them on and in your body. If life exists elsewhere in the universe, chances are it is microbial. This means that the first detection of alien life is unlikely to come from eavesdropping on an interplanetary conversation. Instead, we will need to scan the atmosphere of other planets for familiar molecules that primitive microbes are likely to emit: as close as we can get to a fingerprint of life. > 31 August 2019 | New Scientist | 43 What does life look like on other planets? Hear Geraint Lewis speaking at New Scientist Live newscientistlive.com Solutions to the Fermi paradox In 1950, physicist Enrico Fermi was having lunch with his colleagues when he asked a profound question: where is everybody? He wasn’t referring to the emptiness of the university cafeteria, but why, if we calculated that the universe should be filled with extraterrestrial life, none had as yet crossed our radar. Over the decades since then, various creative solutions to Fermi’s paradox have been proposed. THEY ARE ALREADY HERE This solution remains surprisingly popular, positing an international conspiracy to cover up the evidence of alien contact. THEY DON’T WANT TO DISTURB Perhaps aliens have some “prime directive”, as fictional space explorers in the TV and film series Star Trek do, to not interfere with the development of less advanced cultures on other worlds. Or maybe extraterrestrials regard us as a sort of national park or zoological garden, watching our movements but hiding their presence. THEY WON’T LIVE LONG ENOUGH TO GET IN TOUCH The depressing possibility exists that no advanced civilisation survives long enough to still be around when its neighbours are thriving. This idea is called the Great Filter. We may have already unknowingly passed through the filter unscathed, or it may be looming, in which case threats such as nuclear war and climate change might spell our doom. WE ARE ALONE IN THE UNIVERSE Might the simplest answer be the best, after all? 44 | New Scientist | 31 August 2019 An obvious place to start is with our own planet. If alien astronomers were observing Earth from a remote star system, would anything about it grab their attention? Compared with our rocky neighbours Mars, Venus and Mercury, the distinctive mix of oxygen and methane in Earth’s atmosphere would be sure to trigger interest. Oxygen makes up 21 per cent of the atmosphere now and is entirely due to life, entering the atmosphere from photosynthetic bacteria and plants that convert sunlight into energy. We aren’t sure when exactly oxygenic photosynthesis evolved, but there are clear signs that our atmosphere filled with oxygen 2.33 billion years ago. Methanogens, the microbes that produce methane, existed even earlier. Despite the biological origins of both gases, neither on its own is a sure sign of life. Methane, for example, is also produced by volcanoes and hydrothermal vents, although methane with an organic origin has a higher carbon-12 to carbon-13 isotope ratio. Oxygen could be formed when radiation from an active star splits molecules of water into hydrogen and oxygen, with the lighter hydrogen escaping from the planet’s atmosphere. In combination, however, methane and oxygen tell a story of a planet swarming with life. In the 1960s, astronomers realised that the existence of each gas was fatal to the other. Without large quantities of both oxygen and methane being continuously pumped into the atmosphere, these gases would quickly react and destroy each other. Individually you might expect a lifeless planet to contain either oxygen or methane. But geology alone doesn’t provide a way to maintain both. This means that finding oxygen and methane coexisting in appreciable quantities on a distant planet is a pretty good indicator of life. What’s more, life on Earth produces thousands of other molecular gases that seem to be unique. Methyl chloride, dimethyl sulphide and nitrous oxide have all been proposed as promising biosignature targets. What if our search for all of these gases comes up empty? Does that mean a planet is an arid ball of rock? Not necessarily. Life on a distant world may be totally different to that on Earth. It could be hiding under the surface, within solid rock or in hidden seas, where it would be effectively invisible. More radical alternatives are also possible. It could be based on silicon, for example, rather than carbon, or run on unknown metabolisms that use a liquid other than water. For these types of weird life, synthetic biology and research into alternative biochemistries could help us understand what unique chemicals to look for. Sara Seager at the Massachusetts Institute of Technology is trying to tackle this problem, working her way through all the molecules whose presence might indicate the existence of life. One of my favourite ideas comes from another MIT researcher, Clara Sousa-Silva, who says we should look for phosphine as a sign of life. Phosphine is a gaseous compound of phosphorus and hydrogen that is produced “Finding no life elsewhere may lead us to take better care of our own world” Quiet neighbourhood Nu w m ith pl be an r o pl an et f h et sp a s b Fr ac er s ita b th tion tar le at o de f t ve ho Fr lo se ac p w tion life plan ith o et s i n f th t e o Fr l s l ig e ac e p de tion nt lan li te o e ct f c fe ts ab iv le ilis , t at ec io hn ns Li fe ol th tim og a ica t re e of l s lea th ig se os na e ls civ ilis at io ns n n of st ar s at io rf or m Fr ac tio of st a Ra te Co m m un ica tiv e civ ilis at io DRAKE EQUATION ns Frank Drake’s 1961 equation remains the best method to get a rough sense of how many detectable alien civilisations should exist within our galaxy (N). According to the latest data, that number is somewhere between 1 – our lonely selves – and an impressive 4 billion N = R* x fp x ne x fl on Earth by anaerobic microbes, which don’t rely on oxygen to survive. Not only would it be relatively easy to detect in an exoplanet’s atmosphere, but it is the simplest gas that can’t be produced by any natural processes we know of. Detecting phosphine, in other words, could indicate an anaerobic biosphere. If coming up with such hypotheses seems challenging, putting them to the test is something else entirely. The first step is to identify candidate exoplanets: those with the right temperatures to nurture the complex chemistry needed to sustain life. At present, finding worlds beyond our solar system is usually done by looking for the slight dimming that happens when a planet crosses in front of its star. It is a process hundreds of times more difficult than spotting a firefly crossing a searchlight on the other side of the Atlantic. This detection method also opens the door to sensing different types of molecules in the atmosphere of a temperate and rocky planet. For example, when light from a star passes through the air cloaking such worlds it can reveal the composition of that air. Different x fi x fc x L molecules respond to different wavelengths of light, and by separating the light we collect in our telescope into different wavelengths, we could see the telltale spectra, or light signals, produced by substances such as oxygen, ozone, methane, water and carbon dioxide. What makes it such an exciting time to work in this field is the number of missions being developed to perform this task. The first of these will be NASA’s James Webb Space Telescope, scheduled to launch in 2021. This will be our first hope at identifying molecules in the atmosphere of a habitable exoplanet. ARIEL, a European Space Agency mission due to launch in 2028, will continue this effort. Another promising technique involves using large ground-based telescopes to do the same thing. These include the European Southern Observatory’s Extremely Large Telescope, currently being built in Chile and due to start working in 2025. Observing planet atmospheres from Earth’s surface is difficult because you must first remove our planet’s atmosphere from the signal. Next-generation ground observatories will be able to do just that by subtracting its effects from the light entering the telescope. This detailed technique can even allow us to distinguish isotopes on other worlds, subtly different versions of the same atoms that differ only by the presence of a single neutron in their nuclei. That is something I never dreamed would be possible in my lifetime. For all the excitement surrounding far-flung planets, perhaps the first successful detection of extraterrestrial life will happen closer to home. Certainly, other places in our solar system have conditions suitable for life as we know it, such as in the liquid water ocean hidden beneath a thick ice layer on Jupiter’s moon Europa or in the subsurface water on Mars. Alternatively, some have suggested that life could reside on Saturn’s moon Titan, swimming in its lakes of liquid methane. Whatever we find on these nearby worlds, I am confident life exists elsewhere in the universe. But confidence isn’t enough. Over the next few years, our searches are going to become more accurate, more thorough and capable of looking further than before. The answers we find stand to fundamentally shift our understanding of the universe and our place in it. As the science fiction writer Arthur C. Clarke put it: “Two possibilities exist: either we are alone in the universe or we are not. Both are equally terrifying.” To my mind, finding alien life would humble our apparently exalted status in the cosmos. We would be just one more example of life as a planetary process, crystallising out of the molecules that make up our universe. Searching widely and finding nothing would be equally sobering, however, indicating that even in environments we think of as habitable, the chasm between chemistry and simple life is vast. Hopefully, such an appreciation of life’s rarity would lead us to protect all forms of existence on our own world, reminding us that Earth is the only home we have. The next two decades will witness a revolution in exoplanetary science. We have already found dozens of potentially habitable worlds and the next technological advancement in observations will be able to detect potential biosignatures in their atmospheres. Now we need to watch – and wait. ❚ Sarah Rugheimer is an astrobiologist at the University of Oxford, UK 31 August 2019 | New Scientist | 45 Recruitment POSTDOCTORAL POSITION newscientistjobs.com Recruitment advertising Tel +1 617-283-3213 Email nssales@newscientist.com Vascular smooth muscle and endothelial cell ion channels Postdoctoral position immediately available to study physiological functions and pathological alterations in arterial smooth muscle and endothelial cell ion channels. Projects include studying blood pressure regulation by ion channels and regulation RIWUDI¿FNLQJVLJQDOLQJDQGIXQFWLRQVRI 753%.&D.YDQGYROWDJHGHSHQGHQW &DFKDQQHOVVLPLODUWRVWXGLHVZHKDYH UHFHQWO\SXEOLVKHG /HRHWDO31$6 .LGGHWDO6FLHQFH6LJQDOLQJ/HRHWDO 6FLHQFH6LJQDOLQJ%XOOH\HWDOH/LIH Bring your career to life Sign up, create your own job alerts and discover the latest opportunities in life sciences at newscientistjobs.com 7HFKQLTXHVLQWKHODERUDWRU\LQFOXGH 573&5:HVWHUQEORWWLQJELRWLQ\ODWLRQ LPPXQRÀXRUHVFHQFH)5(7SDWFKFODPS HOHFWURSK\VLRORJ\FDOFLXPLPDJLQJ SUHVVXUL]HGDUWHU\P\RJUDSK\EORRG SUHVVXUHWHOHPHWU\DQGFRQGLWLRQDONQRFNRXW PRXVHPRGHOV([SHULHQFHZLWKPROHFXODU ELRORJ\LRQFKDQQHOELRFKHPLVWU\SDWFK FODPSHOHFWURSK\VLRORJ\DQGFDUGLRYDVFXODU physiology preferred. 5HTXLUHGTXDOL¿FDWLRQVLQFOXGHD3K'RU 0'LQ3K\VLRORJ\RUDUHODWHG¿HOG6HQG curriculum vitae and names and addresses RIWKUHHUHIHUHQFHVWR'U-RQDWKDQ +-DJJDU0DXU\%URQVWHLQ(QGRZHG 3URIHVVRURI3K\VLRORJ\'HSDUWPHQW RI3K\VLRORJ\8QLYHUVLW\RI7HQQHVVHH +HDOWK6FLHQFH&HQWHU8QLRQ$YHQXH 0HPSKLV7186$ jjaggar@uthsc.edu. https://www.uthsc.edu/ physiology/faculty/jjaggar.php @science_jobs #sciencejobs 46 | New Scientist | 31 August 2019 87+6&LVDQ(TXDO(PSOR\PHQW$I¿UPDWLYH$FWLRQ7LWOH9,,; 6HFWLRQ$'$$'($(PSOR\HU newscientistjobs.com Assistant Professor of Chemistry The University of Chicago: Physical Sciences Division: Department of Chemistry Postdoctoral Fellowships in Cutaneous Biology NIH T32-funded postdoctoral fellowships are available in the Department of Dermatology DQGDI¿OLDWHGGHSDUWPHQWV7UDLQLQJRSSRUWXQLWLHVH[LVWLQFXWDQHRXVRQFRORJ\VNLQVWHP FHOOELRORJ\VNLQDJLQJELRLQIRUPDWLFVDQGWKHJHQHWLFVDQGLPPXQRORJ\RISVRULDVLVDQG RWKHULQÀDPPDWRU\VNLQGLVHDVHV6XFFHVVIXOFDQGLGDWHVZLOOSRVVHVV0'3K'RU0' 3K'GHJUHHVZLWKUHOHYDQWOLIHVFLHQFHVDQGRUVWDWLVWLFDOWUDLQLQJDQGZLOOEHLQWHUHVWHGLQ DFDUHHULQ'HUPDWRORJ\FXWDQHRXVELRORJ\UHVHDUFK &RUHIDFXOW\LQWKH'HSDUWPHQWRI'HUPDWRORJ\LQFOXGH'UV$'OXJRV] GOXJRV]D#PHG XPLFKHGX -7(OGHU MHOGHU#XPLFKHGX *-)LVKHU JM¿VKHU#PHGXPLFKHGX -( *XGMRQVVRQ MRKDQQJ#PHGXPLFKHGX /&7VRL DOH[WVRL#XPLFKHGX DQG6:RQJ VXQQ\Z#PHGXPLFKHGX $GGLWLRQDOPHQWRUVDUHDYDLODEOHLQRWKHUGHSDUWPHQWV Information about the Training Program is available at: KWWSVPHGLFLQHXPLFKHGXGHSWGHUPDWRORJ\UHVHDUFKUHVHDUFKWUDLQLQJ postdoctoral-training-grant Research descriptions for U-M faculty are available online at: KWWSVH[SHUWVXPLFKHGXGLVFRYHUH[SHUWVBSXEOLFDWLRQ 'XHWRUHVWULFWLRQVRIWKH7IXQGLQJPHFKDQLVPRQO\86FLWL]HQVRUSHUPDQHQW residents are eligible to apply Please send CV and references to:: -DPHV7(OGHU0'3K''HSDUWPHQWRI'HUPDWRORJ\8QLYHUVLW\RI0LFKLJDQ0HGLFDO 6FKRRO HPDLOMHOGHU#XPLFKHGX $SSOLFDWLRQVSUHIHUUHGE\6HSWHPEHU 7KH8QLYHUVLW\RI0LFKLJDQLVDQ(TXDO2SSRUWXQLW\$I¿UPDWLYH$FWLRQ(PSOR\HU Location Chicago, Illinois Description The Department of Chemistry at The University of Chicago invites applications for the position of Assistant Professor of Chemistry in all areas of chemistry. Applicants must apply online at apply.interfolio.com/66199 and upload a cover letter, a curriculum vitae with a list of publications, a succinct outline of research plans and a one page teaching statement. In your cover letter, please specify one sub-discipline that best represents your research interests (inorganic, materials, organic, physical, theoretical or chemical biology). In addition, three reference letters are required. 8\HSPÄJH[PVUZ At the time of hire the successful candidate must have completed all YLX\PYLTLU[ZMVYH7O+PU*OLTPZ[Y`VYHYLSH[LKÄLSK1VPU[HWWVPU[TLU[Z^P[O other departments are possible. Application Instructions Review of applications will begin on October 07, 2019 and will continue until all WVZP[PVUZHYLÄSSLK Apply to: apply.interfolio.com/66199 Equal Employment Opportunity Statement ;OL<UP]LYZP[`VM*OPJHNVPZHU(ɉYTH[P]L(J[PVU,X\HS6WWVY[\UP[`+PZHISLK =L[LYHUZ,TWSV`LYHUKKVLZUV[KPZJYPTPUH[LVU[OLIHZPZVMYHJLJVSVY religion, sex, sexual orientation, gender identity, national or ethnic origin, age, status as an individual with a disability, protected veteran status, genetic information, or other protected classes under the law. For additional information please see the University’s Notice of Nondiscrimination. 1VIZLLRLYZPUULLKVMHYLHZVUHISLHJJVTTVKH[PVU[VJVTWSL[L[OL application process should call 773-702-1032 or email equalopportunity@ uchicago.edu with their request. NRC Research Associateship Programs The National Academy of Sciences, Engineering, and Medicine offers postdoctoral and senior research awards on behalf of 23 U.S. federal research agencies and affiliated institutions with facilities at over 100 locations throughout the U.S. and abroad. We are actively seeking highly qualified candidates including recent doctoral recipients and senior researchers. Applications are accepted during 4 annual review cycles (with deadlines of February 1, May 1, August 1, November 1). Interested candidates should apply online http://sites.nationalacademies.org/PGA/RAP/PGA_046398 Awardees have the opportunity to: • • • • conduct independent research in an area compatible with the interests of the sponsoring laboratory devote full-time effort to research and publication access the excellent and often unique facilities of the federal research enterprise collaborate with leading scientists and engineers at the sponsoring laboratories Benefits of an NRC Research Associateship award include: • • • 1 year award, renewable for up to 3 years Stipend ranging from $45,000 to $80,000, higher for senior researchers Health insurance, relocation benefits, and professional travel allowance DESIRED SKILLS AND EXPERIENCE Applicants should hold, or anticipate receiving, an earned doctorate in science or engineering. Degrees from universities abroad should be equivalent in training and research experience to a degree from a U.S. institution. Some awards are open to foreign nationals as well as to U.S. citizens and permanent residents. ABOUT THE EMPLOYER The National Academies of Sciences, Engineering, and Medicine’s Fellowships Office has conducted the NRC Research Associateship Programs in cooperation with sponsoring federal laboratories and other research organizations approved for participation since 1954. Through national competitions, the Fellowships Office recommends and makes NRC Research Associateship awards to outstanding postdoctoral and senior scientists and engineers for tenure as guest researchers at participating laboratories. A limited number of opportunities are available for support of graduate students in select fields. newscientistjobs.com 31 August 2019 | New Scientist | 47 Join us in Anaheim this November! 2019 ANAHEIM, CALIFORNIA NOVEMBER 13-16, 2019 Recipient of the 2019 AIMBE Excellence in STEM Education Award The Annual Biomedical Research Conference for Minority Students (ABRCMS) is a must-attend event bringing together one of the largest communities of underrepresented minorities in STEM fields. This award-winning conference gathers dynamic undergraduate students, and the research faculty and program directors who mentor them, for four-days of learning, sharing, and networking. From poster presentations to scientific and professional development sessions and exhibitor showcases, ABRCMS is a robust event guaranteed to leave you feeling inspired. Mark your calendar and plan to join us November 13-16, 2019, in Anaheim, CA! www.abrcms.org/register Managed by: Funded by: Fellowships for Postdoctoral Scholars "1_oѲ-uv_brv-u;--bѲ-0Ѳ;|om;ouu;1;m|7o1|ou-Ѳ]u-7-|;vbm7b;uv;-u;-vo=u;v;-u1_ĸrrѲb1-ࢼomvbѲѲ0; accepted from doctoral recipients with research interests associated with the following: Departments - Applicants who wish to conduct research on topics of general interest to one or more of the departments are encouraged to apply. Interdepartmental research, including with the Marine Policy Center, is also encouraged. The Departments are: Applied Ocean Physics & Engineering Biology Geology & Geophysics Marine Chemistry & Geochemistry Physical Oceanography A joint USGS/WHOI aaward will be given to a postdoc whose research is in an area of common interest between USGS and WHOI Scientific Staff. The individual will interact with both USGS and WHOI based advisors on their research. $_;1;-mool";bvlo]u-r_mv|ul;m| Center (OBSIC) will award a fellowship for research on the earth’s internal structure and its dynamic processes vbm]v;-Yoouv;bvlb1l;-vu;l;m|vĺ!;v;-u1_-u;-v bm1Ѵ7;Ĺv;-Yoouv;bvlb1bmv|ul;m|-ঞomķbm1Ѵ7bm]|_; 7;;Ѵorl;m|-m7ņou-rrѴb1-ঞomo=m;v;mvouvĸ;-u|_ v|u1|u;b|_-m;lr_-vbvomvbm]o1;-mŊ0ool seismograph data, including the development and/ ou-rrѴb1-ঞomo=m;-m-Ѵঞ1-Ѵl;|_o7oѴo]b;vĸ ;-u|_t-h;Ŋu;Ѵ-|;7ruo1;vv;vvbm]v;-Yoou v;bvloѴo]-m7ņou];o7;vĸ|_; bm|;urѴ-0;|;;mv;-Yoouv;bvlb1 measurements and oceanographic ruo1;vv;vĸ-m7o|_;uruof;1|v within this broad scope. Award recipients may be advised by v1b;mঞC1v|-@b|_bm|_;C; Departments as well as the USGS, or a 1ol0bm-ঞom thereof. !;1brb;m|vo=--u7v-u;v;Ѵ;1|;71olr;ঞঞ;Ѵķb|_ primary emphasis placed on research promise. Scholarships -u;--u7;7=ouƐѶŊlom|_-rrobm|l;m|vb|_-vঞr;m7 of $61,200 per year, a health and welfare allowance and a lo7;v|u;v;-u1_07];|ĺ!;1brb;m|v-u;;m1ou-];7|oruv; |_;buomu;v;-u1_bm|;u;v|bm-vvo1b-ঞomb|_u;vb7;m| "1b;mঞC1-m7";mbou$;1_mb1-Ѵ"|-@ĺollmb1-ঞomb|_ ro|;mঞ-Ѵ)-7bvouvrubou|ov0lbমm]-m-rrѴb1-ঞom is encouraged. olrѴ;|;7-rrѴb1-ঞomvlv|0;u;1;b;70 1|o0;uƐƔķƑƏƐƖ for the 2020/2021 appointments. Awards bѴѴ0;-mmom1;7bm ;1;l0;uĺ!;1brb;m|vo=--u7v1-m bmbঞ-|;|_;buv|7-m7u;v;-u1_r;ubo7-||_;mvঞ|ঞom-m ঞl;-[;u-m-uƐķƑƏƑƏ-m70;=ou; ;1;l0;uƐķƑƏƑƏĺ u|_;ubm=oul-ঞom-0o||_;"1_oѴ-uv_brv-m7-rrѴb1-ঞom forms as well as links to the individual Departments and their research themes may be obtained through the Academic uo]u-lvv;1ঞomo=|_;);0r-];v-|Ĺ ĺ_obĺ;7ņrov|7o1|ou-Ѵ t-Ѵrrou|mb|ņLul-ঞ;1ঞom lrѴo;u The back pages Puzzles Quick crossword, a riddle of ages and the quiz p52 Feedback Sexy pavement lichen and a robot priest: the week in weird p53 Picture of the week Your photos based on a weekly theme: first up, Mars p53 Almost the last word Readers explain why water hydrates and dogs roll over p54 The Q&A Niamh Nic Daeid on a paradigm shift in forensic science p56 How to be a maker 2 Week 8 How’s the weather? With two micro:bits you can make a mini weather station that sends you up-to-the-minute reports, says Hannah Joshua New stuff you need Second micro:bit and battery DHT11 environmental sensor For next week Large plastic drinks bottle Cardboard Zip ties Servo motor Zip Glue Nuts (the edible kind) Next in the series 1 Moisture-sensing plant 2 Moisture and temperaturesensing plant 3 Plant auto-waterer 4 Tweeting wildlife cam 5 Pest scarer 6 BBQ thermometer 7 Rain alarm 8 Mini weather station 9 Remote controlled pest-proof bird feeder part 1 10 Bird feeder part 2 SENSOR TRANSMITTER MICRO:BIT DAVID STOCK FOR NEW SCIENTIST Hannah Joshua is a science writer and maker based in London. You can follow her on Twitter @hannahmakes LAST week it was rain. This week, our mini weather station will measure temperature and humidity. And by using a second BBC micro:bit, we can get the readings before heading outside. First, we need a DHT11 sensor, and to check whether it works using one micro:bit. To do this, we must teach the MakeCode editor new tricks. Go to “Extensions”, type in “DHT11” and click on the DHT11/DHT22 result. Under the new menu option, select the block that is five lines tall and clip it into forever. This one communicates with the sensor. The default settings are fine. Under that block, clip two “show number” blocks from “Basic” and clip into these two “Read humidity” blocks from the “DHT11/DHT22” menu, using the drop-down to change the first to “Read temperature”. Lastly, add a “pause” from “Basic” to “on start” to give this sensor a moment to fire up before we start quizzing it. Connect the sensor’s Vcc connection to the micro:bit’s 3V pin, its ground to ground and out to pin 0. Attach the battery and check the readings seem sensible for temperature and humidity. Now, we can transmit the data to another micro:bit via radio. In your program, replace the “show number” blocks with two “radio send value name = 0” blocks from the “Radio” menu. Where these say “0”, clip two “round” blocks from “Math”, then into the “0” of each clip a “Read humidity” block from “DHT11/DHT22”, using the drop-down to change the first one RECEIVER MICRO:BIT Make online Projects so far and a full list of kit required are at newscientist.com/maker Email: maker@newscientist.com to “Read temperature”. In the first “name” oval, enter “T:” and put “H:” in the second. Then, clip a 2-second “pause” between the blocks and another “pause” after. The second “pause” will determine how often this micro:bit sends data. I went for 10 seconds. Finally, take “radio set group 1” from “Radio” and clip it into “on start”. The radio group establishes a comms channel so micro:bits using the same one can recognise messages from each other. Now for the receiver. Start a new program and add the same “radio set group 1” to “on start”. Next, grab an “on radio received name value” from “Radio”. Into this, clip a “show string” block and a “show number” block from “Basic”. Then, click and drag the “name” oval from the top of the “on radio received” block and drop it into your “show string” block. Do a similar thing for “value” and “show number”. This code will make your receiver micro:bit show “T:”, followed by the temperature, and “H:” followed by the humidity on the screen. Now, stash your transmitter in a waterproof container and poke a hole so air can get in, but the electronics are safe. The radio range is up to 70 metres in an open area without interference, so get creative with the placement! ❚ 31 August 2019 | New Scientist | 51 The back pages Puzzles Quick crossword #39 Set by Richard Smyth 1 Nihonium, Tennessine, Oganesson – what fourth name is missing from this list? #19 The vicar’s age 3 The ICZN, based in 6LQJDSRUHDQGWKH,$37 EDVHGLQ%UDWLVODYD6ORYDNLD do what? Puzzle set by Zoe Mensch 2 9,192,631,770 what of what equals what? Quick quiz #18 4 A golfball-sized lump of 90 per cent platinum and 10 per cent iridium (by mass) fulfilled what function until 2019? 5 FlyBase collates genetic information concerning which fast-breeding organism beloved of biologists? A bishop visited his friend the vicar on her birthday. Knowing the bishop liked number puzzles, the vicar told him about a family that had just joined her church. “If you multiply their three ages together, you get 2450, and if you add their ages together, you get your own age, your grace.” The bishop, after some thought, said: “I can’t be certain how old everyone in the family is.” The vicar responded: “I am older than everyone in that family.” The bishop could then tell how old everyone was. How old was the vicar on that day? Answer next week Answers below 16 Marriage within a social or ethnic group (8) 18 3LFWXUHSX]]OH 20 6HH'RZQ 21 Harvey ___, rubber tyre pioneer (9) 24 Condition caused by YLWDPLQ'GHILFLHQF\ 25 Of algebra, functions or variables, relating to a 19th-century logician (7) 263DFLILFFOLPDWH phenomenon (2,4) 27$EQRUPDOH[LWRIWLVVXH DOWN 1 B BBHONH[WLQFWGHHU species (5) 2 6RFLDOPHGLDSODWIRUP launched in 2006 (7) 3/2086SDODHRQWRORJLVWDQG essayist (7,3,5) 5 Friedrich ___, inventor of a scale of mineral hardness (4) 6 Air sacs in the lungs (7) 7 õ+DFNWLYLVWöJURXS 10 Fastener patented in 1849 (6,3) 13 2011 science fiction WKULOOHUVWDUULQJ-DNH Gyllenhaal (6,4) 14 Cretaceous clay found in Wyoming (9) 17 Waterproof garment (7) 19%DFWHULDOQHXURWR[LQ 226SLUDOKRUQHGDQWHORSH 236WDU7UHNSKDVHUVHWWLQJ $QVZHUVDQGWKHQH[WFU\SWLFFURVVZRUGQH[WZHHN 52 | New Scientist | 31 August 2019 Cryptic Crossword #13 #18 Cable on the moon Solution Answers A power cable buried in a 1-metre deep trench encircling the moon’s equator will only be about 6 metres shorter than if it was laid on the surface. ACROSS 1%XONLHU5 Umbra, 8 Generation Gap, 96KDUG 10 Trailer, 12 Median, 136WUHVV16 Chimera, 18 Needs, 20 Quadrilateral, 22(SR[\23 Cold War DOWN 1 Bogus, 2 Lanyard, 3 Irradiate, 4 Rotate, 5 UFO, 6 Bagel, 7 Amperes, 11 Antenatal, 12 Macaque, 14 Eyebrow, 15 Garlic, 17 Imago, 196RODU21 Ray Quick quiz #18 Answers 1.0RVNRYLXP7KH\DUHHOHPHQWV added to the periodic table by the ,QWHUQDWLRQDO8QLRQRI3XUHDQG Applied Chemistry in 2016. 2 The International Bureau of :HLJKWVDQG0HDVXUHV %,30 VD\V 9,192,631,770 oscillations of the hyperfine ground states of the caesium-133 atom = 1 second. 3 The International Commission on Zoological Nomenclature and the International Association for 3ODQW7D[RQRP\HQVXUHFRQVLVWHQW animal and plant names. 4 It was the international SURWRW\SHNLORJUDPXQWLOWKH%,30 replaced it with a standard based RQWKH3ODQFNFRQVWDQW 5 The fruit fly Drosophila melanogaster ACROSS 1 Intelligence assessment, purportedly (2,4) 4 Antelope; Chevrolet (6) 8 6SOLWVKDUHG 9 ^ (7) 11 Term used to describe the technological revolution by Harold Wilson in 1963 (5,4) 12 Abnormal growth projecting from a mucous membrane (5) 14 B (5) 15 3HUKDSV RU The radius of the moon (R) at the equator is 1,738,100 metres, but you don’t actually need that figure to answer this question. The length of cable on the surface is given E\WKHIRUPXODë5 Burying the cable 1 metre down reduces the radius to R-1. The new cable length is WKHUHIRUHJLYHQE\ë 5 ZKLFKH[SDQGV WRJLYHë5ë6XEWUDFWLQJWKLVIURPWKH cable length on the surface gives a difference RIëPHWUHV 6RWKHEXULHGFDEOHLVDPHUHPHWUHV shorter than one on the surface. Get in touch Email us at crossword@newscientist.com puzzles@newscientist.com The back pages Feedback Taking a liking to lichen If you happen to be in New Zealand and are unnerved by that man over there apparently licking the pavement, don’t be alarmed. He is probably just after his fill of Xanthoparmelia scabrosa, a grey, leafy lichen commonly found on Kiwi roads and sidewalks. It contains a chemical somewhat similar to the active ingredient in Viagra, gaining it the soubriquet “sexy pavement lichen”. Online marketplaces have taken to selling X. scabrosa by the kilo as a herbal alternative to the little blue pills. Now Kiwi news outlet Newsroom relays warnings from local researchers against likin’ the lichen. Those hoping it will give them more lead in their pencil may get more than they bargain for: the urban pavements where the lichen grow infuse them with high levels of lead and other heavy metals, including cadmium, mercury and arsenic. Perhaps it is fortunate, then, that an investigation by the US Food and Drugs Administration into one online batch of X. scabrosa found it was 20 per cent grass clippings and 80 per cent ground-up Viagra. What dodgy online herbal remedies lack in authenticity, they may make up for in efficacy. Besides, nothing quite kills the mood like popping out to lick the street. Deus Ex Machina A 400-year-old temple in Japan has unveiled its latest priest: a robot modelled on Kannon Bodhisattva, the Buddhist deity of mercy. The $1 million android, named Mindar, leads services at Kodaiji temple in Kyoto, relaying and explaining wisdoms contained in the Heart Sutra. It isn’t the first time holy words have come from robot mouths. Readers may recall that Pepper – a child-sized android that has held down more jobs than Barbie – also had a stint presiding over Buddhist funerals back in 2018. What should we draw from this about the essence of Buddhism, except that creeping automation comes for all, and the holy men won’t be spared? If you pass a saffron-robed man on the street, begging bowl in hand, be kind. He might not even have a job any more. Picture of the week Mars Rabbit run Further to the question of whether nematode worms read New Scientist (10 August), Peter Duffell writes: “On a recent trip to Northumberland we saw a sign in one of the gardens we visited that read ‘RABBITS & HARES KEEP THIS GATE SHUT’.” “If only rabbits and hares are required to shut the gate, what do the rest of us do?” asks Peter. “If we leave them open, do the rabbits and hares get the blame?” Feedback is unsure: rabbits that can read signs can probably type, too. You wouldn’t want to risk online shaming by Northumberland’s literate lagomorphs. Double trouble Let it not be said that Brazil’s president Jair Bolsonaro isn’t environmentally conscious. Yes, he has threatened protections of indigenous land rights and opened up the Amazon to logging and mining. Yes, he fired the director of Brazil’s National Space and Research Institute after it revealed the extent of recent deforestation. But he has a plan. Questioned on his environmental record, he replied: “It’s enough to eat a little less. You talk about environmental pollution. It’s enough to poop every other day. That will be better for the whole world.” As green policies go, two days between number twos is a novel one. We’ll resist the temptation to say it’s all going down the pan. Given the boost Bolsonaro’s policies are giving to consumption and exploitation, Feedback thinks Brazil’s green activists can be forgiven for thinking he is the one full of crap. To give you a taste of our new picture of the week slot, here is New Scientist’s head of features, Rowan Hooper, with a full-size replica of the Curiosity rover. While its twin is on Mars, this one is at the University of Arizona. The next theme is Alexander von Humboldt, in celebration of the 250th anniversary of the naturalist’s birth. Email us your related photos to readerpics@newscientist.com by Tuesday 3 September. Terms and conditions at newscientist.com/pictureoftheweek-terms Noms de flume Wonder weed Such themes lead us, with terrible inevitability, to this week’s dose of nominative determinism. In Adelaide, Australia, Alan Moskwa reveals that a story in The Advertiser on the city’s expanding waistlines has provoked a letter in reply suggesting “toilet bowls and seats should be strengthened, enlarged” and generally made taller and wider. The correspondent’s name? Neil Longbottom. Meanwhile, Peter Jung is delighted to discover that the head of coastal research at Monash University in Melbourne is none other than Ruth Reef. Visiting a chiropodist’s surgery in Greenock, UK, Bill McMillan spies a poster proclaiming that cannabis oil can help with PTSD, epilepsy, Crohn’s disease, cancer, psoriasis, Dravet syndrome “and many more conditions”. Only two weeks ago, this esteemed organ raised an eyebrow at the wondrous variety of claims made for weed’s curative powers (17 August, p 20). But Bill is most perplexed by an omission. “It seems the oil can cure anything except foot and toenail issues,” he says. Well, the chiropodists wouldn’t tell you if it did. ❚ Got a story for Feedback? Send it to New Scientist, 25 Bedford Street, London WC2E 9ES or you can email us at feedback@newscientist.com 31 August 2019 | New Scientist | 53 The back pages Almost the last word Why don’t blue highlighters look as bright as the other colours? Seven litres a day How does water hydrate us? If we drink a lot of it we only pass it as excess waste. Andrew Sanderson Spennymoor, County Durham, UK We lose water in four principal ways: in urine, sweat, breath and faeces. This doesn’t include minor losses such as in tears and spitting. We gain water by drinking, and by breaking down food during metabolism into carbon dioxide and water. Sweat, breath and faeces stay at the same concentration, so the main control of body fluid content is via our kidneys. Their activity is controlled by a molecule known as vasopressin or antidiuretic hormone, which is secreted by the pituitary gland. This is regulated by an area of the brain called the hypothalamus, which contains receptors sensitive to the blood’s concentration of sodium and other substances. The kidneys are the main way for us to excrete salts. If you eat a lot of salt, your kidneys will increase the concentration of the urine up to their maximum ability. Past this, the volume will increase. If you drink a lot of water, 54 | New Scientist | 31 August 2019 Why do dogs and horses roll on their backs when happy? DOUGLAS SACHA/GETTY Eleanor Horton, Canterbury, Kent, UK Breaking down food – and our metabolism in general – generates waste. This needs to be removed or it would damage the body. Water is the solvent for these waste products – it dissolves them and allows them to pass out of the body as urine, as well as in sweat. Urine is produced in the kidneys and consists of urea and other waste products dissolved in water. We need to drink more water to replenish the fluid that leaves the body this way. When you are dehydrated, your urine will be dark yellow. This is because there isn’t enough water in your system to dilute the urea sufficiently. Water itself is not a waste product – it is a mechanism by which the body removes waste. Roll of honour This week’s new questions In the ink Why do blue highlighter markers never seem to have the high luminosity of pink, yellow, orange and light green highlighters? Ana Beard, London, UK Once upon a time Why does my brain like fictional stories? Shvets Roman, Moscow, Russia Run the world If the world’s population all met in one place and all ran in the same direction, would this affect Earth’s rotation? Neil Edwards, Guildford, Surrey, UK urine concentration falls and volume increases. The more you exercise and sweat, the more salts you lose, because sweat can’t be concentrated, hence the marketable value of sports drinks. The amount you need to drink is unique to you. Linked to the hydration sensors are the thirst parts of your brain. If you feel thirsty, then drink water. Otherwise, keep someone else happy and rich by buying their fluid replacement and by all means carry a bottle with you to prove that selective advertising has an effect on you. Brian Pollard North Hill, Cornwall, UK The human body is made up mainly of water, and our physiology operates to keep within about a litre of the 45 or so litres in an average-sized person. The way it does this is by regulating the feeling of thirst. When the fluid level starts to get low, your body makes you feel thirsty. You drink, and the body’s regulatory system works out how much you should drink to restore the balance to be within required limits. When you have drunk enough, you feel sated and stop drinking. This system is remarkably efficient. It takes several hours for the fluid levels in the body to respond to the liquid you have drunk, but the regulatory system works well enough most of the time to keep the body’s fluid content within its typical parameters. If you lose a lot of water quickly, on a very hot day for example, you may lose too much, and then you become dehydrated, and it feels unpleasant. The unpleasant feeling is your body requesting an urgent ingestion of liquid. David Muir Edinburgh, UK Horses roll and writhe on their backs not because they are happy but because they want to get rid of an itchy irritation. They could be trying to get rid of their winter coat, which makes them sweaty in the summer. If they are being bothered by biting insects, then rolling in mud, or even dust, affords some protection. Dogs are different. A very relaxed dog will lie on its back with its vulnerable abdomen exposed. On the other hand, a dog that is frightened may roll over as a sign of submission and thus avoid attack by another dog. Some dogs retain their evolutionary urge to roll in other animals’ excreta, such as fox faeces, to disguise their own scent. This seems to make dogs happy and their owners very unhappy. Tony Holkham Boncath, Pembrokeshire, UK Horses, and many other animals, roll to rid themselves of irritation or parasites that they can’t reach with their mouths or feet. It is necessary, but leaves the animal vulnerable for a short time. Dogs roll for this reason too, especially because many modern breeds are unable to groom themselves effectively. They also do it to submit to another member of the pack and, in domesticated dogs at least, because they love to have their belly rubbed. My Jack Russell Sparky would probably put this last reason at the top of the list. ❚ Want to send us a question or answer? Email us at lastword@newscientist.com Questions should be about everyday science phenomena Full terms and conditions at newscientist.com/lw-terms The back pages The Q&A As a forensic scientist, Niamh Nic Daeid does research that helps justice be done – from how fires start to how DNA transfers between objects As a child, what did you want to do when you grew up? My parents were practical scientists, and they used their skills to solve real-world problems. Partly as a consequence of that, my overriding desire was to make a difference when I grew up. Explain what you do in one easy paragraph. I lead a team of people from different scientific, statistical and science communication backgrounds and we try to address some of the fundamental challenges in how science is used in the justice system. We work with police, researchers, lawyers, judges and the public. I also do forensic casework – my area of expertise is in investigating how and where fires start. What’s the most exciting thing you’re working on right now? We are working on the development of a global citizen science project that will help forensic scientists understand how materials transfer between surfaces and then persist on the surface they have transferred to. We have designed and tested universal experiments to build databases that will address these questions and will launch these globally in 2020. These are profoundly important issues that help us explain the relevance and weight of forensic evidence to our courts. If you could send a message back to yourself as a kid, what would you say? Work harder than everyone else and don’t be afraid to think differently. Were you good at science at school? Yes – and maths and woodwork, which is always a useful skill to have. What achievement or discovery are you most proud of? Proving that conventional smoke alarms don’t wake children and then finding a sound that does. It sounds like a truck reversing, that intermittent beeping noise, followed by a female voice saying “get up, the house is on fire”. Each sound is played for 10 seconds, repetitively. Most children wake with either the first beeping tone or when they hear the voice for the first time. 56 | New Scientist | 31 August 2019 How has your field of study changed in the time you have been working in it? We have been at the centre of a paradigm shift in forensic science. The situation before was that the only time judges and forensic scientists spoke to each other was in the courtroom. Now, the judiciary and forensic scientists work together. We speak about science in informal ways, exploring each other’s questions and perspectives, to gather a collective understanding of what science can answer and what it can not. Do you have an unexpected hobby, and if so, please will you tell us about it? Not really – I am a workaholic. How useful will your skills be after the apocalypse? I can make things out of wood and I can set a fire almost anywhere – two of the essential skills for building a shelter and keeping toasty warm. If you could have a long conversation with any scientist living or dead, who would it be? One is Michael Faraday, who wrote The Chemical History of a Candle and instigated the Royal Institution’s Christmas lecture series. Another is Florence Nightingale, who was the first female member of the Royal Statistical Society and made good use of infographics. OK one last thing: tell us something that will blow our minds… We have very little understanding of how trace materials, such as DNA, transfer and persist from one surface to the next. If someone picks up a glass that you have handled and then they pick up a weapon and assault someone, your DNA could transfer to that weapon even though you have never directly touched it. We are undertaking research to understand whether this can happen and in what circumstances. ❚ Niamh Nic Daeid is professor of forensic science and director of the Leverhulme Research Centre for Forensic Science at the University of Dundee, UK STOCK MONTAGE/GETTY “Your DNA could transfer to a weapon even though you have never directly touched it” Travel Insurance with you in mind Travel insurance designed by travellers Up to £10M medical expenses Available for UK/EU Citizens if you’re already abroad Cover for cameras and gadgets available Extreme sports and activities covered, including trekking and winter sports Get immediate cover truetraveller.com or call 0333 999 3140