EARTH. FOUR BILLION YEARS AGO

TURMERIC IN EVERYTHING Are spices really that good for you? HIGGS CRISIS The particle is perfect, and that's a problem MICROBIOME CSI How your personal bacteria can give you away WEEKLY 16 June 2018 EARTH. FOUR BILLION YEARS AGO We re homing in on the moment life began BEYOND QUANTUM There s an even weirder theory out there PLUS IN PRAISE OF WESTWORLD / VEGAN CLOTHES/ BAOBAB MYSTERY No3182 4.50 US/CAN$6.99 9 770262 407282 2 4

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CONTENTS newscientist.com/issue/3182 Management Executive chairman Bernard Gray Publishing director John MacFarlane Finance director Jenni Prince Chief technology officer Chris Corderoy Marketing director Jo Adams Strategy director Sumit Paul-Choudhury Human resources Shirley Spencer Non-executive director Louise Rogers Publishing and commercial Customer services manager Gavin Power HR co-ordinator Serena Robinson Facilities manager Ricci Welch Executive assistant Sarah Gauld Trainee PA Emily Perry Receptionist Alice Catling Display advertising Tel +44 (0)20 7611 1291 Email displayads@newscientist.com Commercial director Chris Martin Richard Holliman, Justin Viljoen, Henry Vowden, Helen Williams Recruitment advertising Tel +44 (0)20 7611 1204 Email nssales@newscientist.com Recruitment sales manager Mike Black Key account managers Martin Cheng, Reiss Higgins, Viren Vadgama US sales manager Jeanne Shapiro Marketing Head of marketing Lucy Dunwell David Hunt, Chloe Thompson, Andrew Wilkinson Web development Maria Moreno Garrido, Tuhin Sheikh, Amardeep Sian New Scientist Live Tel +44 (0)20 7611 1273 Email live@newscientist.com Creative director Valerie Jamieson Sales director Jacqui McCarron Event manager Henry Gomm Conference producer Natalie Gorohova UK Newsstand Tel +44 (0)20 3787 9001 Newstrade distributed by Marketforce UK Ltd, 2nd Floor, 5 Churchill Place, Canary Wharf, London E14 5HU Syndication Tribune Content Agency Tel +44 (0)20 7588 7588 Email tca-articlesales@tribpub.com Subscriptions newscientist.com/subscribe Tel +44 (0)330 333 9470 Email ns.subs@quadrantsubs.com Post New Scientist, Rockwood House, Perrymount Road, Haywards Heath, West Sussex RH16 3DH Volume 238 No 3182 On the cover 35 Turmeric in everything Are spices really that good for you? 10 Higgs crisis The particle is perfect, and that s a problem 12 Microbiome CSI How your personal bacteria can give you away 30 Earth. Four billion years ago We re homing in on the moment life began 28 Beyond quantum There s an even weirder theory out there Plus In praise of Westworld (42). Vegan clothes (22). Baobab mystery (9) ALAMY News and Technology The Higgs field really does give mass 10 Leaders 5 The latest bandwagon may not save the planet. We shouldn t let technology damage football News 6 THIS WEEK X-ray bomb to destroy chemical weapons. Trump meets Kim. Hedgehog calamity 8 NEWS & TECHNOLOGY CRISPR cancer fear. Exoskeleton helps people walk. Diamonds solve a space mystery. Africa s ancient baobabs are dying. Higgs does what it should and that s a problem. Parkinson s link to gut bacteria. Criminals can be identified using microbes. AI building planner. Drones to spot festival violence. Your 4-year-old prefers shoes to sick people. Sleepy seals. Organics on Mars may be from ancient life 19 IN BRIEF Acne treatment that works. Jupiter s whistling lightning. Football matches in miniature on your table. Elusive whales tracked Analysis 22 INSIGHT Why ditching fur and leather for plastic alternatives is an ethical minefield 24 COMMENT Trump and Kim s power plays. Is space tourism ready for lift-off at last? 25 ANALYSIS The unknown virus that could be the next pandemic Features 28 Beyond quantum There's an even weirder theory out there 30 Where it all began The epic hunt for life's origin on Earth 35 Turmeric in everything Should we swallow the hype about spices? 40 The video-assisted ref's a... Will replay reviews make football refereeing decisions any better? Culture 42 Violent delights As Westworld s robots go off-script, we re hooked 43 New expectations Discover the scientific side of Charles Dickens PLUS: This week s cultural picks 44 Open your mind A new era of psychedelics needs a great guide Regulars 26 APERTURE Robot s open-head surgery 52 LETTERS The sun can solve water shortages 55 MAKE Smart table, dumb waiter 56 FEEDBACK Macarena and medicine 57 THE LAST WORD Light at the limit DANIEL DOMINGUEZ/CERN 16 June 2018 NewScientist 3

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LEADERS Editorial Editor Emily Wilson Managing editor Rowan Hooper Art editor Craig Mackie Editor at large Jeremy Webb News Chief news editor Niall Firth Editors Penny Sarchet, Jacob Aron, Timothy Revell, Jon White, Chelsea Whyte Reporters (UK) Andy Coghlan, Jessica Hamzelou, Michael Le Page, Clare Wilson, Sam Wong, (US) Leah Crane, (Aus) Alice Klein Features Chief features editor Richard Webb Editors Catherine de Lange, Gilead Amit, Catherine Brahic, Julia Brown, Daniel Cossins, Kate Douglas, Alison George, Joshua Howgego, Tiffany O Callaghan, Sean O Neill Feature writer Graham Lawton Culture and Community Editors Liz Else, Mike Holderness, Simon Ings, Frank Swain Subeditors Chief subeditor Eleanor Parsons Tom Campbell, Hannah Joshua, Chris Simms Design Kathryn Brazier, Joe Hetzel, Dave Johnston, Ryan Wills Picture desk Chief picture editor Adam Goff Kirstin Kidd, David Stock Production Mick O Hare, Melanie Green, Alan Blagrove, Anne Marie Conlon Contact us newscientist.com/contact General & media enquiries Tel +44 (0)20 7611 1202 enquiries@newscientist.com UK 25 Bedford Street, London, WC2E 9ES Tel +44 (0)20 7611 1200 AUSTRALIA Level 11, Suite 3, 100 Walker Street, North Sydney, NSW 2060 Tel +61 (0)2 9422 8559 US 210 Broadway #201 Cambridge, MA 02139 Tel +1 617 283 3213 2018 New Scientist Ltd, England New Scientist is published weekly by New Scientist Ltd. ISSN 0262 4079. New Scientist (Online) ISSN 2059 5387 Registered at the Post Office as a newspaper and printed in England by William Gibbons (Wolverhampton) Beware the bandwagon The way to a good life doesn t lie in trends and easy answers WHEN it comes to the pressing environmental issues of the day, we are all aware that we need to do our bit. The rise of veganism shows that we are increasingly thinking about how our lifestyle affects not only our own health, but also the world around us. Unfortunately, jumping on the latest bandwagon is not always the way to save the planet. While research published in Science has again shown that ditching meat and dairy from your diet is one of the best ways to reduce your environmental footprint, the same isn t true of your wardrobe. It turns out that vegan-friendly alternatives to fur and leather, as seen on display at Australia s recent Fashion Week (above), can harm sea creatures, because they are made of that other pervasive ecovillain: plastic (see page 22). The evidence is not yet clear, but some animal fabrics may be the least harmful choice overall. Such unintuitive outcomes crop up again and again when we try to make ethical lifestyle choices. As New Scientist has reported, ditching disposable plastic bags for a fetching cotton tote only pays off after you have used it 131 times, due to the large environmental burden of cotton which is also an issue for clothes. Turning to our cars, biofuel, Beauty in imperfection SWEET disorder, the poet Robert Herrick wrote, is more bewitching to the human eye than precise art. What he applied to Elizabethan fashion sense applies equally to football, whose World Cup is just kicking off in Russia. It will be the first one to supplement on-pitch decisionmaking with officials viewing video-replay footage, officially only in cases of clear and obvious error (see page 40). After all, football is big business: decisions must be right and seen to be right. This magazine is mostly as resolute as a solid centre back in defence of technology, but here not so much. The beautiful game s majesty, and ability to sustain many a heated half-time dispute, lies in the dodgy offside, the seen as a greener alternative to petroleum, leads to deforestation and increased carbon emissions (see page 20). Also, burning wood instead of gas to heat our homes results in greater air pollution. The rush to follow trends without proper evidence is similarly apparent in the rise of the turmeric latte and other spice-based cure-alls. Despite some of these provoking masses of research, the findings often don t add up to the hype (page 35). So what should we do? Looking for evidence may not be the most fashionable choice, but in the long run, it is the only one worth making. disallowed goal, in the bit of argybargy when the ref s not looking. When the onward march of artificial intelligence takes from us the means of making our daily bread (a scenario that available facts and the long history of shonky AI admittedly make less than certain) all we shall have are circuses. With these, let s not also subjugate human autonomy to the tyranny of tech and the endless video replay. Let s see sweetness in football s disorder. DAVID MOIR/AAP/PA 16 June 2018 NewScientist 5

THIS WEEK Building an X-ray bomb The US is working on new technology for destroying chemical weapons STAFF SGT.JOHN STRONG/USAF David Hambling THE US Department of Defense wants to build an X-ray bomb. The unusual device could knock out chemical and biological weapon sites without spreading hazardous material over a wide area, as is the risk with the explosives currently used. In April, when the US, UK and France struck facilities associated with chemical weapons in Syria, like labs and training centres, they had to be careful not to hit any storage sites. Although hightemperature incendiary warheads have been developed that should neutralise any chemical and biological weapons they hit, there is still a risk that a stray missile could instead damage a facility and cause it to leak. To try to avoid this risk in the future, the US Department of Defense is working on using a Existing warheads could neutralise chemical weapons with an add-on strong burst of X-rays to render chemical and biological weapons useless, without damaging the vessels containing them. The Department of Defense has contracted specialist electronics company Hyperion Technology Group to develop a prototype. The device will fit inside an existing warhead casing, on a bomb or a missile. The idea is that, at high enough exposure levels, X-rays destroy bacteria, spores and other biological agents. X-rays would also break down complex molecules like organophosphate nerve gases, such as sarin. However, a simple gas like chlorine would be unaffected. A dose of X-rays is measured in a unit called Grays. A recent study from the Singapore Institute of Manufacturing Technology found that doses of less than 13 Grays could activate bacterial spores like anthrax rather than killing them, so higher levels of radiation would be needed. Around 10,000 Grays would be enough to destroy stored anthrax spores, according to a previous study from the US Department of Energy. For comparison, a normal chest CT scan is less than 0.01 Gray. X-ray intensity decreases rapidly with distance, so the weapon would have to get very close to the target. Anyone nearby would receive a fatal dose of The idea is that a strong enough burst of X-rays would wipe out bacteria, spores and nerve agents radiation, causing failure of the cardiovascular and central nervous systems. The technology could potentially be used as a terror weapon, says Robert Bunker at the US Army War College s Strategic Studies Institute, in Pennsylvania. This technology could be utilised against human beings to cause injuries and fatalities stemming from its radiation sickness effects, says Bunker. He points to the case of Glendon Scott Crawford, who was convicted in 2016 of attempting to build an X-ray weapon to expose people to lethal doses of radiation from a truck. However, Bunker says the bomb would probably be designed so that the technology powering it incinerated on impact, to avoid others getting hold of it. Under international law, a weapon is legal if it does not cause any unnecessary suffering. This means the use of an X-ray bomb would not necessarily be unlawful if it is the only way to achieve a lawful military objective, says Marco Roscini at the University of Westminster in London. The technology behind the bomb is not publicly available, but the Department of Defense has previously experimented with ways of converting explosive energy into an X-ray pulse for a similar purpose. Using an explosion to rapidly compress matter, such as helium and aluminium, a team in the US was able to produce extremely high pressure normally found only inside stars. Under these conditions, rather than binding together with outer electrons as normal, the inner electron shells of adjacent atoms may bind together. These highenergy bonds are unstable and when they break they produce energetic radiation such as X-rays. It is not known whether this technology is the basis of the current project. Work on the project will commence in July and run for two years. The US Department of Defense did not respond to New Scientist s request for comment. 6 NewScientist 16 June 2018

For new stories every day, visit newscientist.com/news Is this time different? KEVIN LIM/THE STRAIT TIMES/HANDOUT/GETTY IMAGES IN A handshake watched around the globe, US President Donald Trump finally met North Korean leader Kim Jong-un on Tuesday in Singapore. Now, the world awaits to see what concrete actions might follow. The pair signed a document pledging to work towards complete denuclearization of the Korean Peninsula. Analysts have cautioned this does not mean that Kim will be willing to unilaterally give up his nuclear weapons without the US also removing its protective nuclear umbrella from South Korea. But Trump seemed to suggest Kim would do exactly that. He s de-nuking the whole place, Trump said after their summit. I think he s going to start now. The document makes no mention of how to verify the dismantling of North Korea s arsenal a sticking point for past agreements. Trump suggested that international observers would be involved, but gave no specific details as to how this difficult task would be accomplished. It takes a long time, scientifically, said Trump about verification at a post-summit press conference. We will do it as fast as it can mechanically and physically be done. Trump claimed that North Korea has already destroyed a missile engine testing site. For his part, Kim noted the surreal nature of the meeting. Many people in the world will think of this as a form of fantasy, from a science-fiction movie, he said through a translator. For more on the power dynamics between the two leaders, see page 24. Opportunity stuck in epic Mars storm IS THIS Opportunity s last stand? NASA s long-lived rover is weathering a Martian dust storm the likes of which no rover has ever seen. The aptly named Perseverance valley, where Opportunity is hunkered down, is cloaked in enough dust to blot out the sky and make daytime as dark as night. Less than 0.01 per cent of the sunlight at Mars is currently reaching the rover s solar panels. Because the rover runs entirely on solar power, NASA has put it into minimal operations mode in the hope of keeping it warm enough to prevent damage to its batteries. Opportunity s twin, Spirit, is thought to have succumbed to the extreme cold of Martian winter after it got stuck in soft soil in 2010. The storm spans more than 18 million square kilometres, an area larger than North America and equivalent to about 12 per cent of Mars s surface. It is not clear how long the tempest will last, but dust storms on Mars often go on for weeks or even months. ALIK SIMMONS Hedgehogs are on the wane in Britain THEY recently topped a poll to become the UK s favourite mammal, but hedgehogs are in steep decline. The UK agency Natural England and the charity the Mammal Society have just issued the results of the most thorough census since 1995 of the 58 mammals native to Britain. They found the number of hedgehogs had plunged to 522,000, a two-thirds drop since 1995. This is one of the largest losses we saw, says John Gurnell at Queen Mary University of London. Hedgehogs should now be classed as vulnerable in Britain, he says. Gurnell says a doubling in badger numbers over that time may be one factor: badgers eat hedgehogs and compete for the same insect prey. Others include hedgerow loss with more intensive farming, and pesticide exposure via hedgehogs food. They seem to be doing better in urban areas, says Gurnell hedgehogs thrive in untidier gardens. In all, populations of 15 mammals grew, nine fell and four held steady. The rest could not be reliably counted. US net neutrality is finally dead AFTER months of public outcry and legal wrangling, a US law controlling the sale of internet access has officially been repealed. The net neutrality rules, introduced by president Barack Obama in 2015, required internet providers to treat all web content equally. This meant that companies couldn t pay extra to have their web pages, apps or services load faster, making the internet a level playing field for all. But the Federal Communications Commission said the laws were stifling innovation and so voted in December 2017 to repeal them. This change came into effect on 11 June. FCC commissioner Jessica Rosenworcel, who voted against the change, released a statement that said: This is bad news for all of us who rely on an open internet for so many facets of civic and commercial life. All may not be lost. Several US states have brought in laws enshrining the principles at a state level. The European Union introduced net neutrality laws in 2016. 16 June 2018 NewScientist 7

NEWS & TECHNOLOGY Gene editing stem cells has cancer risk EMBRYONIC stem cells could help treat all kinds of disorders, and editing the genomes of these stem cells could make the treatments far more potent. But there might be a catch. A team at Novartis has found that genome editing kills most human embryonic stem cells and the ones that survive are more likely to have mutations in a key anticancer gene. Cells with such mutations are, in theory, far more likely to turn cancerous. This is something we need to be aware of and test for, says Florian Merkle at the Wellcome- MRC Cambridge Stem Cell Institute in the UK, who wasn t involved in the work. Embryonic stem cells (ESCs) are derived from embryos or created by reprogramming adult cells. They can turn into any cell type in the body, so they have potential for treating a range of diseases, from Parkinson s to diabetes. Genome editing could make such therapies even more powerful. For instance, if a person has a disease caused by a specific mutation, ESCs could be derived from their cells in the lab, the mutation corrected and healthy tissues returned to the body. But when Ajamete Kaykas s team at the Novartis Institutes for Biomedical Research in Boston tried to use the CRISPR geneediting technique on ESCs, most of the cells died. The researchers found that the deaths were due to a protein called P53 (Nature Medicine, doi.org/cqtc). P53 s role is to prevent cancer by triggering cell suicide when it detects dangerous mutations. It appears to have kicked into action because the gene editing process induces mutations by cutting a cell s DNA. What is worrying is that the cells that survived were far more The stem cells that survive gene editing are more likely to have mutations in a key anticancer gene likely to have mutations in the gene that codes for p53. If geneedited ESCs with a faulty p53 were turned into rapidly dividing cells like skin cells and implanted in the body, they could acquire even more mutations and turn cancerous. The risk would be lower if ESCs were turned into non-dividing cells such as neurons. Other researchers are surprised by the results. I m inclined to believe this study but I still have some questions, says Merkle. In particular, DNA breaks occur in cells all the time, so it s not clear why those made by CRISPR should produce such a strong cell-suicide response in ESCs. Another question is whether this happens in other cell types. The good news is that we may already have solutions. Biologists have developed advanced forms of CRISPR that don t completely sever DNA strands. These would not trigger the problem, says Robin Lovell- Badge at the Francis Crick Institute in London. It should also be standard Embryonic stem cells can become any type of cell in the body practice to check cells grown in labs for p53 mutations, says Merkle. His team showed last year that such mutations occur surprisingly often even in ESCs that haven t been edited. This could skew research done with the cells into genetic disorders. No clinical trials involving gene-edited ESCs have begun. A firm called CRISPR Therapeutics plans to treat beta-thalassemia and sickle cell disease by editing each individual s blood stem cells. On 30 May, it announced that this trial had been put on hold by regulators, for reasons that haven t yet been made public. Michael Le Page BSIP SA / ALAMY STOCK PHOTO Self-balancing exoskeleton helps people walk again A SELF-BALANCING exoskeleton that enables people with lower body paralysis to walk is being tested in France. Many exoskeletons require the wearer to use crutches at the same time, but this one maintains its own balance to help mimic a person s natural gait. The exoskeleton, called Atalante, is made by Paris-based company Wandercraft. It has two movable legs and a back rest, all of which have straps that wrap around the user. To walk, the wearer moves their hips. This movement is picked up by an array of sensors, which then enact the desired motion by controlling 12 joints across the hip, knee and ankle. One of the biggest difficulties is making sure the exoskeleton maintains balance even during unexpected events, like missing a step or receiving a push. If we are falling forward we need to put a foot in front of us, says Matthieu Masselin at Wandercraft. To solve this problem, Atalante has algorithms that constantly assess the exoskeleton s position and speed, as well as taking into account the measurements of the user such as The exoskeleton was tested in initial trials in 2017 WANDERCRAFT weight, height and the length of various leg segments. Floriane Vintras at Wandercraft, who uses a wheelchair because of a neurological disease, tested Atalante during initial trials in 2017. She was able to use the suit to walk for several hours without pain. Standing up was a magnificent experience, she says. Twelve people with paraplegia from spinal cord injury are involved in clinical trials that are running across two rehabilitation centres in France. Each wears the exoskeleton while walking, standing, sitting down and performing various balance exercises. Frances Marcellin 8 NewScientist 16 June 2018

For new stories every day, visit newscientist.com/news Tiny spinning diamonds solve an old cosmic puzzle NANODIAMONDS may have dispelled a mystery that has puzzled astronomers since 1996. That s when something weird turned up in data from the COBE satellite, which was launched in 1989 to study cosmic background radiation left over from the big bang. COBE saw microwaves at frequencies of 10 to 60 gigahertz, but no clear source. The favoured explanation had been tiny specks of carbon-rich grains. They are made of polycyclic aromatic hydrocarbons, or PAHs, and are abundant in the clouds around young planet-forming stars. What s more, the grains act as dipoles they have north and south poles like a magnet and this allows them to emit microwaves when spinning fast. But stars where PAHs were detected did not always emit the distinctive signal, casting doubt on the idea. Now Jane Greaves at Cardiff University, UK, and her colleagues have scanned dust clouds around 14 bright young stars that are up to a million years old, plus those of 30 older stars like our sun. They saw the unusual microwave signal coming from just three of the young stars and none of the older ones. From these three stars alone, they also detected infrared emissions that matched what we would expect from bits of diamond less than a nanometre across (Nature Astronomy, doi.org/cqsj). No one had discussed or thought about nanodiamonds being the source before, says Greaves. Her team calculates that the odds of this being a coincidence are vanishingly small. They re little pyramids of carbon atoms with hydrogen atoms poking out the top, and so [they] are dipoles. When molecular collisions cause them to spin millions of times per second, they would emit microwaves, she says. Not everyone is convinced. My money s still on the PAHs and related things, particularly nitrogencontaining PAHs, says Louis Allamandola at NASA Ames Research Center in California. Andy Coghlan Twilight of the African baobabs Michael Le Page AROUND 500 BC, in what is now Zimbabwe, an elephant defecated after feasting on baobab fruits. A seed sprouted in the dung. The resulting tree grew for nearly 2500 years. Over that time, the Roman Empire fell, the Kingdom of Zimbabwe grew and foundered, and British colonisers came and left. The Panke baobab was the oldest flowering tree in the world until 2010 when it collapsed and died. It is not the only one of these venerable trees to die of late. In the past 12 years, nine of the 13 oldest baobabs in Africa, and five of the six largest, have died. Climate change is the chief suspect. The loss of the largest and oldest baobabs is a wake-up call for the dramatic climate change which has started to affect many areas of the world, especially southern Africa, says Adrian Patrut of Babes-Bolyai University in Romania. His team estimates that the number of baobabs in Africa has halved since 1960. We believe that the African baobab should be considered endangered, he says. I m really shocked, says Thomas Pakenham, author of the 2004 book The Remarkable Baobab. It would be a great tragedy if they are dying off. In 2005, Patrut s team in South Africa set out to study the growth patterns of the African baobab (Adansonia digitata). It is the One village had a funeral for its baobab when it died, calling it the mother of us all and thanking it longest-lived and largest of all flowering trees: the volume of its wood can reach 500 cubic metres. However, there are bigger or longer-lived non-flowering trees, notably giant sequoias and bristlecone pines. Patrut s team studied and dated around 60 of Africa s oldest baobabs. As they worked, however, many trees died. The HOUGAARD MALAN/NATUREPL.COM Baobab trees at a national park in Botswana oldest parts of the 2100-year-old Dorslandboom in Namibia fell over and died in 2006, as did those of the 2000-year-old Glencoe tree in South Africa in 2009. Botswana s 1400-year-old Chapman tree perished in 2016. It s not just the oldest baobabs that are dying. We found many young and medium-aged baobabs fallen and dead, especially in southern Africa, says Patrut. There was an outbreak of a disease called black sooty bark mould between 2000 and 2010, he says. However, most of the dead trees showed no signs of infection (Nature Plants, doi.org/ cqsh). Instead, the team attributes the deaths to the climate becoming more extreme not just hotter, but with more intense droughts and floods. The loss of old trees is bad for people and wildlife. Large trees provide shelter, food and water the baobab s thick trunks are essentially moisture-packed sponges. People traditionally use almost every part of it, from the edible fruit and leaves to the bark and roots, containing fibres that are used to make ropes, baskets and clothes. In his book, Pakenham mentions one village holding a funeral for its baobab when it died. They addressed it as the mother of us all, he says, and thanked it for protecting them in times of drought. The problem is not just that the older trees are dying, but that fewer young trees are sprouting. The seeds germinate best when eaten and dispersed by animals like elephants, says Patrut. But there are now few large animals outside protected areas. Nevertheless, African baobabs grow fast, so if more were planted the species might bounce back. If you want to help, buy foods made from baobab fruits, says Patrut. This may encourage people to plant new trees. 16 June 2018 NewScientist 9

NEWS & TECHNOLOGY The Higgs works but still baffles Richard Webb WE WERE expecting it but it has only deepened the enigma. Experiments at the Large Hadron Collider at CERN near Geneva, Switzerland, found that the Higgs boson really does give all other fundamental particles mass. The new measurements, by the ATLAS and CMS collaborations, have seen the Higgs, discovered at CERN in 2012, being produced along with both a top quark and its antimatter equivalent, a top antiquark. It follows the discovery by both groups of the Higgs boson decaying directly into tau leptons, heavier cousins of the electron (arxiv.org/abs/1708.00373). Both measurements are based on five years of data. Interactions between the Higgs and the top quark are particularly key, as the top is the most massive fundamental particle. At 172 gigaelectronvolts, it dwarfs even the Higgs s own mass of 125 GeV. So whatever the Higgs does, it does it more with the top. It drives why the universe is like it is, says Fabio Cerutti of ATLAS. But it s really puzzling: we don t understand why the top mass is so heavy. The results suggest the interaction between the Higgs and the top quark is just as predicted by the standard model, our best description of how particles and forces interact (arxiv.org/ abs/1806.00425). The tau lepton The Higgs field, seen in an artist s impression, really does give mass DANIEL DOMINGUEZ/CERN results are similarly in line. Together, they are the first direct indication that interactions with the Higgs boson explain why fermions, the class of particles that make up matter, have the masses they do. Understanding the Higgs mechanism could help explain the stability and structure of matter around us. Subtle differences in the masses of up and down quarks explain why neutrons within the atomic nucleus are heavier than protons, and so why stable atoms can form. Similarly, the mass of the electron sets the size of atoms, and so determines how chemistry works. The top quark measurements are another bittersweet triumph for the standard model, says Jon Butterworth of the ATLAS team. It is one of the benchmark processes we knew we had to see as part of the health check of the standard model, he says. And that health is disgustingly good. Disgusting, because we know the standard model is incomplete. It leaves open essential questions on the make-up of dark matter, which is more than two-thirds of all matter, and why matter apparently dominates antimatter in the universe. Every time we see something that agrees with the standard model, that means we don t know the answers, he says. Any deviation would be a clue, and we want clues. Parkinson s link to virus that kills good gut bacteria A VIRUS that kills a good form of gut bacteria could trigger Parkinson s disease. This viral attack might cause a chain reaction of nerve damage, leading from the digestive system to the brain. Parkinson s disease is a progressive disorder causing tremors and trouble with moving. It is known to involve the death of nerve cells in the brain, linked with the misfolding of a protein found in nerve fibres called synuclein. Although Parkinson s is seen as a brain disorder, a recent suggestion is that the misfolding starts in nerves in the gut, triggering a domino effect up the nerve fibres to the brain. But it is unclear what starts the changes to synuclein. George Tetz of the Human Microbiology Institute in New York thinks gut microbes might be responsible. After analysing existing data on the gut microbes of 31 people with Parkinson s disease and 28 people without the condition, his team found that the biggest differences were in the abundance of dairy bacteria such as Lactococcus species, and the viruses that prey on them. The viruses, called bacteriophages, invade the bacteria, reproduce inside them and then burst out, killing them. The people with Parkinson s disease had twice the levels of these viruses and just one-tenth the level of Lactococcus. Most likely this is more than a coincidence, says Tetz. The differences could not have Those with Parkinson s had more of the virus and less of the bacteria than those without the disease been caused by Parkinson s medication because the patients had all been recently diagnosed and had yet to start treatment. But the finding isn t clear-cut. For example, last year another group analysed the same microbiome data using a different technique. They found differences in other species but not in Lactococcus. And it is unclear whether microbial changes cause the nerve damage that leads to Parkinson s or are a consequence of it. The findings were presented at the ASM Microbe conference in Atlanta, Georgia, last week. Clare Wilson 10 NewScientist 16 June 2018

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NEWS & TECHNOLOGY Microbes give away criminals Chris Baraniuk THE sneakiest burglars slip by unnoticed, but they still leave millions of witnesses at every crime scene. Researchers have found a way to identify criminals based on the microbes they shed from their skin or nostrils. Jarrad Hampton-Marcell at Argonne National Laboratory in Illinois and his colleagues showed in 2014 that people leave a unique microbial signature in their homes. This implied that microbes could also be used to identify suspected criminals like burglars. What if we could potentially find signatures that are unique to each individual? says Hampton-Marcell. He first visited crime scene investigators in Florida. They explained how burglars generally enter homes and told him that local law enforcement responses vary from minutes to hours. In 2016 and 2017, Hampton- Marcell and his colleagues arranged for 45 undergraduates to carry out mock burglaries at 10 homes in Illinois and Florida. The researchers then swabbed for microbe deposits. Points of entry were very fruitful. They re going to be using force, moving, likely shedding their microbiome, says Hampton-Marcell. Finally, the team analysed microbes from the skin and nostrils of every burglar, using a genetic marker to distinguish the various strains. After sampling the participants and gathering data from other studies, the researchers found they could group together thousands of unique sets of microbes that served as microbial fingerprints for individual people. Ultimately, they could identify which mock burglar had entered each property with greater than 70 per cent accuracy. I flipped out, says Hampton-Marcell. I literally fell out of my chair. The research was presented at the ASM Microbe conference in Atlanta, Georgia, last week. It s an exciting step forward, Even the most careful burglar leaves living clues behind WESTEND61/GETTY IMAGES says forensic scientist Claire Gwinnett at Staffordshire University in the UK. Like other forms of trace evidence such as DNA, the microbial data could help show that a burglar has rummaged around in a specific item like a jewellery box, she says. However, there are obstacles to using the technique in criminal investigations. During the 2014 study, the occupants of one home left it empty for a few days. In that time, their microbial signature vanished. So unlike a fingerprint, warns Hampton-Marcell, the microbial signature left by a criminal will decay starting just 30 minutes after they leave. But if samples can be collected fast enough, that decay may also reveal when a crime happened, says Ruth Morgan at University College London. Is there some way of determining the age of the deposit? That s potentially a really valuable way of reconstructing events around a crime, she says. Hampton-Marcell wants to get the accuracy of identification up to at least 90 per cent. That would help, says Morgan, but she says even 70 per cent accuracy could be useful if DNA and fingerprint evidence were also available. I can see how this, in combination with other forms of evidence pertinent in a specific case, could be an incredibly useful toolkit, she says. AI works out the fastest way to put up buildings YOU VE heard of groundbreaking algorithms, but what about algorithms breaking ground? An AI system that can plan the construction of buildings is being piloted on several projects in the US, in the hope that it will speed up work. The system, called Artificial Intelligence Construction Engineering or Alice, can digest a 3D model of a proposed building and spit out a detailed schedule for how it should be constructed. This includes specifying in what order particular structures need to be fitted together, such as ceilings to walls, or when specialist tools, such as cranes, need to be on-site. Around 20 US companies as well as a major property group in Thailand are now trialling Alice. It s a breakthrough in our minds, says Ricardo Khan at Mortenson, a large US construction firm currently testing Alice on three multimilliondollar projects in Chicago and Seattle. In a pilot last year, the firm used the technology to plan a schedule for a hospital in Denver, Colorado. As the building had already started, it only partially implemented the proposed plan. But doing so still helped to cut construction time by a couple of weeks, says Khan. The system works by coming up with hundreds of millions of potential ways to assemble a building. These are generated in as little as a day. The system works by coming up with hundreds of millions of ways to assemble a building Alice then chooses a tiny handful of those schedules that could work based on certain parameters, such as how many cranes are available at particular locations or the project s cost limitations. Firms using Alice have to feed it recipes of how they typically construct certain things, from walls to columns. But once this is done, the system automatically works out how those components slot together, a bit like puzzle pieces, says René Morkos, CEO of Alice Technologies, the Californian firm behind the AI. Chris Baraniuk 12 NewScientist 16 June 2018

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NEWS & TECHNOLOGY Drones to spot festival violence Abigail Beall A DRONE surveillance system can identify when someone in a crowd is acting violently. The artificial intelligence-based technology will be tested at a science festival in India later this year. The system assesses the way each person in a crowd is moving via two cameras on the drone. At the moment, it can recognise punching, stabbing, shooting, kicking and strangling. However, once the technology goes on sale, whoever buys it will be able to input their own definition of a violent act, says Amarjot Singh at the University of Cambridge, who built the system with two colleagues based at science institutes in India. To teach the software what a violent act looks like, the user moves computer-generated stick people on a screen to mimic the different actions they want the drone to recognise. In initial tests, the system was 94 per cent accurate at identifying real violent acts from footage. However, as more people appear in frame, it became less accurate, falling to 79 per cent accuracy when looking at 10 people at once (arxiv.org/abs/1806.00746). The system will be tested in October at Technozion, a science and technology festival at the National Institute of Technology in Warangal, India. The festival is attended by around 3000 to 4000 people and is extremely packed, says Singh. However, there are concerns about both the test and the technology. Why is this being The surveillance system can recognise punching, stabbing, shooting, kicking and strangling DAVID JENSEN/PA It is tough to monitor big crowds at festivals like Glastonbury trialled at college festivals in India rather than at Glastonbury or Coachella? says Malavika Jayaram, a cyberlaw researcher at Harvard University and a fellow of the Centre for Internet and Society in India. She suggests it may be because it is legally and socially easier to get approval. Violence can t be described by such a basic set of motions, she says. Therefore technology like this is unlikely to accurately catch all violent acts. As what constitutes a violent act can be defined by the system s owner, there is also the threat of misuse. What if this tech is used by non-democratic regimes to identify dissidents? Or by gangs to identify enemies? says Gemma Galdon Clavell, who works on the ethics of technology at the University of Barcelona in Spain. The system is an example of imperfect science attempting to enact the fantasy of a perfect society, says Jayaram. Even if the accuracy rates were higher, is this the kind of society we want to build? Singh certainly thinks so. AI can help develop powerful surveillance systems which can assist in identifying pernicious individuals, which will make society a safer place, he says. Most 4-year-olds prefer shoes to sick people DO YOU care more about beetles or people who are ill? Your answer probably depends on your age, since your moral compass gradually shifts from early childhood to adulthood. As we get older, we increasingly value other human beings over plants, animals and inanimate objects, according to research led by Karri Neldner at the University of Queensland, Australia. Her team showed 24 pictures to 151 children aged between 4 and 10, asking them to place the people and things they cared about most in an inner circle, those they cared about a little in a middle circle and those they didn t care about at all in an outer circle. All age groups placed pictures of their mum and best friend in the inner circle, but there were differences in how younger and older children rated other humans. For example, 4-year-olds tended to care less about teachers and police officers than they did about dogs, monkeys and rose bushes. They showed even less interest in sick people, rating them lower than beetles, plates and shoes (PLoS One, doi.org/gdmcsw). In contrast, 10-year-olds tended to care more about a range of humans, particularly those who are ill or who have disabilities. This is more in line with the moral values of adults, which have been tested in previous studies. As we get older, our awareness of the distinctions between humans and other animals grows, says Neldner. Children may care less about sick people because they haven t yet grasped the concept of pain, says Neldner. Over time, our experiences of sickness and pain help build empathy with others, she says. We are driven to help or care for sick people because we recognise that we ourselves would want the same treatment, she says. Another finding was that children of all ages placed less importance on people from different racial backgrounds. For example, Caucasian children typically placed Chinese people in their outer circles. Neldner says the study helps to identify prejudices that it might be possible to tackle with education. Her team now plans to see if children s moral values vary across cultures. It s likely that every cultural upbringing will have its own unique influence on our preferences for what we care about, she says. Alice Klein 16 June 2018 NewScientist 15

NEWS & TECHNOLOGY Seals hold clue to REM sleep Sam Wong ONE species of seal sleeps in a way never seen in any other animal. Their odd habit may help explain REM (rapid eye movement) sleep, the form of slumber when we have our most vivid dreams. REM sleep is so named because humans move their eyes back and forth during it, under shut eyelids. This phase of sleep seems to be essential for the health of most mammals. For example, if rats are deprived of it, they lose weight and eventually die. Cetaceans like dolphins are an exception. Half their brain sleeps at a time, so they can remain vigilant. Studies have found no sign of REM sleep in cetaceans. Seeking more exceptions, Jerome Siegel at the University of California, Los Angeles, and his colleagues looked at northern fur seals. They are semi-aquatic, living mostly in the sea except during the breeding season. The team gave four captive seals implants that recorded brain activity, allowing them to track sleep states. The seals had access to a dry platform, but the team removed it for 10 to 14 days at a stretch to simulate time at sea. On land, in addition to slowwave non-rem sleep, the seals had 80 minutes of REM sleep a day. In the water, however, REM sleep fell to just 3 minutes a day on average (Current Biology, doi.org/cqqw). Unlike any animal studied, the fur seals sometimes slept with their whole brain, and sometimes with just half like dolphins. The proportion of half-brain sleep varied from 62 per cent on land to 94 per cent in water possibly to watch out for predators like orcas. After being deprived of REM sleep, most mammals get extra sleep to catch up. But the fur seals showed little or no rebound back on land. They also showed no apparent ill effects from going without REM sleep. The most popular explanation for REM sleep is that it is involved in long-term memory storage, but Siegel says there is lots of evidence against this. Some antidepressant drugs suppress REM sleep with no apparent impact on memory. Reviewing data on how other mammals sleep, the researchers found that time spent in REM HOBERMAN COLLECTION/UIG VIA GETTY When you sleep with the fishes, it s wise to keep half your brain awake sleep correlates with the amount of non-rem sleep. But in species that don t sleep with their whole brain, REM sleep is absent. To explain this, they propose that REM sleep helps regulate brain temperature. When the entire brain is in non-rem sleep it cools, so REM may be needed to warm it back up, preparing the animal for waking. Previous studies have found that animals, including humans, are more alert when woken after REM sleep than non-rem sleep. Thomas Wehr at the National Institute of Mental Health in Maryland first put this idea forward in 1992. This article adds to the story, says Wehr. Animals that are perfectly capable of producing REM sleep dispense with it, for as long as some part of the brain is kept warm by the waking state. Brain warming may be relevant but probably isn t the whole story, says John Lesku at La Trobe University in Melbourne. If the function of REM sleep were only to modestly increase brain temperature, then one wonders why we would not just wake up [from deep sleep], he says. This might suggest that REM sleep serves other functions unrelated to brain warming. Mars has organic material that may be from ancient life MARS is full of organic molecules that life needs to thrive. NASA s Curiosity rover has found methane seeping up from the ground in summer, and more complex organic molecules preserved in Martian clay for 3.5 billion years. Most carbon-containing molecules are classed as organic. Some have turned up on Mars before, but none as sophisticated as those newly found in the clay of a dried lakebed. These are complex organic molecules that we think were floating around in a lake on Mars over 3 billion years ago and that we can pick up and examine today, says Kirsten Siebach at Rice University in Texas. The molecules could have arrived on meteorites, or volcanic processes could have formed them. There is also a chance they came from living organisms (Science, doi.org/cqq2). Even if they didn t, they could have been food for microbes on ancient Mars. The molecules have lasted so long that any such microbes, if they existed, could be similarly preserved. Curiosity also examined methane in the Red Planet s atmosphere. Chris Webster at NASA s Jet Propulsion Laboratory in Pasadena, California, and his team found a seasonal cycle, with more methane in Martian skies during each hemisphere s summer. In the model that best fits the fluctuations, the methane starts deep underground and wends its way to the surface through pores and fissures These are complex organic molecules we think were floating in a lake on Mars over 3 billion years ago (Science, doi.org/cqq3). But how it got underground is still a mystery. It is possible that the methane is linked with the other organic compounds. You might have this organic material at depth, going through various processes and forming methane which vents to the surface, says Jennifer Eigenbrode at NASA s Goddard Space Flight Center in Maryland. Are there organisms that are doing those processes? Is it life? There is a laundry list of non-biological processes that could produce organic molecules on Mars. But life isn t off the table yet. Leah Crane 16 NewScientist 16 June 2018

NEW SCIENTIST D S CO V E RY C u t t i n g - e d g e J a p a n : f r o m T o k y o t o O k i n a w a Explore the diverse faces of Japan. Journey from buzzing Tokyo to snow-capped mountains; from hot springs to subtropical coral reefs DEPARTURE: 4 NOVEMBER 2018 TOKYO HAKONE KYOTO OKINAWA 11 days from 4995 per person TECHNOLOGY AND INNOVATION OUTSTANDING NATURAL BEAUTY TAKE PART IN RESEARCH Begin your adventure in futuristic Tokyo. Visit the University of Tokyo and enjoy a talk from a robotics designer on campus. Experience the awe-inspiring Miraikan, Japan s Museum of Emerging Science and Innovation, before heading for the stunning scenery around Hakone. In the shadow of Mount Fuji, visit the volcanic Owakudani valley and walk between steam vents and hot springs. Then catch the bullet train to Kyoto and explore its peaceful temples and lavish gardens where bamboo thickets crowd the skyline. Round off your trip with three days on the subtropical island of Okinawa. Get stuck in at the Okinawa Institute of Science and Technology where you ll take part in environmental research, learn about sustainable living and how coral is being restored. SPEAK TO OUR SPECIALIST TEAM AT STEPPES TRAVEL TO FIND OUT MORE Visit newscientist.com/travel/japan or call +44 (0)1285 600 129

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IN BRIEF NASA/JPL-CALTECH/SWRI/MSSS/KEVIN M. GILL Jupiter s lightning helps map its water stores THE Juno spacecraft has collected data from lightning strikes on Jupiter that may help us figure out where the planet stores its water, and how much there is. That is because lightning in gas giants is believed to come from clouds of water, like it does on Earth. When the Galileo probe dove into Jupiter s atmosphere in 1995, it found much less water than was expected. It s become evident that the probe fell into a dry spot in the atmosphere, says William Kurth at the University of Iowa, who worked on two studies to map Jupiter s lightning. It seems most of that missing water is in the Kidney cancer uses immune cells tricks CANCEROUS kidney cells have brought us a step closer to grasping how cancers spread to form potentially fatal secondary tumours. Sakari Vanharanta of the Medical Research Council Cancer Unit at the University of Cambridge and his colleagues found that in order to spread, kidney cancer cells exploit a gene that healthy white blood cells use to roam around the body. Comparing the cells of human kidney cancers, the researchers found that those with the ability to spread had increased activity in two regions of the genome. These act as accelerator pedals, boosting the activity of nearby genes. These enhancers influence a gene known to help white blood cells move around the body and into organs to fight infections. planet s northern hemisphere, with some in the south and almost none at the equator. Past Jupiter probes have only detected lightningrelated radio waves at frequencies a million times lower than Earth s highest-frequency lightning. But Juno got a much-closer look than previous spacecraft. During its first eight orbits, in 2016 and 2017, its microwave radiometer detected 389 lightning signals at the higher frequencies we see from Earth s lightning (Nature, doi.org/gdk2ws). Another instrument detected more than 1600 lower-frequency lightning strikes called whistlers because their pitch falls, like a slide whistle, as they travel. There were typically one to 30 of these flashes per square kilometre per year Earth has about six flashes per square kilometre per year (Nature Astronomy, doi.org/cqpg). The gene was up to 20 times more active in kidney cancer cells that could spread than in ones that couldn t (Cancer Discovery, doi.org/cqp6). Silencing these enhancers in kidney cancer cells stopped them from spreading when injected into mice. Vanharanta believes other types of cancer may also spread by stealing other cells tricks. It might be possible to stop cancers spreading by targeting these enhancers, he says. Mini footballers on your dining table MILLIONS will watch the upcoming football World Cup on TV screens around the globe. But what if you could enjoy a mini virtual reconstruction of each match on your dining table instead? To create such an experience, Konstantinos Rematas and colleagues at the University of Washington in Seattle trained a machine learning algorithm to convert 2D YouTube clips into 3D reconstructions. An augmented reality headset, like Microsoft s Hololens, lets a viewer see the match on a flat surface in front of them. They see small holograph-like players running around, which they can then walk around or move closer to (arxiv.org/abs/1806.00890). There are some limitations, though. The ball has not been properly rendered yet, and the side of each player not facing the camera is currently missing. Thieving whales filch tonnes of fish SPERM whales are tracking fishing boats off the coast of Alaska and nabbing fish from the lines. It now seems they take about 5 per cent of the fishing industry s annual quotas. Lone sperm whales harass boats in the east of the Gulf of Alaska. When they target a boat, they work fast to pick fish from the hooks, often without even being seen. Megan Peterson at Sierra Nevada College and her colleagues tracked the whales impact on the Alaskan sablefish fishery over 27 years. They found that one whale can take a quarter of a ship s catch in one go. They may return many times an hour. This means a $5 to $8 million annual loss for Alaska s $100-million sablefish industry (Fisheries Research, doi.org/cqqr). 16 June 2018 NewScientist 19

IN BRIEF For new stories every day, visit newscientist.com/news ADEK BERRY/AFP/GETTY IMAGES Europe burns palm oil in its cars BAD news for the rainforests of Malaysia and Borneo: palm oil use in the European Union rose 7 per cent in 2017 compared with 2016. Global demand for palm oil is driving the clearance of these rainforests to make way for more plantations. EU consumption grew even as the use of palm oil in foods and cosmetics fell slightly. The increase was almost entirely due to the rising use of biodiesel made from palm oil. Around 51 per cent of the palm oil used in the EU is burned in cars and trucks, according to figures from data company Oilworld. Another 10 per cent goes on heating and electricity. Foods and cosmetics account for just 39 per cent. EU laws effectively stipulate that normal diesel must be blended with biodiesels made from vegetable oils, and palm oil is the cheapest kind. Yet the EU s own studies show that using palm oil as a biofuel increases rather than decreases greenhouse emissions. Burning palm oil in cars and trucks to meet Europe s green energy targets must be the single stupidest thing we do in climate policy, says Laura Buffet of Transport & Environment, which campaigns for cleaner transport. In January, the EU s Parliament voted to stop using palm oil as a biofuel, but the final decision rests with the European Commission. Elusive whales reveal their secrets in their wakes WE KNOW little about some of the world s largest animals, the elusive beaked whales. But we may soon find out how many species there are, by sequencing the DNA they leave in their wake. Beaked whales can be 12 metres long but we rarely see them because they spend so much time up to 3 kilometres underwater. There are 23 known species, including one found in 2016 that has not been formally described. There may still be some new species out there, says Scott Baker of Hatfield Marine Science Center Acne treatment with no side effects A NOVEL anti-acne cream is better at clearing pimples and gentler on the skin than existing lotions. Acne begins when Cutibacterium acnes bacteria feed on excess oil in the skin and release inflammatory molecules that cause angry, red pustules. Jeffry Stock at Princeton University and his colleagues wondered if blocking this inflammation could prevent pimples. They tested a new antiinflammatory compound called SIG1459 with 65 volunteers who had mild to moderate acne. Each participant tried one of three seemingly identical creams: a placebo, SIG1459 or benzoyl peroxide a common treatment that often causes skin redness, dryness and stinging. Those using SIG1459 cream saw a 77 per cent reduction in acne severity, compared with 56 per cent for those using benzoyl peroxide (Experimental Dermatology, doi.org/cqp8). One of the biggest advantages of SIG1459 is that it doesn t cause any side effects, says Eduardo Perez at Signum Biosciences, the firm developing the cream. That suggests it will be a major improvement for acne sufferers. in Oregon. Much of what we know is from recordings of the sounds they make, which are thought to be unique to each species. Some of these species have never been seen alive, says Baker. His team has now shown that they can identify beaked whale species from the DNA they leave behind in the water. Such environmental DNA is becoming a useful source of data. However, Baker s team is the first to use it to identify large animals like whales in the open sea. The whales DNA can be Sour tastes linked to risky choices MOST don t like to take chances when it comes to out-of-date food. But a study suggests that a mouthful of sour milk might increase your appetite for risk-taking. Marianna Obrist at the University of Sussex, UK, and colleagues looked at how the five main flavours affect risk-taking. Seventy volunteers sipped a drink of plain water, or water flavoured to be salty, sweet, sour, bitter or savoury umami. Immediately after, they played a video game, in which they inflated a balloon by clicking on it. Each click brought a monetary reward, but the detected up to 2 hours after the animals have swum through. It comes from the cells shed when they spout, defecate or slough off old skin. Whales are pretty leaky organisms, says Baker. So far, the team can sequence only one kind of DNA, called mitochondrial DNA. This is enough to identify a species, but not individuals. The study is not yet published, but the team did publish a proofof-principle study on orcas in April (Frontiers in Marine Science, doi.org/cqkc). pot was wiped out if the balloon burst. Participants who sipped sweet and umami flavours seem to have more conservative strategies, with fewer balloons bursting overall. Those who sipped a sour drink were the riskiest gamblers, clicking 40 per cent more than the sweet drinkers (Scientific Reports, doi.org/cqp9). Obrist says she doesn t know why sour flavours might do this, but our sense of taste has been linked to a range of cognitive effects, such as predicting personality traits and influencing our social behaviour and working memory. SAM DIEPHUIS/GETTY 20 NewScientist 16 June 2018

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INSIGHT VEGAN CLOTHES What not to wear Ethical consumers are increasingly turning against animal products like fur and leather, but plastic imitations aren t guilt-free either, says Alice Klein AT AUSTRALIA S recent Fashion Week, fur coats were everywhere, but not a single animal was harmed in their making they were all synthetic. We ve never seen this many fashionistas get on board with this particular trend, said Finder, an Australian fashion website. The fad is part of a global backlash against animal-derived textiles like fur, leather, wool and silk last week, the UK s Labour party pledged to ban fur imports. Driven in part by the growing evidence of Australian shearers kicking, hitting and cutting sheep. On the other hand, proponents of animal-based textiles say their longevity and biodegradability makes them environmentally friendly. The International Council of Hides, Skins and Leather Traders Association notes that these materials are based on natural, renewable resources. So are the likes of fur and leather really better for the environment? To provide some clarity, the Sustainable Apparel Coalition a global collective of environmentally minded fashion brands created the Higg Materials Sustainability Index in 2012. It scores textiles based on the amounts of energy, water and chemicals that go into their production, and the pollution and greenhouse gases that result. A higher score means the material is worse for the environment (see Time for a new look?, right). Vegan fabrics, despite being kinder to cows and sheep, may unwittingly be harming ocean creatures vegan movement, people are choosing to buy plastic imitations made from materials like polyester and acrylic instead. That may seem like the obvious ethical choice, but plastic comes with its own set of problems. These materials are derived from non-renewable petroleum, don t biodegrade and can shed harmful microfibres into the oceans. We ve got these two uber issues animal welfare and overconsumption of plastic that are coming up against each other, says Clara Vuletich, a sustainable fashion consultant based in Sydney. On one hand, many peoples say that exploiting animals for their skin and fur is cruel, so favour plastic alternatives. And the problem could run deeper: a recent investigation by animal welfare organisation PETA, for instance, claimed to have found A model struts his faux-fur stuff at Australia s recent fashion week DAVID MOIR/AAP/PA IMAGES; RIGHT: NAT-2 22 NewScientist 16 June 2018

For daily news stories, visit newscientist.com/news According to the index, cow leather, for example, is worse than synthetic polyurethane leather, since it scores 161 versus 59. This is because cow farming is a major source of greenhouse gas emissions and leather tanning uses toxic chemicals. In contrast, kangaroo leather scores 29 because it is made from the skin of wild kangaroos and has no farming-related carbon footprint. One major limitation of the index, however, is that it only evaluates the environmental impact of textiles during their production, says Lisa Heinze at the University of Sydney. It doesn t consider how we use clothes or what we do with them at the end of their life, she says. Microfibre mess For instance, polyester scores more favourably than sheep wool because less energy goes into its production. But a wool coat may ultimately have a smaller environmental footprint than a polyester fur because it is likely to last longer and will biodegrade when it is eventually discarded. Once a synthetic jacket ends up in landfill, it s never going to break down, says Heinze. Moreover, wool doesn t leach plastic microfibres into oceans, she says. The environmental impact of such fibres is only just starting to be understood. It began to attract widespread attention in 2016, when researchers at the University of California, Santa Barbara, showed that polyester fleece jackets release up to 2 grams of microfibres per washing machine cycle. A team at Plymouth University, UK, later showed that a standard load of acrylic or polyester clothes could release more than half a million microfibres in a single wash. Since these aren t fully removed by water treatment, they can be ingested by marine life and damage their digestive tracts. Researchers at the University of California, Davis, recently found that one-fifth of fish sold at their local fish markets contained plastic clothing fibres. That means that vegan fabrics, despite being kinder to cows and sheep, may unwittingly be harming ocean creatures, says Heinze. It s a completely messy issue. One option is to wash synthetic clothes in a mesh laundry bag designed to trap loose microfibres. Another is to look for clothing that is both animal and plastic-free, says Gordon Renouf, co-founder of Good On You, an ethical fashion app. Several fashion brands are experimenting with using faux leather made from plants, for example. UK vegan footwear label Bourgeois Boheme uses Piñatex leather, which is made from the leaves of pineapple plants. A machine pulls long fibres out of the leaves, which are then compressed and treated to make the material. The texture is more leather-like than synthetic leathers it s softer and more pliable, says Heinze. One square metre of Piñatex is made from about 480 leaves the waste from 16 pineapples and costs 18 per square metre, compared with 20 to 30 for the same amount of cow leather. Similarly, German brand Nat-2 just launched sneakers (pictured LAB FASHION The ultimate guilt-free look may be grown in the lab. New Jersey-based company Modern Meadow, for example, makes realistic-looking leather from yeast cells in a dish. The cells are genetically engineered to produce collagen the protein that gives animal skins their structure which is then pressed into sheets and tanned using an environmentally friendly process. Because the firm has complete control over how the sheets are made, it can offer a wide range of weights, textures and other properties, says a spokesperson. The bioleather won t be commercially available until 2020, The Higg Materials Sustainability Index scores textiles based on the environmental costs of production, but it doesn t count the impact of how we use them Alpaca wool Cow leather Silk Cotton Sheep wool Polyurethane leather Nylon Acrylic Polyester Kangaroo leather Non-vegan 29 59 56 48 41 above right) made of mushroom leather. These are much more expensive, selling for 525. The material is extracted from tinder sponge, a fungus that grows on birch trees. The fungus is harvested by hand, dried for up to one year, and then peeled by hand. Other companies are but it has already been used to make a T-shirt that went on display at the Museum of Modern Art in New York in October 2017. Even up close, it is hard to tell it apart from the real thing. At the same time, VitroLabs, a start-up in California, says it is working on growing fur from stem cells, although it hasn t released any details yet. Then there is Bolt Threads, another Californian team, which has produced silk from genetically engineered yeast cells. The company started selling a tie made out of its lab-grown silk last year, and is now working on other types of apparel in collaboration with designer Stella McCartney and outdoor clothing brand Patagonia. 81 Vegan 99 128 161 A higher score is worse for the environment 281 This shoe is made from mushrooms (really) trying to grow real leather and fur in the lab, so that no animals are harmed (see Lab fashion, below). However, for some types of clothing, animal and plastic-free options are hard to find, says Vuletich. Your winter coat, for example, is most likely made from wool, leather, feather down or polyester. Maybe you could go for a thick, quilted cotton jacket, but even then, cotton farming typically uses a lot of water and pesticides, says Vuletich, which isn t great for the environment. High-tech materials may one day solve these issues, but until then, consumers must choose between animal-derived and synthetic clothes, says Vuletich. It really comes down to you and what your values and priorities are, she says. Renouf agrees. Maybe you are more moved by animal issues, or maybe you care more about environmental issues it s up to you as a shopper to decide what s more important. 16 June 2018 NewScientist 23

COMMENT Power plays Donald Trump and Kim Jong-un have played a risky game of nuclear bluff. Has their summit helped, wonders Christopher Boehm TAUNTS over nuclear buttons between North Korea s Kim Jong-un and US President Donald Trump galvanised efforts to set up the historic meeting between the two that took place this week. That earlier spat in January also had an unanticipated consequence. Not long afterwards, Russia s Vladimir Putin, ranking second on the world s nuclear political stage, announced a new type of intercontinental rocket. A simple animation showed a weapon that would supposedly renew the nuclear arms race as it sped across the globe, presumably to kill millions of Americans. It seemed slightly pointless, given that mutually assured destruction has been with us for over half a century. But what Putin understood, viscerally, was that if you wanted to keep your hand in politically, you had to make the same sort of chimp-like alphamale bluffs that preceded the announcement of the historic summit between Trump and Kim. The US stands willing to pay for a huge military budget, with its close nuclear allies the UK, France and Israel. Russia, China plus India and Pakistan make up the rest of the nuclear group. Kim has been watching these players. He understands there is a dominant elite and surely wants to join it. But he also recognises that to do so, he needs to deal with Trump s nuclear dominance by being able to dispel any doubt that he could hit US cities. North Korea s track record might suggest that Kim thinks he can buy time to fully develop that capability even if his bluffs suggest it is already there through insincere negotiation tactics, perhaps dragging out implementation of an eventual deal on denuclearisation. Space tourism is go? Civilian trips into space sound close, but we have been here before, says Paul Marks IT EMERGED last week that SpaceX has postponed a muchvaunted tourist trip around the moon from this year to late 2019 at the earliest. So what should we make of Virgin Galactic founder Richard Branson s declaration that he is just months away, not years from venturing into space aboard SpaceShipTwo, the company s eight-seat suborbital spaceplane? Branson drove home the idea of an imminent breakthrough by telling the BBC his firm is now in a neck and neck race with Blue Origin, the nascent space tourism business run by Amazon founder Jeff Bezos, to be the first to carry passengers. We have heard such predictions before: Virgin Galactic was originally slated to begin ferrying tourists to space by 2008. Talk of mass space tourism followed its spaceship design partner, Scaled Composites, winning the $10 million Ansari X-Prize in 2004, as the first commercial venture to put an astronaut into suborbital space twice in a few days using the same craft. But that success with its singleseat craft of which Virgin s Richard Branson has declared that he is just months away, not years from venturing into space SpaceShipTwo is a bigger version hasn t led to the kind of fast-paced commercialisation that followed similar prizes offered in the early days of aviation. For instance, when Charles Lindbergh scooped the $25,000 Orteig prize after crossing the Atlantic in his monoplane in 1927 the effect on commercial aviation was rapid and electrifying. It persuaded people that aircraft could be safe. As a result, the beginnings of the mass transit civil aviation system quickly began to take shape. This hasn t been repeated with space flight; no civilian has yet taken a paid trip to suborbital 24 NewScientist 16 June 2018

For more opinion articles, visit newscientist.com/opinion Trump for his part has stood by, watching Kim and President Moon Jae-in of South Korea do a reunification dance that stunned the world and raised the noble idea of ending a bitter war on the Korean peninsula. With a chance to take centre stage, Trump will have seen the meeting with Kim as an opportunity to make his standing at home less unfavourable. Psychologist Steven Pinker, best known for his book on the arc of human aggression as our species has advanced, called The Better Angels of Our Nature, has identified lessening violence as a tendency. However, the nuclear age brought the potential to dramatically upend that trend. Kim and Trump, with Putin trying to cut in, introduced a new degree of risk in a precarious world, and the high-stakes stage where this is played out must be watched. Active nuclear bluffing became a public tool, and such behaviour carries real dangers. Did the better angels of our nature really get a chance to come to the fore in Singapore on 12 June? Let s hope so. Christopher Boehm is a professor of biological sciences and anthropology at the University of Southern California, Los Angeles, and a director of the USC Goodall Research Center space. Space is a very different venture from aviation and public angst isn t so easy to allay. Escaping Earth s gravity is still full of risk and eye-wateringly expensive. A fatal crash during testing of the first SpaceShipTwo prototype, in 2014, put flights back further still. Civilian space flight still awaits its Lindbergh moment, a feat that, at a stroke, engenders such public confidence in the reliability and safety of commercial rocketry that space tourism takes off big time. Just don t bet too much on it happening any time soon. Paul Marks is a technology, aviation and spaceflight writer based in London REUTERS/PA IMAGES ANALYSIS Nipah virus The deadly disease you ve never heard of Debora MacKenzie NIPAH virus has killed 17 people in the southern Indian state of Kerala. It is a relatively small toll, from a virus few know about. The outbreak began last month and now seems under control. But there has been a global shudder among disease experts. Many consider Nipah the scariest of the emerging viruses since the Ebola epidemic of 2014. It is one of eight viruses the World Health Organization deems a priority for vaccine development. The Kerala outbreak shows why. Nipah had never been seen there, and it is 2600 kilometres from any previous known human outbreaks. The death rate may now exceed the 75 per cent average of Nipah in Bangladesh. Worse, the virus may be learning to fly. Nipah virus was discovered in a Malaysian town of that name during an outbreak in 1998, when 105 people died of a mysterious brain inflammation. Research revealed that fruit bats carry the virus without getting sick, then infected pigs via half-eaten fruit, who gave it to people. In 2004, Nipah struck western Bangladesh when people drank palm sap contaminated by infected fruit bats. There has been an outbreak there nearly every year since, and two have occurred in nearby parts of India. The Bangladesh strain of the virus caused the Keralan outbreak, and seems more worrying. There was almost no transmission between humans in Malaysia and the virus infected the lungs in just a few cases, says Daniel Lucey of Georgetown University in Washington DC, but that has changed. In Bangladesh, pneumonia and cough are much Many consider Nipah the scariest of the emerging viruses since the Ebola epidemic of 2014 more common and there is also some person-to-person transmission. That transmission is what matters. To cause an epidemic, each infected person must give the pathogen to more than one other, on average. Nipah achieves only 0.48. But some people appear to infect far more, suggesting the virus can up its game. We don t yet know how that happens. Nipah, like Ebola, usually The burial of a man who died of Nipah virus last month in Kerala spreads through bodily fluids yet some cases, says Lucey, seem to have spread via airborne droplets. If Nipah evolves to do that more often, it could more readily cause an epidemic. The good news is that after the recent Ebola outbreak, a shaken global health community began cataloguing worrying viruses, including Nipah, and boosting the search for treatments. The effort meant one treatment, a specific anti-nipah antibody made in Australia, was quickly sent to Kerala, says Marie-Pierre Preziosi of the WHO. It arrived after the virus was contained, but India is keeping it for next time. And days after India diagnosed the outbreak, the Coalition for Epidemic Preparedness Innovations, also set up in the wake of the Ebola epidemic, gave US vaccine companies $25 million to test and produce a Nipah vaccine. The grant had already been planned and there should soon be more, says CEO Richard Hatchett. Nipah, like Ebola, tends to strike small numbers of poor people unpredictably, so vaccines are hard to test and there is little economic incentive to develop one. The coalition aims to counter that. It is a race with the virus. Nipah has been seen in fruit bats in at least 10 Asian and African nations, says Lucey, who fears an urban outbreak that could allow Nipah to adapt to people. A vaccine will come none too soon. 16 June 2018 NewScientist 25

APERTURE 26 NewScientist 16 June 2018

Open-head surgery AS SOON as you see one, you get a chill down your spine, says Will Jackson at Engineered Arts, the UK firm behind these spookily realistic androids. The Cornwall-based company makes robots for high-profile events such as film or TV launches, as well as for tourist attractions such as Madame Tussauds. Boasting face-tracking software, speech recognition, state-of-the-art animatronics and body parts ranging from rudimentary feet (bottom right) to lifelike eyeballs, its creations often have people doing a double take. The robot pictured being assembled is Fred, a character inspired by the TV show Westworld (for our review of season 2, see page 42). As a publicity stunt, robot Fred was left in a London pub and would strike up conversations with people as they went past. What are your thoughts on the impending humanoid robot invasion? he asked one punter. You can imagine a range of possible replies, depending on the proximity to closing time. Just basic speech and some subtle movements are enough to give an unnerving sense that the robot is alive. However, animatronics still has a long way to go before it is truly convincing, before robots can escape the uncanny valley. There is nothing that matches human muscle, says Jackson sophisticated motors just can t cope with the range of movement we are capable of. You are just left gobsmacked by the mechanics of the human body. Timothy Revell Photographer Matt Cardy/Getty Except top left: Engineered Arts Ltd 16 June 2018 NewScientist 27

BIG IDEA I HAVE a confession to make: I m bored of quantum mechanics. This is an odd thing for a physicist to admit, but the most successful theory of modern physics has started to leave me cold. Perhaps I have just grown too used to its spooky predictions and its love of randomness. Or it might be the fact that, despite its many successes and the way it has captured popular imagination, there are hints that quantum mechanics isn t as accurate a picture of reality as some would have you believe. What really excites me is the idea that it might be no more than an approximation for some deeper, more intriguing theory lying just out of reach. The evidence? There are fundamental questions that quantum mechanics just can t answer, and theoretical predictions that violate its premises. Coming to terms with such a theory, if one exists, would involve entering a world that makes the weirdness of quantum mechanics seem mundane, one where cause doesn t have to precede effect and information can be lost forever. Quantum mechanics itself might hold the doorway to this world, if only we could push hard enough to break through. To move beyond quantum mechanics, we must first look to its birth. At the turn of the 20th century, before the term quantum had even been coined, there was a widespread view among those in the know that physics was more or less complete. In 1900, the physicist Lord Kelvin proclaimed that physics was virtually complete, with only minor mysteries left to be solved. As it turned out, humble pie was on the menu. Within five years, quantum mechanics would appear on the scene, providing our most accurate description of things at the smallest scales. It brought with it a host of weird predictions that were impossible to reconcile with the classical picture. Knowing an object s position fundamentally prevented you learning about its momentum, for example. And particles separated by vast distances could be so intimately linked that it seemed as if information was passing between If you think our best theory of reality is weird now, stay tuned, says physicist Ciarán Lee BEYOND OUANTUM 28 NewScientist 16 June 2018

them faster than the speed of light even though no such information transfer occurs. So why had nobody seen this revolution coming? Well, most quantum effects are invisible in our daily lives: once you zoom out from particles to the human level, quantum mechanics reduces to classical physics. We had to wait until laboratory experiments gained sufficient control over nature to reveal its slippery quantum character. If quantum mechanics is itself due a revolution, any future theory would similarly need to reduce to quantum physics at laboratory scales. Our best hints that quantum mechanics might not be the full picture come, oddly enough, from the physics of the very large. BEN BLOOM/GETTY IMAGES To make sense of reality at the scale of galaxies, we need general relativity, a theory of gravity first laid out by Einstein in 1915. Although general relativity and quantum physics represent equally successful physical theories, the two are fundamentally incompatible. One glaring problem concerns black holes, entities whose gravitational attraction is so strong that not even light can escape their pull. If you throw a quantum particle into one, information about its properties simply disappears. This is deeply weird: ordinarily, any missing information in quantum mechanics can always be found by expanding your viewpoint. Think of it as a missing set of keys: they are never really missing, only being searched for in the wrong places. Information about the physical properties of a particle lost to a black hole, however, can t be found anywhere even if you include the whole universe in your search. This black hole information paradox has bothered many great physicists, including Stephen Hawking. The trouble doesn t end there. Take causality, the cherished notion that cause always precedes effect. You may think this principle applies at all times and places throughout the universe. Instead, general relativity grants every observer their own notion of present and future, so it allows different people to disagree about the causal ordering of certain events. In contrast, quantum mechanics says that events occur in a fixed causal order that different observers always agree on. To accommodate these conflicting ideas, whatever theory lies beyond quantum mechanics must allow for our notions of causality to get very funky indeed. Unpredicted weirdness Luckily for those of us pursuing such a theory, in the last decade or so researchers like Lucien Hardy at the Perimeter Institute for Theoretical Physics in Canada have been pushing the limits of quantum mechanics. By tweaking our standard notions, they have come up with a landscape of fresh theories that at first sight may not correspond to our physical reality, but do maintain some of the hallmarks of quantumness and allow a rigorous investigation of possible postquantum theories. My long-time collaborator John Selby at the Perimeter Institute and I used these to make an interesting discovery. To find a theory that reduces to quantum mechanics in the same way as quantum mechanics reduces to Quantum mechanics could hold the door to a new world if we push hard enough classical physics we proved you must either abandon the concept of causality, or the notion that information is conserved, or both. Although quantum mechanics is often regarded as weird, it had left untouched these two fundamental prejudices of ours about the natural world. Now it turns out that to find a better theory of reality, we need to look for the weirdness that quantum mechanics didn t predict at all. The clouds on the horizon of quantum physics could be the harbingers of its eventual replacement. Work done in the early 90s by Rafael Sorkin, a quantum gravity researcher now based at the Perimeter Institute, has helped us shed light on what such a replacement could look like. Sorkin considered one of the benchmark tests in quantum physics, the double-slit experiment, in which particles are fired one by one at a screen through a barrier with two slits. According to common sense, at the end of the experiment there should be only two slit-like marks on the screen, one for each opening the particles could have gone through. This doesn t happen: quantum interference causes a pattern to appear, as though the stream of particles was behaving like a barrage of waves. Sorkin calculated that when you add a third slit to the barrier, quantum mechanics would predict an interference pattern that looks like the patterns for each possible twoslit combination laid over one another. In other words, no new mysterious effects emerge in the three-slit case that aren t present in the two-slit one, although the reason for this is unclear. So far, experiments have put bounds on how big any hypothetical effects could be, but haven t been able to rule them out yet. Along with our collaborators, Selby and I have shown that any such effects must violate information conservation. In other words, they could be a hallmark of any future post-quantum theory. Of course, the jury is still out on the specific form such a theory would take. But one thing s for sure: if you think quantum mechanics is weird, you ain t seen nothing yet. Ciarán Lee (@quantumciaran) is a quantum researcher at University College London 16 June 2018 NewScientist 29

COVER STORY Life s true cradle Was it Darwin s warm little pond, an exotic crater lake or icy shores? Penny Sarchet joins the epic hunt for the place where it all began NEARLY 4 billion years ago, the first life appeared on our planet. It would have looked unlike any life as we know it today, more basic even than bacterial cells barely more than a few genetic molecules packaged up in some kind of a sac. Working out how this popped into existence is one of our greatest intellectual endeavours. And at the root of the problem is an epic hunt for the perfect location. Researchers studying the origins of life each have their favourite spot. Some sites offer the right molecular ingredients, others provide ready-made little containers to hold these early reactions. But is it possible that one special place had the perfect combination of all the conditions essential for the chemistry of life? And does a similar place still exist today, on Earth or elsewhere in the universe? Charles Darwin kicked off the quest. In a letter he wrote to the botanist Joseph Dalton Hooker in 1871, he described a hypothetical warm little pond, rich in chemicals and salts, with sources of light, heat and electricity. He imagined that in such an environment, proteins might spontaneously form, ready to turn into something more complex. In the TIM MCDONAGH 1950s, chemists Stanley Miller and Harold Urey managed to create Darwin s pond in the lab. They mixed water with gases they thought would have been present on early Earth, and zapped them with simulated lightning. This produced amino acids, the building blocks of all proteins. Basic supplies Their experiment is one of the most famous of the last century, but we now know that what they created, protein components in water, is not enough to constitute life. To truly get going, life would have needed three quite special features: a genetic code that would carry the blueprint for making cells, a chemical system or metabolism to generate the energy to power the cells, and a sac or membrane to hold it all together. In all organisms alive today, the trio is built from the same atoms: carbon, hydrogen, oxygen, nitrogen, phosphorus and sulphur. So at the most basic level, life s crucible must have offered a ready supply of these atoms and the right conditions for them to come together and form all three of life s essential features. While biochemists were pondering these matters, deep-sea explorers made a surprising discovery in the Pacific. In 1979, the US submersible Alvin was diving at a volcanic ridge 2 kilometres beneath the surface when it discovered black smokers, underwater vents spewing superheated water at 350 C. These were host to a whole ecosystem unlike any that had been seen before. The find was fortuitous: at a time when biologists were trying to imagine what life not-as-we-know-it might look like, here were living, thriving examples. There were some very alien, ancient-looking fauna living around [black > 16 June 2018 NewScientist 31

smokers], says Philipp Holliger at the MRC Laboratory of Molecular Biology in Cambridge, UK. Coincidentally, only two years later the Voyager 2 space probe was sparking interest in the possibility of extraterrestrial life and its origins by sending back photos of Jupiter s icy moon Europa (see Could space be the place?, page 34). People thought it would have a subsurface ocean with vents, says Holliger. Their speculation fuelled excitement that deep hydrothermal vents could have kickstarted life elsewhere as well as on Earth. That idea is still fixed in the public imagination, even though researchers have long since left it behind. There are relatively few people defending black smokers as the place that life started, says Nick Lane at University College London. The problem is that they are low in hydrogen and too hot for nascent molecules to stay intact for long. In particular, RNA a molecule that many evolutionary biologists think served as life s genetic material before DNA degrades rapidly at high temperatures. Then came the discovery, in 2000, of cooler submarine vents in the mid-atlantic. The site, There were some very alien fauna living in these locations christened the Lost City, was a collection of alkaline hydrothermal vents. Here, seawater reacts with the minerals of the sea floor to produce rocks that are riddled with tiny pores, as well as a warm fluid that is rich in hydrogen. Lane thinks the rocky pores would have been ideal for the reactions of early life. In particular, the electrochemical gradient between the alkaline vent fluid and the acidic seawater back then could have led to the spontaneous formation of acetyl phosphate and pyrophosphate, two molecules that act just like ATP, the chemical that powers living cells today. The rest of the essentials could have followed, says Lane. Acetyl phosphate and pryophosphate could have provided the energy to synthesise the first organic molecules from dissolved carbon dioxide and hydrogen gas. From these, the building blocks of proteins and RNA might have been made. If lipids had been made too, they may have coated the inside of the pores to form the first cell membranes. Alkaline ocean vents are great in the way they offer a ready-made metabolism to run life s first reactions, but they have a problem: SIX CANDIDATES FOR LIFE S CRUCIBLE Life could have got started in a range of environments, from the bottom of the oceans to deserts. Each has its pros and cons Alkaline ocean vent Around 65 C Large columns of rock on the sea floor, riddled with tiny pores, where alkaline water bubbles into the ocean Hot freshwater pool Around 90 C Small pools on warm volcanic land, repeatedly replenished by geysers or hot springs in between dry spells Geothermal field Around 150 C Hot, geothermally active rocky landscapes with cooler water vapour enriched with minerals WHERE ON EARTH TODAY Lost City in the mid-atlantic ARGUMENTS IN FAVOUR: Lots of hydrogen; a chemical set-up similar to modern metabolisms; geothermal energy to drive reactions ARGUMENTS AGAINST: Too salty for membranes; too wet for large biomolecules COURTESY OF UNIVERSITY OF WASHINGTON WHERE ON EARTH TODAY Bumpass Hell in California ARGUMENTS IN FAVOUR: Wet and dry cycles help large biomolecules form; membranes form naturally if fatty acids are present ARGUMENTS AGAINST: Unclear how metabolism could have got started PRISMA BY DUKAS PRESSEAGENTUR GMBH / ALAMY STOCK PHOTO WHERE ON EARTH TODAY Mutnovsky field in Kamchatka, Russia ARGUMENTS IN FAVOUR: Vapour rich in essential elements; water droplets could help RNA to form ARGUMENTS AGAINST: Unclear how metabolism could have got started ROBERTHARDING / ALAMY STOCK PHOTO 32 NewScientist 16 June 2018

they are too wet, says David Deamer at the University of California in Santa Cruz. Proteins, genetic material and lipids are polymers, chains made from their respective building blocks. Way back when things were just getting started and biomolecules were painfully rare, something had to stop the building blocks being too diluted unable to bump into each other and form chains. The answer, says Deamer, is a place with wet and dry cycles to bring things together: If you have cycles, you can have natural experiments going on again and again, thousands of times until something interesting happens. There s another argument in favour of life starting on land, in an environment that dried up periodically. Dehydration plays a key role in making organic molecules. Every time a building block is added to a growing chain, a molecule of water is released. Enzymes control the process in modern cells. Without enzymes to help, a dryer environment would have encouraged such reactions in life s early stages. Deamer imagines volcanic islands with freshwater pools that are sprayed by hot springs or geysers in between drying out. These pools would also have been good places to form the first fatty membranes much better than deep-sea vents. In the ocean, dissolved calcium and magnesium ions could have stopped the fatty acids coming together to make a continuous membrane. But in fresh water, lipids easily coalesce in the same way as oily drops clump together when you mix oil and water. Desert origins Deamer s team has been taking samples from hot springs in Yellowstone National Park and at Bumpass Hell in Mount Lassen National Park, California, and putting them through wet-dry cycles. In unpublished work, they have found that if they dry out these samples and then rehydrate them, RNA-like molecules can become encapsulated within fatty membranes, resembling genetic material within rudimentary proto-cells. In a slight twist to the hot pools scenario, Armen Mulkidjanian at Osnabrück University, Germany, prefers an even drier environment, in the form of geothermal fields hot rocks that release water vapour heated by geological activity inside Earth. His team argues that the chemistry here is similar to what goes on inside our own cells. Geothermal vapour is enriched in elements important for life, says Mulkidjanian. As the vapour condenses, some experiments suggest that the tiny droplets that form can create ideal conditions for components of RNA to materialise. However, to make RNA, you first need to make the sugar ribose the R in RNA. The atoms for that would probably have been available in the atmosphere, but tend to form something other than ribose unless given a helping hand. Borate minerals could have done the job, according to Steven Benner at the Foundation for Applied Molecular Evolution in Florida. They guide reactions towards producing more ribose. Better still, they stop the ribose from falling apart. Benner thinks this makes deserts an appealing candidate for life s cradle. The rocks there are rich in borates and occasional rains > Desert Around 80 C Arid land with sporadic rains that bring minerals and compounds from the mountains and atmosphere WHERE ON EARTH TODAY Death Valley, California Ice Around 0 C Frozen water riddled with narrow fissures and channels, filled with concentrated brine WHERE ON EARTH TODAY Freshwater at high altitudes or in cold climates Impact crater Around 2000 C (Upon meteorite impact, then much cooler) Iron-rich rocks heated by successive meteorite impacts WHERE ON EARTH TODAY Meteor Crater in Arizona ARGUMENTS IN FAVOUR: Borate from the rocks helps RNA components to form ARGUMENTS AGAINST: Unclear how metabolism could have got started LARRY GEDDIS / ALAMY STOCK PHOTO ARGUMENTS IN FAVOUR: Long strands of genetic material can assemble and build further strands in a nearly self-sustaining system ARGUMENTS AGAINST: Unclear how metabolism could have got started NATURFOTO-ONLINE / ALAMY STOCK PHOTO ARGUMENTS IN FAVOUR: Right conditions for genetic material, proteins and membranes to form ARGUMENTS AGAINST: Implies a cyanide-based metabolism, unlike anything on Earth today NATIONAL MAP 16 June 2018 NewScientist 33

would have leached them out. If you have been to Death Valley, you have seen an example of what we have in mind, he says. One thing all these environments have in common is heat. This makes sense, in that warmer temperatures can help power chemical reactions. So it comes as a bit of a surprise that some researchers think life could have begun on ice. When water freezes, everything dissolved in it gets dehydrated and concentrated into brine, says Holliger. The brines get trapped inside narrow cracks in the ice, where polymer chains can form, and the cool temperatures help stabilise biomolecules long enough for them to keep growing. Researchers have experimented with making long RNA strands by freezing a solution of its building blocks together with metal ions. These ions are common in the environment and help catalyse the reactions. Holliger and his colleagues have also found that repeated freeze-thaw cycles help build enzymes made of RNA. That s key because the enzymes can themselves make more RNA strands precisely the kind of set-up you might expect for early life. I think ice is an interesting medium to facilitate that important transition towards a system that can propagate itself, says Holliger. All these land and freshwater scenarios have a catch. Unlike Lane s alkaline vents, they don t offer an easy explanation for how metabolism evolved. And they all lack a convincing hypothesis for how all three pillars of early life genetic material, metabolism and membranes came together. Everyone pretty much agreed 50-odd years ago that you couldn t get everything in one go, COULD SPACE BE THE PLACE? Panspermia is the idea that life on planets such as Earth was seeded from space, but how likely is it? I think it shouldn t be ruled out, but it s not worth considering it until we ve more extensively explored likely possibilities on Earth, says John Sutherland at the MRC Laboratory of Molecular Biology in Cambridge, UK. If life arrived from elsewhere, it would have had to make it through the atmosphere without burning up, and then adapt to our planet. A more probable scenario is that some of the building blocks arrived by interstellar transport and were assembled after delivery. Some meteorites contain fatty molecules that can coalesce into membranes, an essential component of all cells (see main story). And the building blocks of proteins have been found around comets. Despite this, there is still some argument over whether these components could have arrived intact in large enough amounts. The chemistry of life may THE ONE THAT HAD IT ALL? Hypothetically, one place could have offered everything necessary for life to get started Terrestrial hydrothermal crater lake Around 165 C A hot lake within a meteorite crater possibly with ice around the edge WHERE ON EARTH TODAY Lonar crater, India ARGUMENTS IN FAVOUR: Conditions are right for three components of early life genetic material, proteins and membranes ARGUMENTS AGAINST: Implies a metabolism unlike anything on Earth today... although if an alkaline vent happened to be nearby then maybe just maybe this could have been the place that had it all have started independently on Earth and elsewhere in the universe, in which case the quest to pin down its origins at home could help us find it in the great beyond. For every possible cradle of life on Earth, there could be an equivalent in space. The Gale crater on Mars, which is being explored by NASA s Curiosity rover, used to have a lake, and there are signs of alkaline hydrothermal vents on Enceladus and Europa, icy moons of Saturn and Jupiter respectively. And that s just within our own solar system. DINODIA PHOTOS / ALAMY STOCK PHOTO says John Sutherland at the MRC Laboratory of Molecular Biology. Most researchers fall into one of two camps, depending on whether they focus on genetics or metabolism when looking for the origins of life. Sutherland s team is seeking a scenario that creates everything in one place, at one time. We deliberately set out to look for chemistry that would make [all] the various bits and pieces, he says. That led them to meteorite impacts, which would have been common 4 billion years ago. These rocks from outer space could have brought hydrogen cyanide with them, a convenient source of three of the essential elements of organic molecules: carbon, nitrogen and hydrogen. Sutherland s experiments show that if accumulations of hydrogen cyanide became superheated say by another meteor impact in the presence of water and UV light, they could have formed a whole suite of precursor molecules for RNA, proteins and lipids. There s a snag though: No It comes as a surprise that some think life could have begun on ice life uses cyanide as a source of either carbon or nitrogen, says Lane. So was life s cradle wet, dry or frozen? I don t think these are mutually exclusive, says Holliger. For example, Sutherland s meteor-impact chemistry needs at least one wet-dry cycle and hydrogen sulphide, both of which could have been provided by hydrothermal activity at hot freshwater pools, the kind of environment Deamer thinks is good for membranes. One place where all of this could have come together is a hydrothermal lake inside a meteorite crater. We know that when a big meteorite hits, it causes fissuring of the crust, says Sutherland. If water pools in the crater, it can percolate down through the cracks and go deep enough inside Earth to be heated and bubble up again. Hydrothermal crater lakes would have been abundant on the proto-continents of the young Earth, says Sankar Chatterjee at Texas Tech University. Why stop there? Throw in ice around the edge (like you see at Yellowstone in the winter) and a nearby terrestrial alkaline hydrothermal vent (similar to those at the bottom of the ocean but on land) and you might get Holliger s self-sustaining RNA enzymes, and Lane s ready-made metabolism. Everything you need wrapped up in one place. Penny Sarchet is deputy news editor at New Scientist 34 NewScientist 16 June 2018

Flavour of the month? Spices are causing a stir as cheap and easy cure-alls for everything from diabetes to dementia, but should we swallow the hype, asks Sandrine Ceurstemont TURMERIC and bread makes for an unusual breakfast. But when Mark Wahlqvist served it to a group of older people in Taiwan, he had high hopes. They had been diagnosed as heading for diabetes, which can affect mental abilities. Having heard that the spice could have cognitive benefits, he wanted to put it to the test. The idea that turmeric might be brain-protective is novel, says Wahlqvist, currently at the National Health Research Institutes in Taipei, Taiwan. To those following the latest food trends, however, the spice s brain-boosting potential is unlikely to raise an eyebrow. It is just one in a long list of turmeric s supposed benefits that have seen it proclaimed as a cheap and effective super food. As a result, what once may have been gathering dust in your spice rack is now the star attraction at trendy coffee shops selling golden lattes. > WESTEND61/GETTY 16 June 2018 NewScientist 35

DESIGN PICS/PLAINPICTURE LETHAL INGESTION The intense burning sensation you get when eating hot chilli peppers can feel all-consuming, but can consuming spices ever prove fatal? Potentially. In one rare case, a man who was eating ghost peppers one of the world s hottest varieties as part of a competition started being sick and complained of chest pain. It turned out that the force of vomiting had ruptured his oesophagus and he required surgery. Without medical attention he would probably have died. Nutmeg, which is sometimes used as a recreational drug, could be risky too. It contains myristicin, a volatile oil that can have hallucinatory and amphetamine-like effects when broken down in the body. One student looking for a cheap high ended up in hospital after blending 50 grams of the spice into a milkshake. Even such a high dose A nutmeg milkshake led to one student looking for a high ending up in hospital is unlikely to be fatal, but there are a few reported deaths from overdosing on the spice. And while there is little chance of you ingesting too much of a spice by accident I don t think anybody has to worry about eating too much curry, says Kathryn Nelson at the University of Minnesota spice supplements, which contain higher doses of active ingredients, can cause problems by interacting with medications. Curcumin, for example, is thought to thin blood and so should be avoided when taking anticoagulant medications. Supplements are often selfprescribed, and people may feel that because they are sold as natural remedies they are harmless. However, in most cases scientific research has yet to determine their benefits and side effects (see main story). Other spices are vying for popularity, too. From cinnamon to saffron, the internet is rife with claims about the healing powers of spices, suggesting that they can help with just about any condition from depression to cardiovascular disease and cancer. Even Hillary Clinton has reportedly jumped on the bandwagon. After reading that hot peppers can boost the immune system, she was eating 300% Increase in Google searches for turmeric between 2012 and 2016 GOOGLE TRENDS, US one a day during the 2016 US presidential election campaign in an attempt to improve her stamina. The question is whether we are swallowing anything more than a load of hype. The promise of the medicinal benefits of spices is rooted in traditional medicine. In holistic Ayurvedic medicine, which has been practised for more than 3000 years in what is now India, turmeric is mixed with milk as a remedy for colds or made into a paste that is applied as a topical treatment for sprains or inflamed joints. More than 300 herbs and spices are used in Chinese medicine, where cinnamon is the go-to option for those wanting relief from muscle pain, as well as being recommended to control excessive sweating, among other ailments. Spices may be added to food or steeped in liquid as a medicinal drink, often in combination. The allure of these therapeutic properties spread as herbs and spices were introduces to Europe from Asia and Africa in the Middle Ages, and has blossomed as more immigrants settled in Europe in the 20th century, says Wahlqvist. But in the past few years, as our appetite has grown for functional foods those with health benefits beyond their nutritional value spices have reached cult status. In Europe, imports of spices and herbs have increased by 6.1 per cent annually between 2012 and 2016. Google searches for turmeric shot up 300 per cent in the US over this period. And sales of supplements of curcumin, an active ingredient in turmeric, reportedly raked in over $20 million in 2014. Scientists, too, have started to wake up to the idea that there could be something in it. If relatively inexpensive components of the diet were to mitigate the effects of diabetes and 36 NewScientist 16 June 2018

In Ayurvedic medicine, which has been practised for millennia in India, turmeric is used as a remedy for colds, as well as sprained and inflamed joints DARIO SARTINI/ FLICKR EDITORIAL/GETTY IMAGES dementia, for example, that would be a welcome advance, says Wahlqvist. The number of studies about herbs and spices has risen dramatically in the past decade, and each week around 50 new scientific papers are published on the biological interactions of curcumin alone. Yet despite this rapid accumulation of data, the findings are pretty confusing. In perhaps the largest study to date, Liming Li at Peking University in Beijing, China, and his colleagues followed 480,000 apparently healthy adults in China for about seven years. They found that those who ate chilli peppers almost every day were 14 per cent less likely to die in that time than those who consumed them less than once a week (see Hot tip, page 38). If the effects are real, what is it about spices that makes them so healthy? Many of the claims are based on the idea that they contain powerful antioxidants. As our bodies break down the food we eat, they produce rogue molecules called free radicals that contribute to ageing and disease. Antioxidants are often thought to be able to mop these up. Spices are rich in polyphenols, a group of plant compounds thought to have antioxidant properties. This is what first piqued the curiosity of Elizabeth Opara at Kingston University in the UK. It seems that when you categorise different foods based on antioxidant capacity, herbs and spices are right at the top, she says. Opara and her team were keen to figure out whether different cooking techniques affected this antioxidant activity. In lab tests, they looked at herbs and spices, including cinnamon, cloves, parsley, sage and thyme. They found that microwaving, simmering and stewing, which all involve heating a liquid, increased antioxidant action, whereas grilling and frying, which use dry heat, decreased it. But don t reach for your golden latte just yet. Later research found that consuming herbs and spices led to no increase in antioxidant activity in people s blood. Work now suggests that if polyphenols have any benefits at all, they aren t linked to the ability $20m worth of curcumin supplements were sold in the US in 2014 SOURCE: JOURNAL OF MEDICINAL CHEMISTRY, VOL 60, P 1620 to curb antioxidants, says Opara. This highlights one big problem with much of the research on spices: it is often done in the lab, and what looks promising in a cell sample rarely bears out in the human body. Other studies in people look more promising, though. For their breakfast experiment, Wahlqvist and his colleagues wanted to see whether the quantities of turmeric and cinnamon typically eaten in food might help with memory impairment that develops with prediabetes. Some work suggests that cinnamon can lower insulin resistance, which could help control blood sugar levels and guard against the associated neurodegeneration. In their study, a group of 48 people with prediabetes received one of four breakfasts: 1 gram of turmeric, 2 grams of cinnamon, both spices or a placebo, along with a serving of white bread a nutritionally inert filler that would allow the researchers to isolate the potential effect of the spices. Those who ate the turmeric breakfast had improvements to their working memory 6 hours later. Tests of this kind of memory are used to predict cognitive decline. There were no memory changes in the other groups. Just because there seems to be a relationship between the spice and memory doesn t > 16 June 2018 NewScientist 37

HOT TIP mean that it is causing the change, however: other factors that weren t controlled for could be at play. And the study only included people who eat a Chinese diet, which could affect results. What s more, the team doesn t know whether changes are long-lasting or how turmeric could be having an effect. Perhaps chemical compounds in turmeric can provide clues. Assessing the effect of spices as food can be complicated by the fact they are consumed in small quantities as part of a much wider diet. So Gary Small at the University of California, Los Angeles, and his colleagues homed in on the powers of G.M.B. AKASH/PANOS 50 new manuscripts are published about curcumin each week SOURCE: JOURNAL OF MEDICINAL CHEMISTRY VOL 60, P 1620 The active ingredient in hot chilli peppers is the heat-producing compound capsaicin, which is thought to help the plant deter herbivores from eating it. Those brave enough to ingest it could find their fat melting away as a result. Masayuki Saito at Tenshi College in Japan and his colleagues have been looking at how capsaicin can activate brown fat. Whereas the more common white fat stores energy from food, brown fat turns food straight into body heat. Research suggests that cold triggers brown fat to convert more of the food to heat, resulting in weight loss. Capsaicin seems to mimic this effect. In a trial, Saito s team found that the brown fat in healthy young men given 1.5 milligrams of capsaicin became activated, burning more energy than a group given a placebo. You don t have to eat chillies to reap other benefits from capsaicin, however. In a study of more than Chilli peppers could be a cheap alternative to local anaesthetics 550 adults experiencing numbness and burning pain due to nerve problems, Maija Haanpää at the Helsinki University Central Hospital in Finland and her colleagues found that a skin patch containing capsaicin applied to the affected area could provide as effective pain relief as an oral medication but faster and with fewer side effects. If you grow chilli peppers hot enough, their numbing power could even be used as an anaesthetic. Last year, the hottest pepper ever was grown in the UK, coming in at 2.48 million units on the Scoville scale; the previous record was 1.6 million. Now, researchers at Nottingham Trent University in the UK want to see if they can extract the oil from the chilli and use it to numb the skin. This could be especially useful as a cheaper alternative to existing local anaesthetics in developing countries. curcumin supplements. Making up about 3 per cent of turmeric, curcumin has become a buzzword in itself and is widely sold as a dietary supplement. More than 120 clinical trials have tested its effectiveness against numerous conditions, from Alzheimer s disease to erectile dysfunction. In a study published earlier this year, Small s team looked at its long-term effect on cognitive abilities in people middle-aged and older with mild, age-related memory issues. One group of 40 took a pill containing 90 milligrams of curcumin twice a day. Another group received a placebo. Both were given cognitive tests every six months over 18 months and some people received brain scans. The team found that the memory and mental focus of those taking curcumin improved significantly, while there was no difference for the others. The amount of plaques and tangles of proteins thought to be a cause of cognitive impairment in brain regions that modulate mood and memory also fell. I was pleasantly surprised that it worked in a relatively small sample, says Small. He suspects that curcumin could be provoking an anti-inflammatory response. Inflammation is the body s response to injury or infection, but modern living can make it go awry by constantly triggering the process. This has been implicated in conditions ranging from heart disease to depression. Reducing inflammation in the brain to 38 NewScientist 16 June 2018

DANIEL ACKER/BLOOMBERG VIA GETTY IMAGES Turmeric root contains curcumin, which may improve memory and mental focus dampen down swelling could allow neural cells to function better. This may be connected to the reduction in tangles Small s team observed. If so, he thinks curcumin pills could be an alternative for people who struggle to make lifestyle changes, such as improving their diet or exercising more. It s hard for people to change their behaviour, says Small. Here we re just asking people to take some capsules a couple of times a day. He and his team now plan to follow up with a larger study to confirm the effect. They also found a modest mood boost in the group given the curcumin, something they would like to probe further by including participants with mild depression. In some cases, plaques and tangles have been observed in people who have low mood but not dementia. We would like to understand that more, says Small. Not everyone is convinced about curcumin, however. Last year, Kathryn Nelson at the University of Minnesota and her colleagues, who validate new chemicals that could be developed into drugs, published a scathing review of curcumin s supposed health benefits. Curcumin research may have entered the steep section of the hyperbolic black hole of natural products where effort rapidly exceeds utility, they wrote. One of the biggest criticisms is what they call the dark side of the spice: it seems to have an effect in so many studies, which may be due to false positives. If a chemical is STUART FREEDMAN/PANOS active in every test, that s a red flag, says Nelson. It means that it might not really be active in any of them. When hunting for drug candidates, preliminary lab experiments look at whether a chemical is able to bind to a protein implicated in a disease. But some chemicals can give false signals. Curcumin is one of them. For instance, it can disrupt cell membranes, making it Hillary Clinton reportedly ate a chilli a day to improve her stamina while campaigning seem like it is interacting with proteins on a cell s surface. In various solutions, it also seems to fluoresce, which is often sought out as a marker of activity. Curcumin has appeared to have an effect in drug screening for many conditions, yet it has never led to a proven treatment. There are even questions about whether enough of the stuff is absorbed into the body to do anything. Even when you give people up to 12 grams a day of curcumin, you can t find it in their bloodstream, says Nelson. Retracted evidence Human error plays a part, too. Several papers by Bharat Aggarwal, formerly at the University of Texas, laid the groundwork for clinical trials looking at the effect of curcumin on cancer, but were later retracted. As for cinnamon, a review of randomised trials of its effects on diabetes had to discard most identified studies because of the risk of bias. From the scant studies remaining, it concluded there was no strong evidence of any health effects. That doesn t mean spices are a lost cause but a lot more evidence is needed before we should take them seriously. And there may be beneficial effects we simply haven t discovered yet. Take the case of artemisinin, currently the most effective malaria treatment. The Nobel prize-winning discovery was made by screening 2000 remedies from Chinese medicine. Topical uses of spices should have more scope since active ingredients don t need to be absorbed into the bloodstream to work. Several teams are looking at the potential antimicrobial properties of spices, and even incorporating them into packaging to preserve food. People are using curcumin as a supplement and that s not what traditional medicine was doing to start with, says Nelson. Besides, there are other good reasons to fall in love with the contents of your spice rack. While they might not live up to their reputation as a cheap and easy panacea, spices have now been added to national dietary guidelines in both the US and Australia that previously focused on staples such as meat, carbohydrates, fruit and vegetables. Why? Adding spices to food is an easy way to cut down on salt, which can raise blood pressure. A diverse diet is widely recommended as the healthiest way to eat and variety, after all, is the spice of life. Sandrine Ceurstemont is a writer based in Morocco 16 June 2018 NewScientist 39

ATHENA PICTURES/GETTY IMAGES The video-assisted ref s a Will replay reviews make football refereeing decisions any better, asks Bob Holmes YOU win some, you lose some. Unless you re England then you just lose. As the 2018 World Cup kicks off in Russia, football fans across the globe are eagerly sizing up their team s chances. Will it be Germany again? Or dark horse Belgium? Or will the trophy go outside Europe for the first time since 2002? This year, fans will have someone new to blame when things go wrong: the video referee. For the first time in the World Cup, decisions in all 64 games of the tournament will be subject to review by a team of off-pitch officials watching video footage of the game. Referees are only human, and over the past decade or so we have learned how psychological tics can make decisions go awry. The aim of the new technology is to cut out these quirks of perception. Trouble is, it might end up just introducing new ones. We love to criticise, but it is hardly surprising that footballing officials make mistakes. They have to follow a fast-moving, free-flowing game and they can t watch all 22 players at once. But specific effects make some decisions more error-prone than others. Take offside decisions, the bugbear of many a football fan. An attacking player is offside if they are closer to the opposition s goal line than the second-last opponent at the time a 40 NewScientist 16 June 2018

teammate plays the ball towards them. This sounds simple enough (maybe), but it runs afoul of a visual illusion called the flash-lag effect: a moving object is perceived as being further forward than it actually is when a second event, in this case the pass, occurs. The brain is not so good at the exact timing of events because we don t need that at the conscious level, says Johan Wagemans, an experimental psychologist at the Catholic University of Leuven (KUL) in Belgium. This means that assistant referees, who observe play from the sidelines and help in judging offside decisions, often see players as offside when they actually aren t. In the 2002 World Cup in Japan, one out of four offside decisions was incorrect because of the flashlag, says Werner Helsen, a sports scientist also at KUL who heads referee training for UEFA, the European football association. You can t get rid of that with practice alone, says Wagemans. It s only something you can overcome by not trusting your perception any more, and correcting at the conscious level. Not accurate, but fair After the 2002 World Cup, football governing bodies began to give assistant referees video training to make them aware of the flash-lag effect. An independent analysis by Wagemans, Helsen and others showed that the number of offside errors fell by half between the 2002 and 2006 World Cups. Video-assisted refereeing, which is already in use in several competitions around the world, aims to improve the quality of referees decisions still further, by allowing off-pitch officials to review replays during the flow of the game. This will be used to verify calls at certain crucial moments: in the run-up to goals, in the event of a penalty kick or red card being awarded for a foul, and to ensure the right player is given a red or yellow card. In a study conducted for the International Football Association Board, which regulates the rules of football, Helsen found that such reviews prevent game-changing errors in about 9 per cent of matches. The overall accuracy of refereeing decisions rose from 93 per cent to 98.8 per cent. For positional judgements such as whether a foul occurred inside the penalty area, viewing a slow-motion replay helps an official get a call right, says Helsen. But other calls hinge on a player s intent, such as whether a foul was egregious enough to warrant a red card, or whether a player intended to touch the ball with their hand. Not every instance of Watching fouls in slow motion makes them look more intentional (left), one reason why video-assisted replays (right) need to be used with care that is as obvious as Argentinian legend Diego Maradona s unforgotten and unforgiven Hand of God goal, which helped knock England out of the 1986 World Cup. Here slow-motion video review might make decisions worse, not better again, because of the way our minds work. Slow motion changes the way we perceive incidents, says Henning Plessner, a psychologist at the University of Heidelberg in Germany. It looks as if the player has more time to decide what he does, so it always looks worse. With this perceptual bias in mind, video officials are instructed on when to use slow motion and when to use real time in replays. To check if a foul is inside or outside the penalty area, slow motion can be used, says Helsen. But to examine the impact of a foul or a tackle, real time has to be used. Over the years, psychologists have also identified a host of external factors affecting officials decisions, at least in lab-based tests. Hearing crowd noise seems to increase the likelihood of fouls being called in favour of the home team. Players shouts and cries of pain influence the decision of whether to give a yellow or red card for a foul tackle. This isn t conscious, and it s not going to happen if you have a very obvious foul, says Clare MacMahon, a cognitive sports scientist at Swinburne University in Melbourne, Australia. It s when the call could go either way, a borderline call, that these factors have an effect. Video-assisted refereeing should reduce such subjective influences. But others worry that paying too much attention to whether decisions are technically correct risks interfering with the subtle art of refereeing. There is an important law, which is not written in the book, says Helsen. The law of common sense. How this plays out shows most clearly in the awarding of penalty kicks. Penalties are the most severe call a referee can make, because most result in a goal. Back in 2001, Plessner showed that referees award two penalty kicks against the same team less often than they should if the calls were Football is a flawed game officiated over by flawed officials and that s why we love it independent events, apparently balancing their calls to avoid determining the outcome of the game. Everybody knows that if there are four or five penalties in a game, there s something wrong with the referee, he says. A referee has to guide a game. It should be fair, it should be balanced, and that s a different goal from just being accurate. Fan and football podcaster Chris Nee goes even further: football is a flawed game, he says, played and officiated over by flawed people. That is precisely why we love it so much and why, in his opinion, video-assisted referees are a waste of space. This is football s latest attempt at perfection it doesn t need, shouldn t want and can never achieve. It seems whether to employ video-assisted referees is itself a judgement call. Only one thing s for sure: whoever s in charge, England won t win. Bob Holmes is a New Scientist consultant based in Edmonton, Canada KIERAN GALVIN/NURPHOTO VIA GETTY IMAGES 16 June 2018 NewScientist 41

CULTURE These violent delights As Westworld s robots go off-script, Emily Wilson is hooked Westworld, Series 2, HBO, to 24 June IF YOU have yet to catch Westworld (fast approaching the end of season 2), here s why everyone from your friends to serious philosophers have been raving about it, or even writing long, serious essays on the issues that it raises. Westworld is set in a near future where, for a price, you can visit a super-realistic Wild West theme park in which the hosts are played by convincingly humanoid robots. As in the 1973 film on which the show is based, the robots are flesh on the outside, but machine inside. Westworld s visuals are stunning, and the tone set to deadly earnest. Inside the park, you can do what you like to the hosts, even if what you like is committing rape and murder. When the guests leave, the saloon gets cleaned, the robots are stitched up and have their memories wiped and it all begins again. Reset. Philosophers and psychologists are still wrestling with the morality of Westworld. If the robots are only programmed to feel pain, if it s not real pain, is it wrong to hurt them? Would you hurt them? Would people you know hurt them? We need answers to these questions and soon when out in the real world, robots already look halfconvincing and can hold pretty good conversations. And then there are the tough problems of consciousness and self-determination. Again, this is a big deal when, thanks to the billions being spent globally on brain research projects, scientists are working to understand human consciousness and the nature of such things as free will. Westworld circles and recircles these questions. It is a brutal show at times a line from Romeo and Juliet keeps being repeated in the first season: These violent delights have violent ends. At other times, though, it is slow and meditative as we close in on the nature of these robots. They think they are real, but we know they have been programmed by humans, that their memories are frequently false and almost always patchy, and that everything they say is from a script. It is a flexible, adaptive one, but still a script. We hear them repeat the same words over and over as each new group of guests arrive. Yet the robots seem conscious, even if their memories are being Two of the robot hosts, Dolores and her beloved Teddy messed with, and they have at least the illusion of free will. Robert Ford, co-creator of the theme park (played by Anthony Hopkins), references the bicameral mind, a theory of consciousness advanced in the 1970s by psychologist Julian Are the robots truly human a new species of us now they are writing their own story? Jaynes, when he explains how he achieved these states of mind in the robots. They are programmed to hear guiding voices in their heads, voices that they might eventually believe to be their own. Sure enough, as the show evolves, so do the robots. Some of them have been in the park a long time now. How many times has Dolores, the rancher s daughter (played by Evan Rachel Wood, and pictured below), been attacked and killed, and then put back together? The robots start to remember that this isn t their first time around the block. They wake from their dream. They go offscript. Are they truly human a new species of us now they are writing their own story? This is Westworld, though, where nothing is simple. In fact, it is frequently beyond baffling, chopping up timelines like there s no tomorrow, or maybe no yesterday. It is possible the robots have merely been programmed to wake up. Maybe their new lines were written for them, just like the old ones were. Maybe their new-found free will is nothing of the sort. But it is also possible that the same goes for all humans, even the old-fashioned, all-flesh kind. Somewhere in this dazzlingly difficult puzzle lies the genius of Westworld. HBO 42 NewScientist 16 June 2018

For more books and arts coverage, visit newscientist.com/culture THIS WEEK New expectations Discover a very different Charles Dickens, says Simon Ings Charles Dickens: Man of Science, Charles Dickens Museum, London, to 11 November EVEN as he became the most celebrated and prolific author, the most energetic editor and the most influential political and social campaigner of his day, Charles Dickens was well aware of the science around him. Indeed, he took inspiration from it, and was even engaged in promoting and explaining it. The trouble is, in an effort to build a show around this notion, the Charles Dickens Museum has fixated almost entirely on its hero s friendships. Because Dickens knew everybody, the show struggles to find its focus. Even with a following wind, it is hard to feel much excitement on learning that Ada Lovelace had Dickens read her a passage from Dombey and Son on her deathbed. But several other personal connections reflected in an impressive display of books, autographs and prints carry more weight. Dickens was also pals with Jane Marcet, author of the monstrously successful (and in the US, even more monstrously plagiarised) Conversations on Chemistry. A book mostly about Humphry Davy s work, Conversations may be considered the first popular science book never mind the first written by a woman. It inspired Michael Faraday to take up work that eventually led to his Christmas lectures, entitled The Chemical History of a Candle, which Dickens promptly Ada Lovelace had Dickens read her a passage from Dombey and Son on her deathbed serialised as short stories in his magazine Household Words. This publication, founded in 1850, and its successor All the Year Round are the real stars of the show. Aimed at a general audience, each issue had a blend of fiction, social campaigning and science. As such, they reflected their editor s growing interest in, and knowledge of, the new fields of energy and thermodynamics, OLI SCARFF/GETTY IMAGES Doughty Street, London: home to Dickens s scientific essays inspiring his writing on both fields and on chemistry. Other investigations of energy were less orthodox, like Dickens s discussion of the medical cures that might be obtained from mesmeric fluids. And it drove Dickens s friend George Henry Lewes spare that the man responsible for serious scientific essays in Household Words was the same man who let characters in his novels burst spontaneously into flame, as with the illiterate rag-and-bone man Krook (who holds the key to the legal battle at the heart of Bleak House). Writing about that notorious spontaneous human combustion scene, Lewes accused Dickens of cheap sensationalism and of giving currency to a vulgar error, perpetuating it in spite of the labours of a thousand philosophers. But he was on a losing wicket: contemporaries Mark Twain, Herman Melville and Washington Irving all had characters incandesce. It is not accuracy we expect of Dickens, though, it is vision. It may be interesting that Our Mutual Friend uses the word energy in its new scientific sense. But what really thrills the heart is to follow Krook s visitors up the stairs as they are about to find his body. See here, on my arm! See again, on the table here! Confound the stuff, it won t blow off smears like black fat! A thick, yellow liquor defiles them A stagnant, sickening oil with some natural repulsion in it that makes them both shudder Come and be horrified. Read this Sleep researcher Alice Gregory takes a lifelong look at our slumbers in Nodding Off: The science of sleep from cradle to grave (Bloomsbury). Visit this From Stephenson s Rocket to robots, the Great Exhibition of the North (from 22 June to 9 September, pictured at bottom) transforms Newcastle and Gateshead, celebrating the region s cultural achievements. Listen to this As part of BBC Radio 3 s Into the Forest season, the Breakfast show (18 to 22 June, 6.30-9 am) broadcasts live from five UK forests, exploring the myths, fairy tales, enchantment, escape and magical danger related to the forest in summer. AND MORE Crazy/Genius from The Atlantic with Derek Thompson. Provocative podcast on the perils of tech. Last chance Hurry on down to the Royal Albert Hall in London for the last section of its first Festival of Science, which ends on 10 July. Catch Star Men, a film about the poignant astronomy road trip of four retired pros, plus rock legend Rick Wakeman in the flesh talking about his passion for space. 16 June 2018 NewScientist 43

CULTURE Open your mind Negotiating a new era of psychedelics takes a great guide, says Helen Thomson How to Change Your Mind: The new science of psychedelics by Michael Pollan, Allen Lane MICHAEL POLLAN was born a little too late to ride the first wave of psychedelics. The only way I was going to get to Woodstock was if my parents drove me, he says in How To Change Your Mind. Fast-forward some decades and we join Pollan in his 50s, busy giving birth to himself. He has just smoked one of the world s most potent psychotropic drugs, the venom of the Sonoran desert toad. I felt something squeeze out from between my legs, but easily without struggle or pain. It was a boy: the infant me. That seemed exactly right: having died, I was now being reborn. This isn t just an account of a middle-aged man s foray into the underworld. In the 1950s, drugs like LSD and psilocybin found their way into psychotherapy. Viewed as little miracles, they were used to treat a variety of disorders, including alcoholism, anxiety and depression. Yet their disruptive effect on society bad trips, psychotic episodes, suicide meant exuberance gave way to moral panic. The establishment turned sharply against them. Pollan s book is the story of their renaissance, a fusion of history, philosophy and of science past, present and future. They are united through his personal quest for a spiritually significant experience, something Psychedelics might help answer big questions about consciousness that could change his mind in enduring ways. To become more open when the grooves of mental habit have been etched so deep as to seem inescapable was an appealing prospect, he says. The dangers of such a quest particularly with a minor heart problem are not lost on Pollan, who is an even-keeled sceptic (a professor of journalism). Thankfully, curiosity gets the better of fear. For under the mist of LSD, even a toilet trip is amazing: The arc of water I sent forth was truly the most beautiful thing I had ever seen, a waterfall of diamonds cascading into a pool, breaking its surface into a billion clattering fractals of light. A book that focuses so much on the mystical experiences of the mind on drugs is in danger of becoming boring, much like reading about another person s I turned into a sheaf of little papers, no bigger than Post-its, being scattered to the wind TED STRESHINSKY/CORBIS VIA GETTY IMAGES dreams. But Pollan navigates these waters carefully, drawing us onto firmer ground with accessible philosophy and neuroscience. For example, he sets out to show how combining neuroscientific technology with LSD and psilocybin is opening a window onto consciousness that may enable us to understand brain-mind links. This claim is a little grandiose, perhaps, but his take is certainly intriguing. New research shows how psychedelics introduce noise into the brain how they make it link disparate concepts, shaking us up to produce more unconventional ideas. Whether this will help answer the big questions of consciousness is hard to say, but it seems to be leading us down useful therapeutic avenues: Pollan recounts heart-warming stories of people helped through depression, cancer and addiction. This scientific backbone gives us distance when we need it. Take this episode: I turned into a sheaf of little papers, no bigger than Postits being scattered to the wind. But the I taking in this seeming catastrophe had no desire to chase after the slips and pile my old self back together. It is compelling, but we are still able to question whether this is a drug-induced hallucination or a path into a normally inaccessible part of our mental landscape. All of which lends itself to a joyful and educational romp around the unexplored side of our minds and how we need to change our brains to truly experience it. Helen Thomson is the author of Unthinkable: An extraordinary journey through the world s strangest brains, John Murray 44 NewScientist 16 June 2018

THE UNIVERSAL UNITS OF THE MIND HOW A SIMPLE DATA MODULE UNDERLIES ALL OUR THOUGHTS AND PERCEPTIONS SUMMER READING One of the foremost physicists of mid-victorian Britain, John Tyndall s contribution to science underpin our understanding of climate change, the atmosphere, and glaciology. He was also a pioneering mountaineer, friend to the political and literary elite of his day, and one of the great popular science communicators of his time. Roland Jackson s biography makes perfect summer reading. MICHAEL JESSOP AND TERRY HILL Available online and in bookshops 9780198788959 576 pages 25 16 June 2018 NewScientist 45

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LETTERS letters@newscientist.com @newscientist newscientist EDITOR S PICK The blazing sun can solve water shortages From Graham Hagens, Hamilton, Ontario, Canada Olive Heffernan says the idea of towing icebergs to Cape Town in South Africa is dubious and the city must consider alternatives to meet its future water requirements, including possible desalination of seawater (19 May, p 20). In fact, Cape Town is actively involved in a number of desalination projects, with the focus on reverse osmosis. This technology has two problems: it produces concentrated brine that must be disposed of, and it uses lots of energy. The long-term investment of building pipes far out into the ocean can solve the disposal problem. The cost of fossil or nuclear fuels is more significant. It can be argued, however, that Cape Town, and other coastal communities prone to drought, could benefit from an electrical grid supported by solar power. Unlike some other applications of solar energy, the production of potable water requires no battery storage to cope with periods of darkness, since excess water can be stored in tanks or reservoirs for use at night. Nor would sunless, rainy days be a problem. How not to catch cancer from medical software From C. Wright, Clarkson, Western Australia The recent article about hospital software bugs (19 May, p 34) caught my eye because I have received no response to a complaint about a related problem. This resulted in a false diagnosis of a rare cancer being entered into my records, possibly twice, at two major public medical centres in Australia. The first I knew about this was when a family doctor asked during an unrelated consultation, with a quizzical look, whether I had cancer. The name of the cancer incorrectly entered into my records was similar to that of an extremely rare but quite mild disease that I had been correctly diagnosed with in the 1990s. Both were named after the same doctor, who discovered them, as were a few other diseases. As I recall, my correct diagnosis was absent from my records. I assumed that the clinic s software hadn t recognised my diagnosis when someone tried to enter it and had defaulted to the name of the cancer instead. I was even more shocked years later when a letter from a specialist at a hospital listed the cancer but not my correct diagnosis as one of my existing conditions. I don t know whether the error occurred independently. When I explained the problem to one doctor, his response was to delete my correct diagnosis from my medical records. A false diagnosis taking the place of a correct one on a patient s medical records has many potential negative consequences, especially when a serious disease is confused with IGNITE YOUR CURIOSITY TRY SOMETHING NEW MEET THE SCIENTISTS THE ROYAL SOCIETY SUMMER SCIENCE FREE EVENT EXHIBITION 2 8 JULY 2018 Explore the science shaping our future, with the people making it happen. royalsociety.org/summer theroyalsociety @royalsociety #summerscience 52 NewScientist 16 June 2018

Can we bring it back please because it s been missing for a long, long time? Helen Mahoney responds to a report that the gene that led to the boom in human intelligence has been found (9 June, p 6) a mild one. I hope someone in the world of medical IT will take this issue seriously and fix it. I also hope all patients with rare diagnoses are warned to check their medical records. From Craig Graham, Lancaster, UK I was interested to read about user error and electronic systems in medicine. But I was disappointed there was so little mention of the progress made in this field. Since 1993, European standard 60601 and associated texts and updates have attempted to introduce a rigorous engineering approach to making sure that medical equipment does its job and is intuitive and easy to use. Manufacturers have to assess the ways in which mistakes can be made and, as far as is possible, design them out. The use of precautionary sticky notes in hospitals should be a thing of the past if policies mandate the use of equipment complying to this standard. I do not know how widespread such policies are, but highlighting the existence of the standard should help with their adoption. How would this placenta panacea work, then? From Y. W. Loke, Cambridge, UK Catherine de Lange describes the ambitions of Bob Hariri and Peter Diamandis to use stem cells from placentas to extend life (26 May, p 42). Having studied the placenta, I have a few questions for them. Where are stem cells located in the placenta? How do we distinguish them from the other types of placental cells? How can these stem cells be isolated from the placenta for clinical use? An endless battle of faker against detector From Paul Whiteley, Bittaford, Devon, UK Chris Baraniuk says that a machine learning system can now examine photos and detect fakes (26 May, p 10). It shouldn t be too long, then, before someone invents an algorithm that trains itself to repeatedly tweak a false image to avoid detection by the algorithm that spots fakes. You can tell what I write about from my name From Brian Horton, West Launceston, Tasmania, Australia It is not surprising that our names affect how other people view our age and personality (26 May, p 9). You can guess the approximate age of many people from their name, since fashions come and go. Our personality is mainly derived from our genes and our early environment both usually provided by the people who gave us our name. But then, if your name doesn t suit your personality, you can do what half my family members have done: use a variant of the correct name or change it to something completely different. Smart meters as a plan for peak power pricing From Nick Hunn, London, UK N. C. Friswell wonders whether the peak pricing on smart meters has gone away (Letters, 26 May). He is right to be suspicious: it hasn t. The specification for the smart meters being rolled out in the UK contains the most complex pricing capabilities of any in the world. For example, it allows energy suppliers to divide the > ARTS & IDEAS WITH SCIENCE MUSEUM, BRITISH FILM INSTITUTE, ROUNDHOUSE, SUNDAY PAPERS LIVE & REFINERY29 FUN & FITNESS WITH MASS YOGA, DANCE WORKSHOPS & SUNDAY SPORTS DAY 16 June 2018 NewScientist 53

LETTERS letters@newscientist.com @newscientist newscientist day into eight blocks, which can be any multiple of 30 minutes. Within each block, there can be four tiers of pricing, so that the cost of energy can change depending on how much you use within each period. The charging pattern can be different for every customer. This dates back to the days when some companies mis-sold energy plans on the doorstep. Some advocated customising tariffs for individual customers to persuade them to switch supplier. Such complex tariffs were banned, but the capability to remotely program meters to operate them remains. The UK government insists on it in every gas and electricity meter. Eco-labelling done right and independently From Francesca Lipscombe, The New Zealand Ecolabelling Trust, Auckland Thank you for Fred Pearce s comment on eco-labelling (12 May, p 22). Many of us share the concern about greenwash. Fortunately, there is a simple TOM GAULD answer for consumers worldwide. Type 1 ecolabels all operate using independently established standards created for the goods or service in question. Individual standards are scientifically robust and transparent, and cover the product or service under scrutiny from cradle to grave. The licensees are independently audited against the standards and all who issue licences subscribe to the Global Ecolabelling Network whose members around the world will be pleased to offer support to UK companies in implementing such a scheme. We have more doubts on genetic modification From Richard Mellish, London, UK Michael Le Page says there is no reliable evidence that any existing GM food is less safe than conventional food (26 May, p 28). If I were anti-gm, I would regard those as weasel words: in the hallowed phrase, absence of evidence is not evidence of absence. More to the point is whether there is any reason to suppose that any of these GM foods might be less safe and how that stacks up against the arguments in their favour. From Merlin Reader, London, UK Le Page says virtually every GM crop on the market is designed to help the farmer who grows it. If it is publicly funded this may be true. But the first legal duty of private companies is to maximise shareholder profit. So they generate patents and terminator genes that force farmers to buy new seed every year, and design pesticide resistance rather than disease resistance into many products. Mixed recipes for saving the environment From Neil Doherty, Barnsley, South Yorkshire, UK I frequently find myself wrestling with my conscience about my meat eating (5 May, p 30). I am concerned about the increasing numbers of people doing it and the environmental costs, and see animal treatment as a separate issue. Producers seem to try to serve vegans, vegetarians or meat eaters. I find a more amenable solution in cooking my chilli recipe with a mix of vegetarian meat substitute and real meat. It still has the taste and texture of meat but with less of an environmental impact. From Emma Hardesty, Vail, Arizona, US Niall Firth overlooked a crucial factor in favour of non-meat meats. Some people simply like their taste, texture, aromas, convenience and earth-friendly aspects for themselves not to satisfy a craving for the real thing. Plastic pollution s past and present prevalence From Colin Reynolds, Marple, Cheshire, UK Aisling Irwin reports the ubiquity of plastic pollution (19 May, p 25). This reminds me of a visit to my school in the mid-1960s bya photographer following an Antarctic expedition. They claimed that, even then, every sample of Antarctic seawater contained microscopic fragments of nylon from fishing nets. Presumably now so do we. For the record Cyril Burt was involved in developing the 11-plus school admission test system in England and Wales (10 February, p 45). Phnom Penh is to the south-east of Bangkok (26 May, p 26). Joseph Banks was a naturalist and funder of James Cook s expeditions (26 May, p 45). Letters should be sent to: Letters to the Editor, New Scientist, 25 Bedford Street, London, WC2E 9ES Email: letters@newscientist.com Include your full postal address and telephone number, and a reference (issue, page number, title) to articles. We reserve the right to edit letters. New Scientist Ltd reserves the right to use any submissions sent to the letters column of New Scientist magazine, in any other format. 54 NewScientist 16 June 2018

MAKE Do try this at home RUSSEL COBB Smart table, dumb waiter Hobnobbing with friends? No need to get caught up in the kitchen when you can have food to go There are two things our local residents meetings take seriously: access to driveways and access to refreshments, says Sybil Dudee. But we can t all reach the coffee table and I can t vote on cycle paths when I m busy peddling cheese to my peers. I need the hostessing equivalent of a dropped kerb. We don t give much thought to coffee tables, they re just, well, part of the furniture. Yet they sit in the uncanny valley of serving space: not big enough to sit at like a dinner table, not small enough to put on your lap like a dinner tray. Perhaps there s a third way to ensure everyone gets a snack: bring the table to them. I started with the ubiquitous Ikea Lack the Times New Roman of coffee tables. It is ideal: lightweight and designed (and priced) for DIY. I gutted a children s ride-on electric car, and fixed the axles to the table legs. I left the comically large wheels attached for their aesthetic charm. The hefty motor can ferry snacks up to the weight of an average 3-year-old that should be more than enough biscuits for everyone. To give the table brains enough to navigate the room, I spliced a programmable Arduino into the circuitry. I then added optical sensors that let the robo-table see sharp transitions between different colours and so follow a line. Black tape on the light tiles in my bathroom worked well. But that s not normally where I serve refreshments. The edge of a rug placed in my living room proved less than eye-catching for my robo-table. Whenever it lost sight of the line, it wiggled back and forth hunting for it, scattering snacks as though planting a field of M&M s. To save snacks, I switched to a preprogrammed route to get my table to bus food around the room, although like many bus routes, the schedule could be a little erratic. By the third circuit of the room, robo-table had drifted perilously close to a pot-plant collision. No matter the battery will probably die before that happens. Some were less impressed. I had just got started on a return to kitchen refuelling button, when my housemate remarked it would be less effort to just put a bowl of crisps on the Roomba. Hannah Joshua For more Makes, visit newscientist.com/make 16 June 2018 NewScientist 55

FEEDBACK For more feedback, visit newscientist.com/feedback PAUL MCDEVITT HUMMING along to Macarena will not only put a spring in your step it could save lives. Enrique Carrero Cardenal at the University of Barcelona, Spain, and his colleagues found the upbeat tempo of the Spanish-language megahit by Los del Río is perfect for timing chest compressions when performing CPR. A study compared how accurately 164 medical students performed CPR on a mannequin over 2 minutes. One group received no help, another used a phone app to keep time, while the third used Macarena as a mental metronome. Although the app proved the best pacesetter for compressions, three-quarters of the Macarenaassisted group kept good time too, compared with only 24 per cent of those who got no assistance. Of course, any song with a tempo of around 100 beats per minute will suffice. In the UK, a popular choice for first aiders in search of a beat is the Bee Gees 1977 hit Stayin Alive. THE fashion industry is often criticised for the barely-there appearance of some catwalk models. But anyone watching footage of a recent fashion show in Jeddah, Saudi Arabia, found they couldn t see the women at all. Instead, empty dresses floated down the runway like wraiths, suspended from buzzing drones in front of an audience of men. Drones are certainly in fashion: a similar stunt by Dolce & Gabbana earlier this year saw airborne handbags whizz over the crowds. But the execution in Jeddah resembled less a futuristic vision of fashion than a dry cleaner s carousel. Still, it is one way to get the size zero look. It s not the first time Saudi Arabia has replaced women with robots: readers may recall animatronic mannequin Sophie was granted Saudi citizenship last year. While this was hailed as an Since nominative determinism has resurfaced, writes Graham Hagens, it may be appropriate to note that a large funeral service in South Africa is called Human and Pitt advance for androidkind, it is worth noting that if Sophie really is treated as a female citizen, she will have fewer rights to roam the country than an unemancipated Roomba. THANKSGIVING is a time when families in the US come together. But for those who don t see eye to eye with their relatives on political issues, the holiday came at an awkward time in 2016, just after Donald Trump s election victory. Now researchers have used smartphone location data from 10 million people to study how family gatherings were affected. They used geographical voting data to infer whether people were likely to have backed Trump or Hillary Clinton. Family members predicted to have voted for different candidates spent around 40 minutes less time together than those with the same political leaning, after controlling for factors such as travel distance. Republicans visiting Democrats shortened their stays more than Democrats visiting Republicans. Those living in areas exposed to heavy political advertising shortened their Thanksgiving visits by three times as much as others. Altogether, partisan differences were estimated to have cost people in the US a total of 74 million hours of Thanksgiving time with their families in 2016. This year, we recommend introducing a strict rule: no politics at the dinner table. THE tale related by Guy Cox, that translators substituted rib for penis bone in the account of Eve s creation, is amusing, says Reverend Peter Green, but quite apocryphal (26 May). Peter says there is no evidence that the Hebrew word tzela was used to mean baculum. In other contexts, tzela is used to describe a rafter, wall and even hillside. Considering that the word is fairly regularly used for a side of a building or a leaf of a double door, it is arguable that the writer is suggesting that God took Adam s entire side to make a mirror image woman to struggle alongside the man in equal partnership. A type of reproduction still enjoyed by sea anenomes, though with fewer heavenly hosts. A FREQUENT criticism of mainstream science reporting, writes Raffi Katz, is that the journalists have degrees in English and absolutely no idea about science. But in a similar vein, some science experts appear to struggle with English, he says. The following was a question my daughter brought home from school: Why does the fact that a periscope has two mirrors make what you see through it easier to understand? Raffi s daughter was quick to point out that if it only had one mirror it wouldn t be a periscope. Astute, but probably not the answer her science teacher is hoping for. Feedback supposes you could make a periscope with one mirror, perhaps for submarine commanders to keep a watch for overhead bombers. That the addition of mirrors makes things easier to understand is exciting, particular if it means funhouses can be granted academy status. MANY of you have written in to note the nominative determinism exhibited by President Trump across several definitions of the word. Now Howard Bobry informs us that Rear Admiral Fears is the new US homeland security and counterterrorism adviser. You can send stories to Feedback by email at feedback@newscientist.com. Please include your home address. This week s and past Feedbacks can be seen on our website. 56 NewScientist 16 June 2018

THE LAST WORD Last words past and present at newscientist.com/lastword Light at the limit People have been measuring the speed of light for a few hundred years, but the universe is nearly 14 billion years old. If the speed of light changes very slowly say a small percentage every 10,000 years how could we tell? If the speed of light varied over time, we would see supposedly constant astronomical processes taking place at the wrong rate, or even changing their rate. Imagine a small star orbiting a larger one, and that someone close by measures the orbital period as being exactly one Earth year. What would astronomers 100 light years away observe? If the speed of light is constant, the observed orbital period would remain at one year. But if the speed of light were increasing, light leaving the stars at the end of each orbit would be travelling faster than light leaving one year If the speed of light varied, constant astronomical processes would seem to proceed at the wrong rate earlier and would close the gap with it. Light pulses emitted a year apart would then arrive at Earth less than a year apart, meaning we would see each orbit as taking less than one year a mismatch between physics and observation. If the rate of change in the speed of light was accelerating, each orbit would be observed to be shorter than the one before, and the physicists would be even more unhappy. Conversely, if the speed of light was decreasing over time, light leaving the stars at the end of each orbit would be travelling slower than light leaving one year earlier, and would lag further behind. Now we would observe the orbital period as exceeding one year. Each orbit might even be observed to take longer than the one before. However, stellar orbits remain constant to the limits of our measurement technology, so we can say that if the speed of light is changing, the change is too small to observe. Richard Whybray Omagh, Tyrone, UK Perhaps the issue is not the speed of light, but the speed of time. As the universe expands, the matter within it becomes more spread out. Gravitational time dilation, as predicted by Einstein, causes time to speed up or slow down depending on proximity to a source of gravity: the greater the gravity, the slower the rate at which time flows. This could create the illusion that the expansion of the universe is accelerating something often attributed to the existence of socalled dark energy. A simpler explanation is that as the universe expands and becomes less dense, time itself speeds up. Conversely, at the time of the big bang, when all matter was in a very dense state, time would have been passing very slowly compared with where we are now. Cosmologists tell us that the initial big bang expansion was very fast. In fact, depending how you look at it, the opposite may be true. Furthermore, the estimate for the age of the universe (nearly Light s speed is defined to be 299,792,458 metres per second, so there s no way it can change with time 14 billion years) assumes time runs at a constant speed. This may also need to be re-evaluated. Mycal Miller London, UK We need to talk about a more basic question: what do we mean by the speed of light or its numerical value? We say that it is 299,000-and-something kilometres per second, but what is a kilometre and what is a second? Originally, a kilometre was one- 10,000th of the distance from the equator to the pole, and a second was one-86,400th of a day. So the metre was based on the size of a physical object Earth and the second on Earth s rotation period. Later we defined the metre in terms of wavelengths of a certain kind of light, and the second in terms of the period of another kind of light. Now we define the metre as the distance that light travels in a second divided by 299,792,458. So by our present definitions, the speed of light is 299,792,458 metres per second, and there is no way it can change with time. If we went back to defining the metre in terms of the size of some physical object made of atoms, then it could conceivably change with time. This comes down to questions such as whether the fine structure constant (relating the charge of an electron, Planck s constant and the speed of light) or the ratios of masses of the electron, proton and neutron are changing with time. These are meaningful questions; the question of whether the speed of light has changed is perhaps less so. Eric Kvaalen Les Essarts-le-Roi, France We have covered the possibility that the speed of light might vary over time (4 March 2017, p 28) Ed This week s questions FOBBED OFF When I use the electronic key fob to lock or unlock my car, no other car parked nearby has its locks activated. This is as it should be, but how does the system work? Philip Shields Southampton, UK UNSEEMLY SEAMS When I buy a new cotton vest or T-shirt, the side seams are always straight and parallel. After a few washes, one piece of material seems to move relative to the other, and the seams are never again parallel. Why is this? Stewart Hawkins Shirley, Surrey, UK We pay 25 for every answer published in New Scientist. To answer a question or ask a new one please email lastword@newscientist.com. Questions should be scientific enquiries about everyday phenomena, and both questions and answers should be concise. We reserve the right to edit items for clarity and style. Please include a postal address, daytime telephone number and email address. You can also send questions and answers to The Last Word, New Scientist, 25 Bedford Street, London, WC2E 9ES. New Scientist Ltd retains total editorial control over the published content and reserves all rights to reuse question and answer material that has been submitted by readers in any medium or in any format and at any time in the future. All unanswered questions and previous questions and answers are at newscientist.com/lastword/