23 March 2019, No3222 New Scientist (Australia)

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Anna Remington Is autism a gift?

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GAIA REBORN

The idea of Earth as one organism is back

OH MY COD!

Do you know what fish you’re eating?

THE HUMAN COMPASS

How our brains detect magnetic fields

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QUANTUM THEORY IS IN TROUBLE And it looks like the problem is you

INTERGALACTIC TRAVELLERS

There are trillions of ‘Oumuamuas out there 1 2

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THE WALLACE LINE: WHERE MARSUPIALS MEET MACAQUES EXPLORE DIVERGENT FORMS OF LIFE ON THE FAUNAL BOUNDARY BETWEEN ASIA AND AUSTRALIA WITH IAN MORRIS OAM The central islands of Indonesia - between Java, Bali and Kalimantan (today known as Borneo) to the West, and Papua at the eastern end of the country - are a place of wonder, a breathing laboratory for the study of evolution. The meeting of Asian and Australian ecosystems is known to biogeographers as Wallacea. In the mid-nineteenth century a titan of 19th-century British science, Alfred Russel Wallace discovered a mysterious line that separated two faunal universes. This line separated elephants and tigers from marsupials and honeyeaters from barbets and trogons. His observations of zoological differences to the northwest and southeast of this imaginary line through the Indonesian island of Sulawesi were part of a body of work that, alongside Charles Darwin, reinvented biology when he developed his theory of natural selection. Wallacea first sparked the curiosity of zoologist, author and inimitable travel guide, Ian Morris, during his early life as a teacher in East Arnhem Land where he encountered Indigenous students with genetic links to Makassan trepangers. “The precise dates of contact with outsiders have long been the subject of dispute, with both Aboriginal & Makassan oral histories indicating that trading began as far back as a thousand years before European colonisation. The Yolungu people of Arnhem land recount stories of the Makassan visitors and images of their boats are recorded in rock art” explains Morris.

Komodo Dragon on Komodo is, Ian Morris (inset)

“What’s extraordinarily unique about this place is that although the Indo-Australian Archipelago occupies only 4% of the planets land area, its home to nearly one quarter of all terrestrial land species and the most species-rich coral reefs in the world”. Sulawesi, the largest island in Wallacea, is the undiscovered paradise of Indonesia’s less visited islands. As the oldest and largest island within Wallacea, the island formerly known as Celebes hosts a rich fauna with many species that are unique to the island. Although its fauna is predominantly Asian in origin, it is the only island in south-east Asia with marsupials (the bear cuscus and dwarf cuscus), a distinctively Australian element. Exotic wildlife includes at least seven species of macaques unique to the island. There also exist several species of Tarsiers, including the smallest primate in the world which fits in the palm of your hand. Reptile diversity is high, and the best-known reptile in Wallacea is the Komodo Dragon, (Varanus komodoensis) or ‘ora’ in the local language, and you can find miniature buffaloes, or anoas, whose lovable appearance is said to hide an aggressive demeanour. And there are enigmatic wild pigs, babirusas, with wrinkled skin and impressive upper tusks that instead of growing down, grow up and backwards toward the skull penetrating through the surface of its upper lip. Today, you can visit the islands of the Archipelago and follow in Wallace’s footsteps. “Of many of these islands, thousands are difficult to travel to owing to their archipelagic spread,” says Morris. “Together with other seasoned adventure seekers, I feel fortunate to share insights with intrepid travellers who follow in the footsteps of the British field biologist Alfred Wallace on the small ship expedition vessel Coral Adventurer.” “But where Wallace undertook his voyages in small and primitive “phinisis” assisted by crew members who would often deceive or desert him, and managing illness, fever, hunger and extreme weather conditions; I am fortunate to share my knowledge with explorers in comfort that is much easier to handle.” We cross these seas in a sophisticated expedition vessel with the latest navigation equipment, and a shallow draft with manoeuvrability unmatched by larger ships. Expedition by small ship is a fitting way to explore Wallacea and all its wonders since you can travel to small, far-flung isles rarely seen by visitors”.

Enjoy

25% off As a travel guide and expert biologist, Ian accompanies Coral Expeditions’ voyages through the Indonesian Archipelago, interpreting the flora and fauna of regions from the Spice Islands and West Papua through to Sulawesi.

your cruise fare as a New Scientist reader. Quote promo code NSO#25

Wallace’s Line

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SPICE ISLANDS DAY 2 > Cenderawasih Bay

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Like Wallace’s famous book The Malay Archipelago, you can begin in Singapore before travelling east to the Malaysian state of Sarawak on the western coast of Borneo. Here, just near the capital of Kuching – City of Cats – you’re just upriver from Santubong National Park where Wallace wrote up the Sarawak Law. You can look out to the shallow waters and remember that you are, geologically, still connected to the Asian continent. Behind you, the immense rainforests of Kalimantan hide countless species awaiting discovery and on the far side of the mountains, the Makassar Strait marks that important transition point. Looking east, the islands of Wallacea await – Lombok, Timor, Ternate, the Moluccas and Spice Islands and many more. You’ll have woodpeckers to the west and parrots to the east. You could spend a lifetime studying the animals of these tropical islands and waters, and yet there’d be many more to find still. There’s no better laboratory for studying biogeography under the tutelage of a passionate expert than this archipelagic constellation between two continents. - A journey through the Indonesian archipelago is a feast for the senses. Explore these destinations with Coral Expeditions aboard the expedition ship Coral Adventurer.

We awoke with anticipation at Cenderawasih Bay. Our local guide whizzed off in the zodiac to talk to the local fisherfolk on their unique wooden ‘bagan’ platforms. He came back with good news – whalesharks spotted! We were soon in the clear water and snorkeling with six huge whale sharks swimming lazily beside us. It was truly awe-inspiring to be in close proximity to these gentle giants, and the encounter had us beaming for hours afterwards. I suspect it is a story we will recount for many years to come.

Spice islands & Raja Ampat > 12 Nights, All inclusive aboard Coral Adventurer > Darwin to Biak departs 21 December 2019 > Biak to Darwin departs 02 January 2020 1800 079 545 [email protected] www.coralexpeditions.com

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34 Gaia reborn The idea of Earth as one organism is back

5

12 Oh my cod! Do you know what fish you’re eating?

News 6

8

The human compass How our brains detect magnetic fields

28 Quantum theory is in trouble And it looks like the problem is you 15 Intergalactic travellers There are trillions of ‘Oumuamuas out there Plus 20,000 mountains under the sea (8). The mystery of 33 (16). James Bond goes electric (24). Otter archaeology (19)

When considering our origins, it is best to keep an open mind. We should celebrate flaws in quantum theory

8

THIS WEEK Bullying is widespread in science. First woman wins Abel maths prize. Cyclone hits Mozambique NEWS & TECHNOLOGY Can humans sense magnetic fields? 20,000 mountains under the sea. Amazon logging. We missed a meteor strike. Society influences risky behaviour in kids. The first Australians. Fake fish. Smart bacteria halt spread of cancer. Interstellar planet builders. Keeping your DNA data from the FBI. Climate change will make it harder to predict rain. The mystery of 33

19 IN BRIEF Sea otter archaeology. Spontaneous waterfalls. Actors live their roles. ISS gets a very clean toilet. New frog found

Analysis

Features 28 Quantum theory is in trouble A new twist on a classic thought experiment reveals a flaw 34 Gaia reborn Could an unorthodox form of evolution have made Earth just right for life? 38 Super-sized income Getting your children to eat food on camera is a lucrative business

Culture 42 Exposed minds Surveillance capitalism is changing human nature forever. PLUS: this week’s cultural picks 44 A chilling tale How money and politics beat science to create climate change denial in the US

Regulars 26 APERTURE Spiky space antenna 52 LETTERS We will need carbon capture 55 FROM THE ARCHIVES The advent of Prozac 56 FEEDBACK Sky high food 57 THE LAST WORD Dunny roaming

22 INSIGHT We need to find ways to stop drones disrupting airports 24 COMMENT First all-women spacewalk finally here. Why James Bond is driving an electric car 25 ANALYSIS How to understand the scary air pollution numbers 23 March 2019 | NewScientist | 3

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Further, faster, earlier When considering our origins, it is best to keep an open mind HAVE humans been in Australia twice as long as we thought? The discovery of what look like two hearths is tantalising (see page 10). Yet even the researchers acknowledge: “In the absence of bones, stone flakes or any independent trace of people, the notion of occupation at 120,000 years ago currently remains difficult to credit.” So why all the fuss? We have been here before. Two decades ago, The Sydney Morning Herald broke the story that 176,000-year-old stone tools had been found in Australia’s Northern Territory. The dates were considered

outlandish. “If modern humans evolved in Africa, they must have invented the bicycle at the same time so they could cycle around to catch the first rafts to Australia,” quipped one palaeoanthropologist. That earlier research has since been largely dismissed. But now everything has changed. Fossils found in Morocco indicate that Homo sapiens evolved at least 300,000 years ago – 100,000 years earlier than was thought. People were living in south India some 180,000 years ago, and reached China by 120,000 years ago. Long before that, Asia was

Schrödinger’s kittens THERE is a famous quote about quantum theory. Fittingly for a discipline where uncertainty is the stock-in-trade, no one quite seems to know what form it originally took or who first said it. But it goes along the lines of “if you think you understand it, you haven’t understood it”. Mindful of this sentiment, we will reserve judgement as

to whether the Schrödinger’s-caton-steroids thought experiment lately served up really is the existential threat to quantum theory – or perhaps our sanity – that some claim (see page 28). But we applaud both its spirit and the lively debate it has engendered. Yes, you might argue the world has more pressing concerns. Yes, you might say, “if it ain’t broke,

teeming with other hominins, including Neanderthals, Denisovans and “transitional forms”. Ancestors of the diminutive “hobbit” must have sailed or rafted to the Indonesian island of Flores some 700,000 years ago. Everywhere we look, our preconceptions about human evolution and migration are being overturned. Our ancestors travelled further, faster and earlier than we ever imagined. Their early arrival in Australia may be “difficult to credit”, but if recent discoveries have taught us anything, it is to keep an open mind. ■

don’t fix it”. Quantum theory is by any measure the most successful picture of basic reality we have ever had. But maxims for life rarely translate to science. It was pulling on a few seemingly trivial threads that caused the tapestry of classical physics to unravel. The improved understanding we gained led to quantum innovations from lasers to computers. If you believe in human progress, this unravelling is where it starts. ■ 23 March 2019 | NewScientist | 5

THIS WEEK

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Cyclone Idai strikes AS MANY as 1.7 million people may be affected after Cyclone Idai hit Mozambique, in what a UN spokesperson says is shaping up to be the worst weather-related disaster on record in the southern hemisphere. According to president Filipe Nyusi, at least 1000 people may have been killed by the cyclone. The country’s government says 100,000 people urgently need to be rescued. “The scale of damage caused by Cyclone Idai that hit the Mozambican city of Beira is massive and horrifying,” the International Federation of Red Cross and Red Crescent Societies (IFRC) said in a statement on 18 March. Beira, a port, was hit by the category-two storm late on 14 March, with winds of about 175 kilometres per hour. Rivers burst their banks,

killing people and flooding nearby areas. The IFRC estimates that 90 per cent of the area has been damaged. As many as 1500 people may have been injured. “Communication lines have been completely cut and roads have been destroyed. Some affected communities are not accessible,” said Jamie LeSueur of the IFRC assessment team in a statement. “Beira has been severely battered. But we are also hearing that the situation outside the city could be even worse,” he said. “Yesterday, a large dam burst and cut off the last road to the city.” After its landfall in Mozambique, the cyclone swept inland through Malawi and Zimbabwe, where it is reported to have killed about 150 more people, and injured 700 more.

Videos of massacre proliferate online

Hen harriers go missing on moors

MATHEMATICIAN Karen Uhlenbeck has become the first woman to win

HEN harriers are being illegally killed in significant numbers in

convicted of illegally killing one. Stephen Redpath at the University of Aberdeen, UK, and his colleagues fitted 58 hen harriers with tags and tracked them between 2007 and 2017. Four died in suspicious

the Abel prize, sometimes called the Nobel prize of mathematics.

the UK, a new analysis suggests. These birds of prey are struggling

circumstances, and 38 simply disappeared: their transmitters

at two mosques in Christchurch, New Zealand. It is the worst massacre

She has been awarded the 6 million Norwegian kroner ($700,000) prize

to survive in England and many conservationists believe illegal killings

stopped working without warning, and no body could be found (Nature

in the nation’s recent history. The suspected attacker, an

for her work in the fields of gauge theory and geometric analysis, which

are a factor. The prime suspects are the managers of grouse moors, where

Communications, DOI: 10.1038/ s41467-019-09044-w).

Australian man, broadcast the shootings in a live stream on

have been credited with far-reaching impact in mathematics and physics.

grouse – which hen harriers eat – are reared for recreational shooting.

The birds were statistically more likely to vanish while on a grouse

Facebook. Although his account was disabled after New Zealand police

Gauge theory underpins much of modern theoretical physics, and is integral to cutting-edge research in particle physics, general relativity and string theory. Her work laid the foundations for one of the major milestones of 20th-century physics, the unification of two of the four fundamental forces of nature: electromagnetism and the weak nuclear force. “The holy grail in physics has always been unification of forces,” says Jim Al-Khalili at the University of Surrey, UK. “She has made a big contribution to the mathematics that allowed us to progress some considerable way along this path.”

Reports that harriers have vanished are common, but nobody has been

moor. “It strongly suggests there’s illegal killing going on,” says Redpath.

alerted the firm, copies of the footage rapidly resurfaced, reposted by users of Reddit, Twitter and YouTube. These platforms have scrambled to remove the video from their sites. The original was viewed about 4000 times, but in the first 24 hours after the attack, Facebook removed 1.5 million copies of it, the firm said. The rapid proliferation of the video highlights the ongoing challenge that tech companies face in managing potentially harmful content. New Zealand’s prime minister Jacinda Ardern, among others, has called on social media platforms to take greater responsibility in tackling content that incites violence or hate.

6 | NewScientist | 23 March 2019

BLICKWINKEL/ALAMY

First woman wins Abel maths prize

ON 15 March, 50 people were killed and dozens wounded in attacks

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

Science’s dark secret is out Survey reveals extent of bullying, discrimination and harassment in science

A QUARTER of people working in science have experienced sexual harassment, bullying and discrimination over issues ranging from disabilities to diet. The 2019 New Scientist/SRG Salary Survey polled nearly 3700 people across Europe and North America who worked in academia, industry and government agencies. The data revealed a gap of about £10,000 between the average salaries of male and female respondents in the UK. Of the countries surveyed, discrimination and harassment seems highest in the US and Canada. Twenty nine per cent of respondents in North America said they had experienced this at work, compared with 19 per cent of people in the UK and 25 per cent in the rest of Europe. Across all regions, respondents were most likely to say they had

“To speak up against scientists who are eminent leaders in their field requires strength” experienced discrimination and harassment on the basis of gender, followed by age and race. Men and women both reported encountering such behaviour: in the UK, 23 per cent of women said they had experienced discrimination and harassment, compared with 15 per cent of men. Hollywood’s “Me Too” movement against sexual harassment has spread to many other areas of society. Twitter users have used the #MeTooSTEM banner to allege that some highprofile researchers have harassed and bullied with impunity. Several survey respondents told New Scientist that they

CAVAN IMAGES/GETTY

Clare Wilson

believe the career structures within academia make this kind of behaviour more likely to go unchecked. One of the biggest problems may be that senior university researchers bring in large grants from research funders to their institutions. “The power is often with the money,” comments Laura Norton at the Royal Society of Chemistry. This can be compounded by hierarchical power structures. “Group leaders are often seen as eminent leaders in their field,” says Norton. “To speak up against those people requires strength.” Even researchers who aren’t a big name have a lot of power over those at the early stages of their career – someone doing a PhD, for instance, is beholden to their supervisor. This was a problem for Tina (not her real name), who believes that her PhD supervisor sabotaged her thesis because he was sexually interested in her and wanted to prolong their relationship. She says he made comments

about her body, bought her dresses that he asked her to wear to dinner, and repeatedly told her she needed to restart her thesis from scratch without giving her constructive advice on how to improve it. Tina says the stress eventually began to affect her health, and when her PhD funding ran out she felt she had to leave without completing her thesis.

Zero tolerance The survey uncovered bad behaviour in industry, too. While working in quality control for a chemicals manufacturing firm, Pete (not his real name) says he had to put up with a colleague repeatedly asking if he was gay. At one time, the man made up a rhyme calling Pete a paedophile. Pete complained to his manager, but nothing was done. Others said they faced discrimination for having disabilities or even for being vegan. Scientific bodies are starting to act on the problem. In the US, the

National Science Foundation and the National Institutes of Health have announced efforts to clamp down on sexual harassment at institutions that receive their research grants. The UK’s Wellcome trust, one of the world’s biggest charitable funders of medical research, last year said it would pull grants from people or institutions found guilty of any kind of bullying. Last year, the Royal Society of Chemistry suggested all funders should take this approach. The cross-institution body Universities UK (UUK) has set up a task force to tackle harassment of students, but this doesn’t cover non-students and no institution is obliged to follow its advice. “We know that more needs to be done and UUK’s work in this area is ongoing,” a spokesperson said. “We have called on everyone in the community to enforce a zero-tolerance approach,” says Norton. “Without doing that you’re enabling a culture that some people would call toxic.” ■ 23 March 2019 | NewScientist | 7

NEWS & TECHNOLOGY

We may sense magnetic fields In the study, each participant shut their eyes while researchers measured alpha waves – a type of brain activity that is present when we are awake but relaxed – before and after a 100-millisecond change in magnetic field. They recorded a drop in the amplitude of alpha waves in some people after a magnetic field pointing downwards was rotated

Donna Lu

Plenty more mountains in the sea THOUSANDS of previously uncharted underwater mountains have been discovered. They are included in the most detailed map of the ocean floor ever produced. The submerged peaks, also known as seamounts, were identified by a team led by David Sandwell and Brook Tozer at the Scripps Institution of Oceanography in San Diego, California. 8 | NewScientist | 23 March 2019

Does your brain have an internal compass?

team member Isaac Hilburn. Claims that humans can naturally detect magnetic fields have long been a source of controversy, but some other researchers are cautiously optimistic about the new work. The team’s approach parallels studies of magnetoreception in animals, says Nathan Putman at LGL, an ecological research firm based in Texas. Putman, who studies marine animals including turtles, says the strongest evidence for a magnetic sense is when animals change their direction of travel in response to an altered field. The possibility that humans could have a magnetic sense is exciting, but the results will need to be replicated, says Putman. “A sceptic could argue that there are a lot of reasons why brainwaves might change and it may not have anything to do with orientation.” It is possible the EEGs could have picked up disruptions from the surrounding environment, says Can Xie at Peking University in China, although the study tried to avoid this, he says. “It is hard to interpret the EEG signal precisely, which makes it difficult to further explore the underlying molecular mechanism at this stage.” If the results hold up, it may mean that a magnetic sense played a role in the nomadic lives of our hunter-gatherer ancestors, says Hilburn. ■

the ocean than flat seabed does. This results in a slight difference in sea surface height. Satellites can accurately measure these differences to infer when seamounts exist below. Measurements like this were used for a 2014 map that contained approximately 10,000 seamounts, but the new map uses more accurate data. For example, it uses readings from the French-Indian AltiKa sensor,

which was launched on a satellite in 2013. This instrument can measure the distance to the sea surface to within 21 millimetres – which is twice the accuracy of previous sensors. In 2014, we could use this technique to map all the seamounts more than about 2 kilometres tall. Today, we can do so for those taller than 1.5 kilometres, says Sandwell. He says thousands more seamounts are likely to be detected after NASA’s SWOT satellite launches in 2021. SWOT should be able to find underwater peaks that are just 1 kilometre tall. David Hambling ■

KLAUS VEDFELT/GETTY

WHAT do birds, bees, fish and wolves all have in common? A magnetic sense that helps them navigate. Now it seems we may have some form of this ability too. Joseph Kirschvink at the California Institute of Technology and his colleagues have found that altering the direction of nearby magnetic fields causes temporary changes in human brain activity. Their study involved using electroencephalography (EEG) to record the brain activity of 29 participants sitting in a dark room, while electromagnetic coils were used to create magnetic fields. The experiment mimicked the magnetic field changes we are subject to when we move about in the real world, says Kirschvink. The direction and intensity of Earth’s magnetic field varies by geographical location. For example, at the magnetic north pole, the direction of the field points vertically down, into the ground. In the wider northern hemisphere, this vertical angle changes, but the magnetic field is always skewed downwards.

horizontally in a counterclockwise direction. These brain responses occurred at an unconscious level – participants weren’t able to detect when or if any changes occurred. However, no participants showed brain changes when the field was rotated clockwise, a finding the team can’t explain. Rotating an upwards-pointing magnetic field – like that in the southern hemisphere – didn’t cause a change either (eNeuro, doi. org/c3ns). The team speculates this may be because participants’ brains were attuned to the field in the northern hemisphere, where the study took place. “One way to test this hypothesis would be to reproduce our experiment in the southern hemisphere,” says

Their new topographical map has uncovered more than 5000 new seamounts and possibly as many as 10,000. The updated map will be valuable for climate modelling and tsunami prediction. This is because seamounts can affect ocean currents that influence climate and can be the scene of huge underwater landslides. Only about 10 per cent of the seabed has been mapped with sonar. The rest is mapped by measuring the effects of gravity on the sea’s surface. This is possible because seamounts exert a greater gravitational force on

“Most of the seabed is mapped by measuring the effects of gravity on the sea’s surface”

For daily news stories, visit newscientist.com/news

Amazon logging may raise local temperatures

amount of sunlight reflected and the rates at which water evaporates from vegetation into the atmosphere. The degree of warming may vary dramatically within the Brazilian Amazon. Some parts of the east, where there is an “arc of deforestation” hundreds of kilometres wide and thousands of kilometres long, could see big local temperature rises even if logging is reduced. In that scenario, where 79,000 square kilometres of trees are cleared by 2050, large tracts of forest won’t get significantly warmer. With business-as-usual deforestation, however, in which 606,000 square kilometres of rainforest disappears, local temperature rises could be widespread. An increase in this logging could make matters much worse. “Any more deforestation and conversion to agriculture will exacerbate these numbers,” says Sinervo. Adam Vaughan ■

SIMON PROUD, UNIVERSITY OF OXFORD/JAPAN METEOROLOGICAL AGENCY

THE speed at which trees are being cleared in the Brazilian Amazon today could have a similar local warming effect to decades of temperature rises driven by climate change. So say calculations on how deforestation will alter temperatures in the region over the next three decades. Logging has been expanding in Brazil. And the election of populist Jair Bolsonaro as president in January has provoked fears that deforestation could get even worse if he appeases the powerful agribusiness lobby. Barry Sinervo at the University of California, Santa Cruz, and his colleagues have calculated that even with current tree losses, local surface temperatures in the Amazon will rise by an average of about 1.5°C between 2010 and 2050. That will come on top of the 2°C of warming from climate change that the world is on track for by mid-century (PLoS One, DOI: 10.1371/journal.pone.0213368). Deforestation affects local temperatures by changing the

A meteor’s smoke trail was captured by a weather satellite

Huge meteor explosion unnoticed for months A METEOR caused a massive acoustic waves inaudible to explosion over Earth last year, but humans. These stations were set nobody noticed until now. It is the up during the cold war, initially second-largest recorded blast in to detect nuclear explosions. the past century, after the meteor After newscientist.com that exploded over the Russian reported on the meteor last week, region of Chelyabinsk in 2013. Simon Proud at the University of The giant fireball lit up at Oxford found images of it taken 2350 GMT on 18 December over by a Japanese weather satellite the Bering Sea, a part of the Pacific (above). It is the third-largest Ocean between Russia and Alaska. “The meteor was detected Peter Brown at Western by stations set up during University in Canada spotted the the cold war to detect meteor in measurements picked nuclear explosions” up by at least 16 monitoring stations globally. The meteor was 10 metres blast in modern times, after across, had a mass of 1400 tonnes Chelyabinsk and a massive and impacted with an energy of explosion that occurred in Siberia, 173 kilotons of TNT, he wrote on Russia, in 1908. Known as the Twitter. The energy was about Tunguska event, the air burst 10 times that of the atomic bomb flattened an estimated 80 million dropped on Hiroshima in 1945. trees over an area of more than The meteor exploded at 2000 square kilometres. altitude above Earth’s surface, “When you see these says Alan Fitzsimmons of Queen’s infrasound waves, you know University Belfast, UK. “It would immediately that there has been have been quite spectacular,” he an impact or a large release of says. The blast was detected by energy,” says Fitzsimmons. infrasound stations worldwide, Triangulating the location and which pick up low-frequency source of an explosion requires

combining pressure-wave data from multiple monitoring stations, which may explain the delay in the data being made public. The Bering Sea explosion was also picked up by US government monitors that detect fireballs: their sensors spot electromagnetic radiation in the form of infrared and visible light. Various monitoring groups regularly survey the sky for near-Earth asteroids, says Chris Mattmann at NASA’s Jet Propulsion Laboratory in California. NASA uses a system that scans a catalogue of known asteroids for possible impacts over the next century. Small objects frequently hit Earth, says Brandon Johnson at Brown University in Rhode Island, and because 75 per cent of Earth is covered by oceans, many go unreported. Large impacts are rare, because bigger asteroids are less common. But sky surveys of asteroids of between 5 and 50 metres in diameter suggest that these objects should hit Earth less frequently than they actually do. “It implies that there may be more small asteroids than we’re actually seeing in those telescopes,” says Fitzsimmons. Current telescopes are more accurately able to detect objects of several hundred metres or larger in diameter, and less sensitive to smaller objects – but this will change in the future as technology improves, he says. Asteroid monitoring may also be affected by space junk, particularly the increase in satellite numbers as miniature satellites become commercially available, says Mattmann. “We really should try to track more bodies to smaller sizes so that we have a better understanding of the threat from these kinds of air blasts,” says Johnson. Donna Lu ■ 23 March 2019 | NewScientist | 9

NEWS & TECHNOLOGY vegetation growing there. The burnt stones are lying on top of bare rock, which means the fuel for the fire had to be imported.

Kids learn risky behaviour at school

chance of scooping a larger prize.

“Although these gender differences exist, they are small and most women and men act the same” Among the youngest Mosuo children, girls tended to favour riskier choices than boys. However, this pattern was reversed in older Mosuo children. Among Han children, boys tended to favour riskier ticket choices than girls, and this didn’t change with age (PNAS, doi.org/c3nb). The results show that Mosuo children are influenced by their Han peers rather than biological factors, says Liu. Although these gender differences exist, they are small and most women and men act the same, says Julie Nelson at the University of Massachusetts. Yvaine Ye ■ 10 | NewScientist | 23 March 2019

INTERVIEW

120,000-year-old Australians be one explanation, but there is a big abalone and seabirds today don’t carry abalone shells around. The dominant line of evidence is the extensive use of fire. We found lots of blackened stones, which originally started as pale limestone, and they are blackened as the result of intensive heat.

Ruby Prosser-Scully

DID humans live in Australia 60,000 years earlier than we thought? Newly discovered shells and blackened stones suggest so, according to James Bowler at the University of Melbourne. In 1974, Bowler discovered the roughly 40,000-year-old Mungo Lady and Mungo Man, the oldest human remains ever found in Australia. Subsequent genetic evidence and human artefacts have since placed the arrival of humans in Australia at 60,000 years ago. But in six new papers, Bowler and his colleagues have described what they believe to be two hearth-like areas of blackened sand, charcoal and darkened stones in south-west Victoria, dating back to 120,000 years ago (Proceedings of the Royal Society of Victoria, doi.org/c3mz). Why do you think humans could be responsible for what you have discovered?

There is an accumulation of shells of edible sea animals. Birds could

Could this have been caused by wildfires or lightning?

There are no plants there: no root channels and no remnants of any Bowler is studying sites near the Hopkins river estuary (above)

UNIVERSITY OF MELBOURNE

was guaranteed to win a small prize, while ticket 6 had a 50 per cent

How do we know the site is 120,000 years old?

DAVID FOSTER/ALAMY

MEN are more likely to engage in riskier behaviours than women, or so the stereotype goes. However, a study with children adds weight to the idea that such differences are shaped by society, not written in stone. To find out how gender may affect risk-taking behaviours, Elaine Liu at the University of Houston in Texas and Sharon Xuejing Zuo of Fudan University in Shanghai visited a small town in south-west China, where children from two ethnic groups — Mosuo and Han — attend school together. These two groups have different traditional gender norms, with women typically heading Mosuo families, whereas men typically take this role in Han families. Liu and Zuo asked 352 children in the town to play a lottery game. The 7 to 12-year-olds had to select one of six lottery tickets, labelled 1 to 6, with the higher the number, the riskier the choice, but the bigger the possible reward. For example, ticket 1

There are three lines of evidence, including geological evidence of sea level, all independently providing the same age. People will not argue about the age, they will argue about whether it is people or whether it is nature. There are no stone tools – though there are no hard rocks in that area suitable for making tools, so that’s not surprising. There are no bones and no human remains. It is a frustrating conclusion to 11 years of work, but I’m convinced that continuing research will find definitive evidence. If the site is confirmed as ancient human activity, what does that tell us about our species’ history?

It opens up a can of worms for the understanding of when people came out of Africa. It is a long way from Africa to the southern coast of Australia. They would have had to cross water to get from Indonesia to the Australian mainland, but they wouldn’t have been the first to do that, because Homo erectus did that to get to the Indonesian island of Flores. Is the hunt now on to find similarly ancient sites?

Undoubtedly. This evidence, circumstantial as it is, will inspire a lot of archaeologists to open their hearts and minds to that older level in the Australian landscape, which previously has been blocked out of any exploration because of our implicit understanding that nobody was here beyond 50,000 or 60,000 years ago. In the past, people like myself – geologists, archaeologists – would never have looked at events at 120,000 years ago with any chance of finding human occupation. All that, I believe, has now changed. ■

NEWS & TECHNOLOGY

Net closing on the fake fish problem IS THAT really wild-caught, Atlantic cod on your plate or, as it turned out in a restaurant in Belgium, farmed catfish? On average, 30 per cent of fish sold in shops and restaurants globally is wrongly labelled, with as much as half misdescribed in some places, according to a 2018 review. Now it seems that eco-labelling schemes could be a possible fix to avoid fakes. A study by the Marine Stewardship Council (MSC) has found that less than 1 per cent of seafood bearing its sustainability mark was mislabelled. This was determined using DNA tests on 1402 products sold in 18 countries between 2009 and 2016. Consumers are often in the dark over where their fish comes from, which can have serious health and sustainability implications. Some of the worst examples have included toxic pufferfish being sold as monkfish and endangered whale meat

Smart bacteria halt spread of cancer in mice GENETICALLY modified “smart” bacteria injected into tumours can shrink growths and trigger an immune response that stops cancer spreading, tests in animals show. The engineered bacteria exploit the vulnerability of solid tumours to infections. This vulnerability comes about because tumours evolve all kinds of tricks for evading immune system attack, from physically keeping out immune cells to releasing chemicals that tell the cells not to attack. But this leaves tumours open 12 | NewScientist | 23 March 2019

fish passed off as more expensive ones. Deliberate mislabelling across all seafood is estimated to involve billions of pounds of sales globally. “That average 30 per cent [of all fish mislabelled] gives you no indication of whether it is deliberate or unintentional,” says Francis Neat of the MSC. But there are ways to get at the truth. “We can do the tracebacks [through the supply chain] and figure out where the substitution occurred, and whether it is for financial gain or not,” he says. Eco labels are just one way to avoid being duped. Education also helps. Few customers of fish and chip shops in the UK, for example, know that rock salmon, which is often on the menu, is another term for dogfish, a type of shark that is overfished. “People should know where their fish was caught, how and when, and what species it is. If you don’t know those things, you can’t make informed choices on whether you can eat it with a clear conscience,” says Callum Roberts at the University of York, UK. He also points to the limits of DNA testing, which can tell species apart but can’t tell whether a fish comes from a sustainable stock. ■

being passed off as fatty tuna. “People know about it, the question is what do you do about it,” says Jaco Barendse at the MSC. All the wrongly labelled seafoods bearing the MSC logo were found to be white fish, including cod and hake, which can be easily mistaken for one

When trawling the shelves for your favourite fish, beware

to infection by bacteria and viruses that would be rapidly wiped out

triggering their destruction. However, CD47 is also found on the

to new sites in the body was greatly reduced (bioRxiv, doi.org/c3k5).

elsewhere in the body. The smart bacteria, created by Sreyan Chowdhury at Columbia University in New York and his colleagues take advantage of this, infecting a tumour and multiplying. Once the number of bacteria reaches a critical level, they are designed to self-destruct and release an antibody in the heart of the cancerous growth. This antibody then encourages the immune system to attack the tumour. The team started with a harmless strain of E. coli. This was engineered to produce an antibody, which binds to a protein called CD47 found on the surface of some cancer cells,

surface of healthy red blood cells, so injecting high levels of the antibody straight into the blood would be dangerous. By instead injecting the bacteria directly into tumours, high levels of the antibody are produced only where needed. In tests in mice, several kinds of tumours shrank after being injected with the smart bacteria. What’s more, the growth of tumours elsewhere in the body of the mice also slowed, while the chances of cancer spreading

The research shows that the modified bacteria can be used to trigger body-wide immune system targeting of untreated tumours, says cancer biologist Graham Dellaire of Dalhousie University in Canada. “Harnessing this effect could well be the key to curing metastatic disease – the major cause of cancer-related death,” he says. Whether this approach will work in people remains to be seen, but Dellaire points out that the live bacteria used to immunise against TB, in the BCG vaccine, have long been used to treat bladder cancer. This is also thought to work by triggering an immune response. Michael Le Page ■

SIMON DAWSON/BLOOMBERG VIA GETTY

Adam Vaughan

another (Current Biology, doi.org/ c3m2). The use of names on packaging such as snapper or skate, which cover up to 60 different species of fish, also doesn’t help. The study found just two examples of deliberate mislabelling among fish bearing its logo, with hoki swapped for hake, and haddock for cod. The motivation for misleading consumers is financial – cheaper

“Harnessing this could be key to curing metastatic disease – the major cause of cancer-related death”

Humanity will need the equivalent of 2 Earths to support itself by 2030.

People lying down solve anagrams in 10% less time than people standing up.

About 6 in 100 babies (mostly boys) are born with an extra nipple.

60% of us experience ‘inner speech’ where everyday thoughts take a back-and-forth conversational style. We spend 50% of our lives daydreaming.

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NEWS & TECHNOLOGY

ESA/HUBBLE, NASA, ESO, M. KORNMESSER

DNA-testing customers able to deny the FBI

Earth may contain interstellar rocks Leah Crane

University Belfast, UK, and Susanne Pfalzner at the Jülich Supercomputing Center in Germany found that these rocks could play a crucial role in planet formation if they get caught in a disc around another star. Many of the interstellar objects should move too fast to get caught, and most that do get trapped are likely to fall into the star. Nevertheless, the pair calculated that there should be

BITS of Earth may originally be from another part of the galaxy, having crossed light years to form the ground beneath our feet. That is the conclusion of a study suggesting that the Milky Way should be full of free-floating rocks like ‘Oumuamua, the interstellar asteroid that visited our solar system in October 2017. They may help form planets. Our conventional picture is that “A fraction of planets planets form out of discs of gas could have had an and fine dust around a star, but ‘Oumuamua at their heart. some observations seem to show It’s a lovely thought” them being born much faster than that model predicts. Objects like ‘Oumuamua may be the at least 10 million objects the size solution to this discrepancy. of ‘Oumuamua (about 100 metres Researchers have estimated across) or larger around every star that there should be about (arxiv.org/abs/1903.04451). 29 trillion ‘Oumuamua-like “It’s not a very efficient process, objects per cubic light year in our but you’re starting out with so galaxy, floating free after having many of them that you still end been thrown out of their orbits up with plenty,” says Bannister. around their home stars. They are Of the 10 million big interstellar likely to be relatively small, dark objects, thousands are likely to and fast-moving, which is why be more than a kilometre across, we have seen only one so far. and a few may be dwarf planets, Michele Bannister at Queen’s similar in size to Ceres or Pluto.

Interstellar objects like ‘Oumuamua could help form planets

The interstellar exiles could attract dust, pebbles and gas with their gravity and eventually become full-on planets. “A fraction of planets could have had an ‘Oumuamua at their heart,” says Bannister. “You’re not going to have any trace of it any more, but it’s a lovely thought.” This would skip the slow inconvenience of building planets out of tiny grains of dust. “It would accelerate the planetformation process significantly,” says Richard Alexander at the University of Leicester, UK. This mechanism would feed back on itself: systems with more planets kick out more rocks, which create more planets in other systems. “Planetary systems are helping build planetary systems,” says Bannister. If that is the case, it could explain why the earliest stars seem to have fewer planets than those that formed more recently. Early generations of planets could have formed the conventional way and then gone on to seed other planet-forming discs with discarded ‘Oumuamuas. Planet formation across the galaxy should continually increase as there are more and more stray rocks flying around. ■

A BIG home DNA-testing company has announced a way for its customers to stop law-enforcement agencies accessing their data. FamilyTreeDNA recently faced criticism when BuzzFeed News revealed that the company had chosen to cooperate with the FBI without consulting customers. Initially, the only way for people to deny the FBI access to their data was to opt out of the firm’s DNA-matching service, depriving themselves of a powerful tool for exploring their family tree. But on 12 March, FamilyTreeDNA told customers that they could now use the matching service but end access by law-enforcement agencies. “Users now have the ability to opt out of matching with DNA relatives whose accounts are flagged as being created to identify the remains of a deceased individual or a perpetrator of a homicide or sexual assault,” the company said in an email outlining changes to its terms and conditions for users. Law-enforcement agencies must now register through a special process to access the company’s matching service, FamilyTreeDNA said. The combination of genetic data from home DNA-testing kits and family tree databases has allowed individuals to find relatives by matching DNA. It has also helped police to solve crimes, such as last year identifying the man thought to be behind a series of murders in California during the 1970s. “It’s the lack of regulation and oversight I’m concerned about,” says Debbie Kennett at University College London, who is a customer of the firm. If the genetic information wasn’t held by private companies, but instead stored in a regulated, universal database, there would be more control and oversight over its use, she says. “At the moment, there’s nothing between the data and the police. It’s the Wild West.” Adam Vaughan ■ 23 March 2019 | NewScientist | 15

NEWS & TECHNOLOGY

Michael Marshall

SOME kinds of weather forecasting will be easier, and others harder, in a world made warmer by climate change. In particular, global warming will hamper predictions of when torrential downpours will hit the northern hemisphere. Weather forecasts have been steadily improving for decades. However, although we know the world is getting warmer because of our greenhouse gas emissions, almost nothing is known about how climate change will affect the weather’s predictability. “When you add energy to a system, you might intuitively expect it to become more turbulent and messier,” says Gabriele Messori at Uppsala University in Sweden. This would imply that the weather in a warmer world would be less predictable. But Messori says physics doesn’t always work in this intuitive way. To work out what is likely to happen, Messori and Sebastian Scher of Stockholm University in Sweden used a climate model to simulate two sets of conditions:

Centuries-old problem about 33 cracked ADD three cubed numbers, and what do you get? It is a question that has puzzled mathematicians for centuries. In 1825, S. Ryley proved that any fraction could be represented as the sum of three cubes of fractions. In the 1950s, Louis Mordell asked whether the same could be done for integers, or whole numbers. In other words, are there integers k, x, y and z such 16 | NewScientist | 23 March 2019

the climate as it was from 1976 to 2005 and as it could be from 2071 to 2100, assuming emissions continue rising at current rates. Then they took snapshots from both models and fed them into a weather-forecasting system to see if it could predict what would happen next. In both cases, they ran many forecasts to see how consistent these were. This “ensemble forecasting” allowed them to measure how predictable the weather was. If most of the forecasts were similar, the weather was predictable. If they were wildly different, it wasn’t. In the future climate scenario, the most dramatic changes were in the northern hemisphere. The average temperature and air pressure, which impacts wind, became slightly more predictable. But rainfall and other precipitation became less so (Geophysical Research Letters, doi.org/c3k7). Scher and Messori say the reason for the overall increase in predictability in this hemisphere is that the Arctic is warming faster than the equator, so the temperature difference between

that k = x3 + y3 + z3 for all possible values of k? We still don’t know. “It’s long been clear that there are maths problems that are easy to state, but fiendishly hard to solve,” says Andrew Booker at the University of Bristol, UK – Fermat’s last theorem is a famous example. Booker has now made another dent in the cube problem by finding a sum for the number 33, previously the lowest unsolved example. He used a computer to search for a solution: 33 = 8,866,128,975,287,5283 + (-8,778,405,442,862,239)3 + (-2,736,111,468,807,040)3

IMAGE SOURCE/GETTY

Mixed outlook for weather forecasts

Flash floods could become even less predictable than they are now

the two is shrinking. “This temperature difference is driving the weather in the mid-latitudes,” says Scher. Reducing that difference means a less frantic churn of weather systems. This explains why weather predictability didn’t change much in the southern hemisphere at the end of this century. Antarctica is only warming slowly, so the temperature gradient is changing less rapidly. The lower predictability of rainfall could cause problems

To cut down calculation time, the program eliminated certain combinations of numbers. “For instance, if x, y and z are all positive and large, then there’s no way that x3 + y3 + z3 is going to be a small number,” says Booker. Even so, it took 15 years of computer-processing time and three weeks of real time. For some numbers, turning up a solution is simple, but others involve

“It’s long been clear that there are maths problems that are easy to state, but fiendishly hard to solve”

for people who rely on knowing how much rain to expect over the coming week. Farmers and hydroelectric dam operators both need reliable information on this. The model suggests the biggest change will be in summer rainfall, says Ken Mylne at the UK Met Office. Because this is driven more by convection above hot ground, instead of large-scale weather systems, it tends to cause sudden and localised flash floods, rather than widespread and long-lasting floods. If summer rainfall becomes harder to predict, flash floods may take us by surprise even more than they do now. ■

huge strings of digits. “We know a solution for 30, but that wasn’t found until 1999, and the numbers were in the millions,” says Booker. Another example is for the number 3, which has two simple solutions: 13 + 13 + 13 and 43 + 43 + (-5)3, but we don’t know if there are others. There are certain numbers that we know definitely can’t be the sum of three cubes, including 4, 5, 13, 14 and infinitely many more. The solution to 74 was only found in 2016, which leaves 42 as the only number less than 100 without a possible solution. Donna Lu ■

THOMAS & PAT LEESON/SCIENCE PHOTO LIBRARY

IN BRIEF Species threatened by impact of people

Archaeology could dig up the ancient history of animals too TO MOST people, archaeology means the study of human

wear patterns on the anvil rocks and breaks the shells in a characteristic way, meaning shell waste left by these sea otters is distinct from that left by, say, people. This implies it should be possible to identify ancient sites where otters used rocks in this way, which could

history by uncovering traces of our past presence. But now it could be used to write the history of some animals.

reveal whether they have been using stone tools since they first evolved about 2 million years ago. This would

Natalie Uomini at the Max Planck Institute for the Science of Human History in Germany and her colleagues

involve the same techniques used for the study of ancient human sites (Scientific Reports, doi.org/c3kg).

are using archaeological techniques that could piece together the past of sea otters. They have analysed a site

The idea could extend to other animals, such as birds that drop hard food items on stones, fish that break open

at Bennett Slough Culverts in California where otters use rocks as “anvils” to get at mussels, rather than the usual

shells on rocks and monkeys that crack nuts on stones. “Archaeology can be applied to any species that

method of cracking them on a stone on their stomach. Uomini’s team has shown that this leaves distinctive

produces a durable material signature,” says Tomos Proffitt at University College London.

Time is up, space station germs KILLING microbes in a spaceship is surprisingly hard but that might be about to change. Bacterial biofilms, which can coat equipment and corrode it, have hit missions and can develop antibiotic resistance. But crew on the International Space Station can’t use aerosol cleaning agents, or liquids with flammable alcohol, so new fixes are needed. Now, an antimicrobial metal

surface that destroys bacteria on contact has been tested on the ISS, and may help keep astronauts healthy on future missions. Elisabeth Grohmann at Beuth University of Applied Sciences Berlin and her colleagues tried a metal coating called AGXX, made of layers of silver and ruthenium treated with vitamin C. The researchers fixed this and other metal sheets to the ISS’s

bathroom door. Taking swabs at six, 12, and 19 months, they found that, compared with sheets of stainless steel or silver, AGXX had a significantly reduced number of bacteria. By 19 months, there were 80 per cent fewer strains on the AGXX than on the steel (Frontiers in Microbiology, DOI: 10.3389/ fmicb.2019.00543). AGXX works by producing free radicals that damage bacterial cell membranes. “They really explode the bacteria,” says Grohmann.

ONE in four vulnerable vertebrate species are affected by humanmade threats to over 90 per cent of their habitat, and about 7 per cent are affected by human activity across their entire range. “These species will decline and possibly die out in the impacted parts of their habitat without conservation action. Completely impacted species will almost certainly face extinction,” says James Allan at the University of Queensland in Australia. Allan and his colleagues made the finding by mapping habitats of 5457 threatened terrestrial birds, mammals and amphibians around the world and determined the amount of human activity on them – such as farming and roads. They then analysed the sensitivity of each species to these. The countries worst affected were in South-East Asia, including Malaysia, Brunei and Singapore (PLoS Biology, doi.org/c3kj).

Many pills? One ring can deliver them all A COIL that sits in the stomach releasing medication over weeks could treat deadly tuberculosis infections and fight the problem of antimicrobial-resistant TB. The coil, developed by Malvika Verma of the Massachusetts Institute of Technology and her colleagues, is threaded with slowrelease pills. It can be unfurled to deliver it via the nose and throat to the stomach, where it springs back into a coil and stays put. The team tested it on pigs with antibiotics used to treat TB, with no apparent side effects (Science Translational Medicine, doi.org/ c3kb). People with TB need to take multiple tablets a day, but many find it hard to stick to the regime. This fuels the growing and deadly threat of antibiotic-resistant TB. 23 March 2019 | NewScientist | 19

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

IN BRIEF

A “SECRETIVE” new species of frog has been found in a forest in India’s Western Ghat mountain range. Dubbed the starry dwarf frog after the markings on its dark brown back, Astrobatrachus kurichiyana has an orange underbelly and is just 2 centimetres long. The frog, whose closest relatives are a group of species native to India and Sri Linka, is the only member of an ancient lineage dating back millions of years, according to researchers from India and the US. An expedition found the frog in leaves on the floor of a protected forest in 2010, as part of a wider project to look for new frogs, lizards and snakes. It was put in a specimen jar for later study. Genetic tests and a closer look at its shape, colour and other features show that it doesn’t match any existing species (PeerJ, doi.org/c3kh). Kartik Shanker of the Indian Institute of Science, says while it is common to find new frogs in India, this one was notable. The number of known species of frog identified in India has risen from around 200 to more than 400 over the past two decades. While many species new to science are frequently immediately classified as endangered, it is too early to say whether the starry dwarf frog is threatened. “They

SEENAPURAM PALANISWAMY VIJAYAKUMAR

are very secretive,” says Shanker.

20 | NewScientist | 23 March 2019

Dawn of the f-word: how farming reshaped the way we talk WHEN humans became farmers and sowed the seeds of modern civilisation, it turns out they were also reshaping spoken language. A ground-breaking study shows that diet-related changes in human teeth and jaws led to new speech sounds that are now found in half the world’s languages. More than 30 years ago, the linguist Charles Hockett noted that sounds called labiodentals, such as “f” and “v”, were more common in the languages of societies that ate softer foods. Now a team of researchers led by

Damián Blasi at the University of Zurich, Switzerland, has worked out how and why this trend arose. They found that the upper and lower incisors of ancient human adults were aligned, making it hard to produce labiodentals. Later, jaws changed to an overbite structure, making it easier to produce such sounds. The team showed this change correlated with the development of agriculture in the Neolithic period. Food became easier to chew, which led to changes in jaws and teeth: for instance, jaws that

don’t have to do as much work don’t need to grow as large. Analyses of a language database also confirmed there was a global change in world languages after the Neolithic, with the use of “f” and “v” rising dramatically in recent millennia. Today, these aren’t found in the speech of some hunter-gatherer societies (Science, doi.org/gfw2mg). The research overturns the prevailing view that all human speech sounds were present when Homo sapiens evolved around 300,000 years ago. BEN HORTON/GETTY

Newly discovered frog is a real star

Romeo and Juliet in a brain scanner IT IS often said that great actors lose themselves in their roles, and now a brain-activity study shows this is more than just a turn of phrase. While portraying a character, actors experience decreased activity in brain regions that help form a sense of self. To investigate, Steven Brown at McMaster University in Canada and his team got 15 trained actors to answer hypothetical questions, both from their own perspective and while assuming the persona of title characters in Shakespeare’s Romeo and Juliet. They also asked them to answer while pretending to be a real person they know well, in all cases while an MRI machine scanned their brains. Compared with responses from their own perspective, answering from a third-person point of view saw activity in the ventromedial prefrontal cortex fall, a part of the brain associated with regulating emotions, and the dorsomedial prefrontal cortex, associated with maintaining one’s sense of self. The changes were even stronger when in Shakespearean character, which Brown says indicates actors were suppressing their selfprocessing (Royal Society Open Science, doi.org/gfwwgk).

Nature’s wonders can be a bit random WATERFALLS are more spontaneous than we thought. It now seems some may arise without any clear influence from the surrounding terrain. Generally, we assume they form because of landscape features. For instance, an earthquake can create a cliff over which a river cascades, or it could simply flow over a patch of soft rock, eating its way down through it. But Joel Scheingross at the University of Nevada, Reno, and his colleagues found that a river flowing over smooth and homogeneous ground can develop waterfalls too. The team used a 7.3-metre-long

artificial riverbed made of polyurethane foam to simulate bedrock. They poured water and small pebbles into the top of this flume to make a miniature river with sediment flowing down it. The pebbles acted like tiny chisels, beginning to erode the foam riverbed almost immediately. Small differences in erosion caused a feedback effect, in which pebbles flowing into slightly deeper areas hit the bottoms of the pools harder and created even steeper drops. Eventually, some of these became waterfalls (Nature, doi.org/gfwwgz).

Where did we come from? How did it all begin?

And where does belly-button fluff come from? Find the answers in our latest book. On sale now. Introduction by Professor Stephen Hawking

INSIGHT ANTI-DRONE TECH

No-fly zone Drones near airports are grounding flights and leaving people miserable, but can we do anything about them? Chris Stokel-Walker reports

Drone sightings disrupted flights at Gatwick Airport last year 22 | NewScientist | 23 March 2019

of companies are selling antidrone technology – more than 155 firms in 33 nations, according to a report he produced. Around a third of these systems can both detect and attack drones, with the remainder roughly equally split between doing one or the other. Signal jamming is the most popular way to stop a drone in mid-flight: about 100 anti-drone systems on sale disrupt either the radio frequency (RF) link between

the drone and its operator, or the drone’s GPS connection, causing it to land in place or return to its take-off point. “In order to disrupt an RF signal, you transmit more energy on that frequency,” says Jonathan Aitken at the University of Sheffield, UK. “If it’s overpowered, you lose the link between the controller and the drone.” A defence system developed by UK-based Chess Dynamics uses

JEREMY SELWYN/EVENING STANDARD/EYEVINE

GATWICK. Heathrow. Newark. Franke, who studies drones Dubai. Dublin. In the past four at the European Council on months, airports have been Foreign Relations. brought to a standstill by the The US Department of Defense sight of drones hovering above is spending hundreds of millions runways. Last week, rules came of dollars on research and into force in the UK that make development for counter-drone it illegal to fly drones within systems, says Michel, while a slew 5 kilometres of an airport. But “These incidents expose is there anything more we can both the threat posed by do to stop them becoming a drones and the difficulty weaponised nuisance? The drone sightings all resulted in countering them” in the immediate grounding of flights due to fears that a collision could cause a commercial aircraft to crash. “These really high-profile incidents have brought to light not only the threat posed by drones, but the difficulty in countering them effectively,” says Arthur Holland Michel at the Center for the Study of the Drone at Bard College, New York. Most of the incidents lasted less than an hour. But given that flights at major airports take off or land so frequently – every 45 seconds at Heathrow in west London – even grounding planes for a short spell has considerable consequences. When passengers, crews and aircraft end up in the wrong place, it can take weeks to rectify. As a result, waiting for nuisance drone operators to get bored and fly off isn’t an option. Airports must be able to take active measures to prevent drones from ever reaching their airspace, or grounding them if they manage to slip through undetected. “Anti-drone technology is a massive growth area and countries around the world are interested in it,” says Ulrike

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Shoot them down RF jamming is not without issues, however. It would be incredibly disruptive in tourist hotspots, for example. “You don’t want to jam all Wi-Fi or mobile phone signals in a 1-kilometre radius around Buckingham Palace,” says Franke. Even at airports, it can cause problems. “We have sensitive equipment on an airfield,” says Aitken. “Putting a high-powered RF beam into that environment may damage other antennas.” GPS jamming is also not guaranteed to bring down a drone. After a series of drone attacks by Islamic State in Iraq in early 2017 (see box, below right), coalition forces asked drone manufacturer DJI to geofence the city of Mosul by updating the app used to control its drones, preventing GPS use and enforcing a no-fly zone. The terrorists simply switched off the GPS. While most autonomous drones rely on satellite navigation, skilled pilots can fly without the technology. Away from war zones, exasperated holiday-makers experiencing disruption often call for drones to just be shot down, but this isn’t really workable, especially in populated areas. “Drones are very cheap and air-defence systems are very expensive,” says Michel. Even bullets are dangerous, as anything fired into the air will eventually come down at lethal speed. This means such radical action

Send a drone to catch a drone, with a great big net

is only really acceptable in life-or-death situations. “There are many things you can do in a military environment that you can’t do in a civilian environment,” says Franke. Costs aside, the risk that a misfire could prove deadly meant the British police were loathe to shoot down the Gatwick and Heathrow drones either side of Christmas 2018. Then there are the more wacky ideas. Numerous police forces have tried and failed to train eagles to snatch drones out of the air, while police in Tokyo, Japan, have a squadron of interceptor drones that fire a net with an attached parachute that can take a target drone out of the sky. Similar technology was also used at the South Korean Winter Olympics in 2018. Before you even think about taking a drone out of the air, you need to find it. “There are lots of birds in the sky,” says Franke. “And birds aren’t that different from drones.” They’re both relatively small, travel slowly and existing radar systems

TOSHIFUMI KITAMURA/AFP/GETTY IMAGES

this method and was installed at Gatwick, near London, after its trouble with drones, reportedly at a cost of £1 million. And Ronald Reagan Washington National Airport near Washington DC jams RF signals in a 55-kilometre radius around its airspace. Portable jammers are also available. A gun developed by Australian firm DroneShield reportedly took down a drone at the 2018 Commonwealth Games held in that country.

aren’t calibrated to detect them. Opinions are split as to whether Cameras also struggle to discern anti-drone technology has a between drones that are close and bright future. “I’d like to come up aircraft that are far away. with an easy answer, saying there Still, new ideas for drone are lots of people researching it detection are being developed. and we’ve got one nice solution In the UK, Cranfield University is that’s going to fit, but there’s not working on a system that will use one,” says Aitken. 4G and 5G mobile connections “You don’t want to jam to provide real-time detection, all phone signals in a and is testing it on a private air 1-kilometre radius around corridor near the university’s Buckingham Palace” airport. However, there is little to stop those wanting to shake off detection simply disabling However, the sheer weight 4G and 5G capabilities on their of ongoing research means a drone before flying. solution is likely to come soon, says Franke. “A lot of different technologies are being developed, MALICIOUS DRONE USE and I think in the next few years we’re going to have some kind of In recent years, consumer drones have disrupted anti-drone technology installed airports and been used for weaponised attacks around airports, prisons and 25 February 2017 19-21 December 2018 other important areas.” In a video, Islamic State claims to have More than 140,000 passengers and She forecasts that portable carried out a drone-based attack in over 1000 flights are affected by technology – anti-drone rifles that Mosul, Iraq, by dropping a warhead drone sightings at Gatwick Airport, can direct an RF beam to overcome from an off-the-shelf drone – although near London. More than 100 sightings a single drone, for instance – will some experts say the footage appears were reported over three days, become more commonplace, to be fake. The terrorist group uses according to police, who believe an while systems that combine a similar method to destroy an arms airport employee may have been multiple methods of detecting depot in Syria the following October. behind the chaos. and stopping drones will become more popular and effective. 4 August 2018 21 February 2019 But it might take something Venezuelan president Nicolás Maduro In the latest incident of drone-based entirely new, says Michel. “People survives an assassination attempt disruption, flights are suspended are waiting for that silver bullet, while giving a speech in Caracas. Two at Dublin Airport in Ireland after that new paradigm,” he says. drones carrying explosives were used a “confirmed sighting of a drone”. “We’re hoping there’s a teenager in an apparent effort to kill him: one Travel into and out of the airport in a basement somewhere manages to hover close to Maduro and resumes after half an hour, but not concocting a new machine that’s detonate its payload, while the other before three flights are diverted to putting the final nail into the explodes two blocks away. nearby airports. coffin of drone attacks.” ■ 23 March 2019 | NewScientist | 23

COMMENT

One giant step for women The first women-only spacewalk is a cause for celebration, but we are still far from achieving equality in space, says Mika McKinnon

JOSIE FORD

OVER the past 20 years, 128 astronauts have spacewalked for a total of 1300 hours to assemble and maintain the International Space Station (ISS). Until now, just nine of those people have been women. Next week, when Anne McClain and Christina Koch step into the void, that number will rise to 11. Another milestone will be reached too: this will be the first of the 213 ISS spacewalks to be entirely composed of women. On the one hand, I am excited. On the other, I am trying not to wince. It is hard to be unreservedly enthusiastic when astronauts named Alex, Sergey, Stephen or Yuri spacewalk outside the station twice as often as women. Looking at the historical context doesn’t make this more cheery. Of more than 500 people who have reached space, just 64 have been women. Of 222 (soon

Charging forward With even James Bond making the switch, the electric car has come of age, says Jason Barlow WHAT would make you switch from a conventional car to a pure electric one? Its design? Its eco-credentials? Or an end to the accursed “range anxiety”? Whatever the reason, it seems the tipping point is finally here. Jaguar’s I-Pace recently became the first fully electric car to win the European Car of the Year 24 | NewScientist | 23 March 2019

is now redundant. You don’t need to be a member of Greenpeace to embrace an electric car. You don’t even need to be concerned about climate change. In 2019, the electric car has come of age. They are well designed and manufactured, they handle with the alacrity of their gas-guzzling equivalents, and of course emit zero emissions from the exhaust. Anxiety over their range and how the charging process works remain the biggest obstacles

award. Tesla, led by Elon Musk, has just unveiled its compact SUV, the Model Y. Now James Bond is swapping his internal-combustion Aston Martin for an electric model, the Rapide-E, a move apparently “You don’t need to be a inspired by the “tree-hugger” member of Greenpeace or credentials of Cary Fukunaga, concerned about climate director of the next film. to embrace an electric car” That rather tabloidy pejorative

to be 224) astronauts who have spacewalked, McClain and Koch are just the 13th and 14th women. Even the composition of this historic spacewalk is random chance, the outcome of Koch joining a rescheduled mission after a launch was aborted in October. Women are less likely to go into space at all, and if they do, they are half as likely to spacewalk. It isn’t physiological differences driving the divide. Astronaut Douglas Wheelock describes spacewalking as ballet on fingertips, meaning grip strength and mobility are more important than brute strength. But thanks to decades of studies that treated men as the default, we still don’t have a complete picture of how spaceflight affects women. Initial findings suggest that women may have greater resistance to the vision impairments that can

to uptake. But here too, the technology is at a crucial juncture, with Tesla leading the way. There are 12,000 Tesla superchargers across the US, Europe and Asia, with 99 per cent of the US population now covered. There are 360 bays in 50 UK locations, and Tesla is just rolling out its ultra-fast V3 supercharging tech. The company’s cars now also know when you are heading to a charging site and heat the battery to the optimum temperature for charging. Tesla says this cuts the average charge time by 25 per cent. Fully charged, most electric cars now have a range of about 500 kilometres.

For more opinion articles, visit newscientist.com/opinion

Mika McKinnon is a geophysicist and writer based in Vancouver, Canada

Meanwhile, Italian design legend Pininfarina has unveiled its first car, the Battista, which promises F1-levels of performance and a supercar look. Its electric architecture is licensed from a Croatian start-up, Rimac. The company’s founder Mate Rimac has the same irrepressible urge to change the world as Musk. “I wanted to make cars generally better and more exciting by electrifying them,” says Rimac. “I could see the potential and I couldn’t understand why no one else could.” Well, we do now. ■ Jason Barlow writes for BBC Top Gear and British GQ

ANALYSIS Air pollution

NURPHOTO VIA GETTY IMAGES

strike men in the astronaut corps, and their lower average size and metabolic rates may mean crews with more women consume fewer resources, but we don’t have enough data to know how much of that is down to individual variation. The future is slightly brighter, with the Australian Space Agency’s last two training cohorts being 50 per cent women, and the Canadian Space Agency doing likewise for its most recent recruitment. The European and Chinese space agencies aren’t keeping pace, however, and the Russian space agency doesn’t have a single woman in either its active or candidate astronaut corps. Change is coming, but it is still a long, slow slog to reaching gender equality, and diversity along other axes feels like even more of a fantasy. I will celebrate that we have two women spacewalking outside the ISS, and many more women running console support at Mission Control. But I am going to be swallowing my frustration during that victory toast, irate that we are only hitting basic markers of equality 50 years after humans first ventured into space. ■

Making sense of air pollution’s killing power Michael Le Page

out the damage done by air pollution is much harder than something like car accidents, for which we have firm figures, because it typically aggravates the effects of common disorders such as respiratory diseases. Many teams around the world have been doing long-running studies that compare, say, people living in areas with different levels of particulate pollution in the air to work out how it affects the risk of developing respiratory or cardiovascular diseases. The latest results suggest that air pollution is a far greater contributor to cardiovascular disease than previously

DOES air pollution really kill hundreds of thousands of people in Europe and 9 million worldwide every year? That is the apparent conclusion of a study claiming that air pollution causes 790,000 “extra” deaths in Europe each year, which is double previous estimates (European Heart Journal, doi.org/gfwtcd). However, the figures don’t mean that 9 million people dropped dead solely because of air pollution. Rather, they are a way of representing the harm done by air pollution. The study suggests that air “The figures don’t mean pollution is a bigger killer than that 9 million people smoking, which using the same dropped dead solely method is estimated to cause 7 million because of air pollution” extra deaths worldwide each year. “I think that’s the important message of this study,” says lead thought. But telling people their author Jos Lelieveld of the Max Planck “hazard ratios” for air pollution – the Institute for Chemistry in Mainz, standard scientific measure – would Germany. Air pollution has now mean nothing to most. joined the ranks of major risk factors Instead, it is standard practice to such as high blood pressure, diabetes translate risks into more meaningful and obesity, he says. measures. Lelieveld’s team combined It is important to understand where the latest risk estimates with data on these numbers come from. Working people’s exposure to air pollution in

Europe to work out the number of extra early deaths in 2015. “790,000 people died who would have died later if there was no air pollution,” he says. Of course, everyone dies sometime. Another way to express the same finding is that those 790,000 people lost 17 years of life on average, or that the average person in Europe loses two years of life because of air pollution. “These are just different ways of spreading the total days lost among different groups,” says David Spiegelhalter of the Winton Centre for Risk and Evidence Communication in the UK. “It’s a confusing area.” The situation isn’t especially bad in the UK. Air pollution causes 100 excess deaths in the UK each year, compared with 140 in Italy, 150 in Germany and more than 200 in eastern European countries such as Bulgaria, Croatia, Romania and Ukraine, according to the study. Air pollution has been gradually falling over the decades in Europe because of tighter controls on vehicle emissions – although in some places a rise in wood-burning is counteracting this trend. So air pollution contributed to far more deaths in the past – we just didn’t know about it. Only now are studies like this revealing its full impact. Ironically, this is partly because falling pollution levels mean we now have better data from less polluted areas, says Lelieveld. ■ 23 March 2019 | NewScientist | 25

APERTURE

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Moon juice THE spikes keep things quiet. Too much noise and the antenna pointing out the top couldn’t hear the signals it needs to peer through the frigid exteriors of Jupiter’s moons. This is a model of the Radar for Icy Moons Exploration (RIME) instrument. If all goes well, RIME will start studying Ganymede, Europa and Callisto in 2029 as part of the European Space Agency’s Jupiter Icy Moons Explorer mission, also called Juice. The scaled-down 1:18 model seen here sits in an anechoic chamber in the Netherlands for a test of a test: before Juice is launched in 2022, the full spacecraft will have to undergo similar checks to make sure we understand anything that might affect its performance in space. The real RIME antenna will be 16 metres long and use radar signals to penetrate 9 kilometres down, characterising the moons’ ice shells and maybe even reaching their underground oceans. These tiny worlds may be the best places in our solar system for life, so studying their frozen crusts and the hidden waters below may be key to our understanding of how life arises. Leah Crane

Photographer M. Cowan ESA

23 March 2019 | NewScientist | 27

COVER STORY

THE REALITY PARADOX The nonsensical result of a thought experiment may mean that quantum theory has a fatal flaw, says Richard Webb

ANTED: DEAD AND ALIVE! When it comes to Schrödinger’s cat, the hipster T-shirts write themselves. The zombie feline in an ambiguous state of animation fascinates the wider world. For quantum physicists, it is more of a tormentor, clawing at their belief in a treasured theory and coughing up hairballs over its claim to provide true enlightenment about the workings of reality. Scram, moggie. Schrödinger’s cat has just had an upgrade, and if you had a feeling the original was weird, it has nothing on the new one. Instead of placing a cat into an indeterminate state of dead-and-aliveness, a new scenario doing the rounds involves pulling off a similar trick with people who are themselves performing and observing a Schrödinger’s cat-type experiment. The reasoning is that if quantum theory is a universally valid theory capable of making

W

28 | NewScientist | 23 March 2019

sense of reality, it should be able to describe people using quantum theory. But this turns out to be a thought experiment in the best tradition of quantum bamboozlement. It blows up, providing a nonsensical answer that, taken at face value, removes our last tenuous handholds on the nature of quantum reality. Possibly. There is seemingly never any absolute certainty when it comes to quantum theory. But while some physicists continue to debate the true significance of the result, others see an opportunity in it, a clue to where a more powerful theory of the world’s fundamental workings might lie. Ever since its mathematical rules began to crystallise in the 1920s, quantum theory has been an affront to our sense of decency. In the world of things we can see and grasp, objects have robust properties that can be described by long-established, “classical” physical theories. In this realm, a cat has a binary

position on the dead-alive scale. It also has a definite weight, fur colour, whisker length, position in space. You can measure these things at any time you like without the expectation of ambiguity or sudden change (except maybe in position: cats do sometimes move in mysterious ways). In a word, classical reality is what we would call real. You wouldn’t labour this point if the quantum world wasn’t so different. Quantum theory characterises the workings of the stuff that makes up cats, us, everything, with peerless accuracy. Its predictions have never been found to be at odds with experiment. But it paints a distinctly peculiar picture of what lies beneath. An object that adheres to quantum rules doesn’t have a reality that can be pinned down. Its properties are encoded in a mathematical object known as a wave function that essentially says: if you make a measurement, here is what you might find.

“The measurement problem has sometimes been called the reality problem,” says theorist Lucien Hardy at the Perimeter Institute in Waterloo, Canada. “There’s a kind of mismatch between our understanding about the way the world is and the picture a naive interpretation of the quantum state gives us.”

TISHK BARZANJI

Shut up and calculate

Might – not will. Each time you measure a quantum object you “collapse” its wave function, causing the range of possible characteristics encoded in the maths to condense into a particular momentum or position, say. But measure an object prepared in an identical way, and you are likely to find different values for those properties. Only by repeating identical measurements can you gradually build up a sense of the object’s overall reality, according to the probabilities encoded in the wave function. So here’s a question: what is that quantum object doing before you measure it? Does it have all those properties simultaneously? Or none of them? And when you measured it, forcing it to adopt a definite guise, what actually happened? These conundrums lie at the heart of perhaps the most fundamental mystery in science, the quantum measurement problem.

“Before they are measured, the reality of quantum objects can’t be pinned down”

That word “interpretation” is crucial because from this point on, that is all we have: ideas or suppositions about what must be going on. The one with the fewest overheads is called the Copenhagen interpretation, devised in the Danish city by early luminaries of quantum physics in the late 1920s. A less august name for it is the “shut up and calculate” approach, because it essentially says that quantum theory isn’t a description of physical reality itself, but just an operational framework that allows us to make predictions about it. “It’s sort of a bit like a user interface,” says Hardy. Fed with the right inputs, it predicts outcomes of measurements – but that is all. What reality is doing before those measurements is simply not a question quantum theory deals with. Hardy himself isn’t a fan of that interpretation. “It makes it hard to tell a consistent story,” he says. Neither does it satisfy Nicolas Gisin at the University of Geneva in Switzerland. He knows his onions, having done pioneering experimental work exploiting quantum weirdness for real-world applications such as cryptography. “Practical physicists know what a measurement is, and they don’t have to care too much,” he says. “But if you want really to understand physics as providing a world view, you cannot accept that suddenly you have to say: forget everything, the measurement is just a kind of magical phenomenon that kind of comes on top of quantum and changes everything.” Such objections stretch way back. Albert Einstein pointedly asked if the anti-realism of the Copenhagen interpretation means the moon ceases to exist if we aren’t looking at it. But it was Erwin Schrödinger who in 1935 gave the objections their T-shirt slogan-level public profile, with his wilful, if mercifully hypothetical, act of pet-related violence. The scenario Schrödinger sketched was intended to illustrate the apparent absurdity of the interpretation. It places a flesh-andblood cat in a box with a vial of poison that can be smashed – sending the moggie to meet its maker – by a mechanism that depends on whether a radioactive atom decays or not. According to the Copenhagen > 23 March 2019 | NewScientist | 29

interpretation, the yes-or-no reality of this decay is undefined before you measure it. Ergo, so is the cat’s reality. It too is in a quantum superposition of being both dead and alive. This is a natural result of connecting the quantum and classical worlds. No theory dictates a boundary between them, and it is difficult to see where there could be one given that one world derives from the other. Quantum superposition states tend to be very delicate, which is one reason we have never put anything as large and lumpy as a cat in one. But we are working towards it. Real-world lab experiments have put ever-larger objects into quantum superpositions, even a tiny resonating metal strip visible to the naked eye. Not that your naked eye will ever see that superposition directly, because looking at something counts as measuring it. “As soon as you look at the cat, it will be either dead or alive,” says theorist Renato Renner at the Swiss Federal Institute of Technology in Zurich. “As it should be.”

“Until now, which interpretation of quantum theory you believed was a matter of just that – belief” Refinements of Schrödinger’s thought experiment have only deepened the mystery. In the 1960s, mathematician and physicist Eugene Wigner painted himself into the picture as an additional observer. As his friend conducts a Schrödinger’s cat experiment, Wigner stands outside the lab door. Before Wigner opens up and looks inside the lab, for him the friend-cat combination is in a quantum superposition of happy friend/live cat and sad friend/dead cat (presuming of course that Wigner’s friend is a cat person). This is so even if Wigner’s friend long ago opened the box and ascertained what state the cat is in, and by extension their own emotional

state. To compound the original measurement problem, quantum reality is now also observer-dependent. Different people can construe different versions of reality at any one time, with no way of saying which is right. To spare blushes, Wigner proposed that the first conscious observation always collapses the wave function. But this just raises further questions. “What is an observer?” says Gisin. “I am an observer, presumably. Schrödinger’s cat, maybe. Is a mosquito an observer? It’s just not precise.” Over the years, a panoply of rival interpretations has popped up to explain the problems away (see “Four ways to skin Schrödinger’s cat”, below). Gisin favours a class known as objective collapse. Renner was always part of the “many-worlds” crew. But with no way of experimentally probing them, which one you choose to believe in is a matter of just that – belief. For Renner, this wasn’t good enough. So he set out to break the deadlock with a more sophisticated thought experiment

Four ways to skin Schrödinger’s cat Many rival interpretations of quantum theory aim to avoid the problem highlighted by the Schrödinger’s cat thought experiment: a conscious measurement creating a definite reality. Here’s a selection The many-worlds

In objective-collapse

Bohmian mechanics

Quantum Bayesianism

interpretation says that

theory, wave-function

the probabilistic wave

collapse is either a thing

also restores certainty and determinism in the quantum

interprets the uncertainty of the wave function very

functions representing quantum objects such as

that happens naturally all the time, or it is something people

world by asserting new physics – and gives an

differently. Reality isn’t uncertain, you are. In the

particles or atoms are the real deal – not just mathematical

facilitate by fiddling about and measuring things, although

indication of what that might look like. In a hidden layer to

classical world, there is a lot you can’t know for definite

constructions, but the essence of reality. When you make a measurement, you don’t collapse many possibilities into a single reality, you merely peel off into a world that comes with that outcome encoded in it. The other outcomes persist in parallel worlds, together with versions of you that measured them – a bit like a choose-yourown-adventure story where you don’t get to choose your own adventure.

the exact physical mechanism is unknown. That solves the problem of observers creating reality, but it doesn’t tell you what reality looked like before collapse – and you still need to explain what physics is doing the collapsing.

reality, “pilot waves” connect and guide the fates of quantum particles, and it is our interaction with these that determine the nature of a measurement. But what are these waves?

without looking at it: for example, whether it is raining before you pull back the curtains. Before you do, you might assign a probability of it raining according to your past experience, before uncertainty collapses to certainty on observation. In the quantum world, you don’t create reality by measuring it any more than you make it rain by pulling back the curtains, you just update your state of certainty. In other words, try not to worry yourself about reality – it is all in your mind anyway.

30 | NewScientist | 23 March 2019

that he devised with his colleague Daniela Frauchiger, originally in 2016. It involves not one, but two Wigner’s friend-type arrangements. In the first, Alice waits outside a lab in which her friend is doing a quantum experiment, a kind of coin flip carried out using quantum technology whose outcomes, for the purposes of later maths, are weighted 2/3 one way and 1/3 the other. In parallel, Bob has his eye on a second lab where his friend is making a Schrödinger’s cat-type measurement (see “Having kittens”, right).

Having kittens Three generations of thought experiment have helped us explore what quantum theory says about the character of reality. The latest may create a paradox that can’t be explained away

Schrödinger’s cat

Alice

In Erwin Schrödinger’s original thought experiment, a quantum particle’s decay defines whether a cat lives or dies. Before Alice looks in the box, quantum theory appears to suggest the cat is both alive and dead. Many different interpretations of what this really means have sprung up

If the particle decays, a flask of poison breaks

A half open box The essential twist is that Alice and Bob’s friends’ labs – and with them Alice and Bob’s friends themselves – are in a kind of quantum superposition in which Bob’s friend’s measurement probabilities are determined by which way Alice’s friend’s biased coin flips. This means that when Alice and Bob perform a particular measurement on their respective friend’s lab, they can know for definite what happened with their friend’s experiment, but also have a clue as to what must have happened with the other friend’s experiment. “It’s a mixture between not completely opening the boxes but still comparing what’s inside,” says Renner. One after the other, the four agents perform their measurements. In analysing what happens, the thought experiment makes three basic assumptions about knowledge. First, the same theory of knowledge, in this case quantum theory, applies everywhere at all times. Second, measurements always have consistent outcomes everyone can agree on. Third, alternative facts aren’t allowed: if someone measures something, you can’t swear blind the opposite has happened. Such assumptions serve us well in similar problems of hidden information in the classical world (see “The muddy forehead problem”, page 32). But it turns out that in the quantum world they create a no go. Working through the mathematics shows that while on most occasions all observers end up in a consistent knowledge state, on average one time in 12 Alice and Bob see different realities when they open the lab doors. The Frauchiger-Renner paradox hits a level of weirdness that exceeds the previous feline thought experiments. Previously, there was a dead-and-alive cat that you never got to see, leaving room for doubt that it ever existed. In this experiment, all the measurements have been made and it is as if the dead-andalive cat is right there in front of you. There >

Wigner’s friend A later version painted in an extra observer. To Alice outside the lab, the cat’s state remains undefined even when Alice’s friend inside knows it for definite. Any interpretation of quantum theory must then also explain how observers can infer contradictory realities

Alice’s friend

Alice

The Frauchiger-Renner paradox In this more complex set-up, Alice and Bob sometimes observe different outcomes with their own eyes. Since no previous interpretation of quantum theory easily allows for multiple, really existing truths in the same universe, it suggests they are all lacking something

Alice’s friend

Bob’s friend Bob

Alice

Detector

Alice’s friend flips a coin and uses the result to set a property of a quantum particle

Bob’s friend measures that property, with the result linked to the cat’s survival

When Alice and Bob open their doors, they sometimes see conflicting results

23 March 2019 | NewScientist | 31

The muddy forehead problem IN THE world as we experience it, there are all sorts of scenarios in which information is hidden from us. But basic assumptions about knowledge and a little logical reasoning generally allow us to get around them. Take an old brain-teaser about two children who have been playing in the mud. A meddlesome parent tells them that at least one has mud on their forehead, and then asks both children repeatedly whether they can be sure if they have mud on their forehead. They obviously can’t see their own foreheads, but how many times must the parent ask before both children, assuming they are intelligent, responsive and have a sound grasp of logic, can answer “yes”? If you don’t want to know the score, look away now. There are two possible scenarios. First, if only one child is muddy, the first time the question is asked, one child can see that the other has no mud on their head, so knows

and can answer “yes”. Having heard this “yes”, the second time round the second child knows they must have no mud on their forehead, so can say “yes”. If, on the other hand, both children are muddy, the first time the question is asked neither child can say “yes”: seeing mud on the forehead of the other child doesn’t exclude the possibility that they too are muddy. But the second time round, the fact that neither said “yes” first time tells them both they have mud on their forehead, so both answer “yes”. Either way, it takes two rounds of asking for everyone to achieve a consistent picture. You can repeat the exercise with any number of children, and you always need to ask the question as many times as the number of children involved. The number isn’t so important though. The real point is that a consistent conclusion is always possible in the classical world. A recent thought experiment suggests this isn’t the case in the

they themselves must be muddy,

quantum realm (see main story).

is no single truth everyone involved in the measurements can agree on. “The resolutions of the old paradoxes of Schrödinger’s cat and Wigner’s friend don’t apply to this one,” says Renner. That disturbing conclusion is writ large in the title of the paper that, after many refinements, Frauchiger and Renner finally published in 2018: “Quantum mechanics cannot consistently describe the use of itself”. It isn’t yet possible to act out the thought experiment. We are a long way from having the technical know-how to connect quantum experiments in the way it requires. But it isn’t pie in the sky either. A related, if not as certainly damning, thought experiment has been carried out for real and the predictions of alternative facts stood up. Renner thinks that when quantum computers properly come to fruition, you might use them as the observers and so see how his scheme plays out for real. In the meantime, the claim that quantum 32 | NewScientist | 23 March 2019

“This time, it is as if the dead-and-alive cat is right there in front of you – there is no single truth”

theory can’t say which side of reality such an experiment will come down on is a weighty accusation. If the theory is the right way to explain reality’s basic workings, it must have universal validity. So it should be able to describe a complex system involving people who are themselves using quantum theory, in much the same way as classical physics can be used to describe people performing a classical measurement with tape measure and stopwatch, say. But it can’t. Apparently. Since the paradox was first circulated, there has been lively discussion of its significance. Some think the result plain wrong, and that there is a faulty or hidden assumption that renders the thought experiment invalid. Scott Aaronson, a computational theorist at the University of Texas at Austin, doesn’t count himself in that camp. He thinks the thought experiment represents a clever new scenario, but rejects the assumption that

quantum physics needs to be able to describe itself. “We already knew for a long time that quantum mechanics no longer really works in hypothetical scenarios where we ourselves are being manipulated as we try to make quantum-mechanical predictions,” he says. Sure, the theory doesn’t work when observers are themselves in a superposition. But we aren’t, so who cares? Hardy disagrees. “It is a significant theorem and it goes beyond the discussion we had before,” he says. “It’s undermining the absolute nature of truth – that is the problem here.” Of those who agree the paradox represents a new challenge, many think the resolution lies in loosening one of the three assumptions about the nature of knowledge that it relies on. At this price, one or other of the existing interpretations of quantum theory might provide a way out. Take Renner’s favoured many-worlds

TISHK BARZANJI

Why are the quantum and classical worlds so different? Physicist Vlatko Vedral will be speaking on this topic at New Scientist’s next live event, The Biggest Questions in Physics, in London on 6 April. newscientist.com/science-events

interpretation, which forgoes the part about alternative facts not being allowed – they are allowed, just in another universe. Renner initially thought this might work. But further investigation showed that there is no branch of the universe after the measurement where the answers of all four observers are consistent. “Before this thought experiment, I was relatively convinced that certain interpretations make sense,” says Renner. “Now I think none of them can.”

Alternative truth Gisin’s reading is that the first assumption about one consistent theory of knowledge is at fault, and that this favours his preferred interpretation, in which wave-function collapse is an objective feature of the universe. After a collapse, the rules of quantum theory cease to apply and the contradiction dissolves.

Others make similar claims for their favoured approaches. Loosen assumption two, for example, and you might allow a quantum Bayesianism approach, where all the uncertainty is in the eyes of the beholder. “Maybe what proves it really is something that has no clear solution is that people are not agreeing on what the solution might be,” says Renner. But this may just be opening the stable door after the horse has crashed out through the side wall. We already knew that quantum theory is starkly incompatible with general relativity, Einstein’s theory of gravity, which kicks in on very large scales. In most situations, the two theories don’t meet, but at the points where they do – at the event horizon of a black hole, for example, or the first instant of the big bang – unresolvable paradoxes crop up. Hypotheses that attempt to bridge the

divide tend to work on the assumption that general relativity is wrong, because quantum theory can explain all the other fundamental forces of nature. Now we might have a different perspective. “This experiment suggests that quantum mechanics itself runs into problems when we go to large systems, without even talking about relativity,” says Renner. Hardy agrees that further enlightenment lies in the search for ways to unite quantum theory and relativity – and that the discovery that quantum theory makes incontrovertibly contradictory statements for different observers under certain circumstances provides a valuable starting point. He sees the situation as analogous to when general relativity replaced Newton’s earlier theory of gravity. Like quantum theory, Newtonian gravity was a good operational framework – you plugged in the numbers and it gave the right answers. But it didn’t give any physical picture of how gravity actually worked. It was only following up on the tiny instances where Newton’s theory got it wrong that led Einstein to his richer, physical picture of how the warping of space-time creates gravity. “The resolution of the problem didn’t come from any existing way of thinking, but from something entirely different,” says Hardy. Hardy’s suggestion of where to look for a more powerful theory lies in borrowing ideas from relativity: ideas about different frames of reference and how they interrelate. “It seems like that might be the right mathematical framework to describe how to go between these different classical worlds,” he says. But what such a theory might look like is a huge work in progress. If it requires new, undiscovered physics, it might end up looking like an objective collapse model of the sort Gisin favours, Hardy speculates, with gravity having some part in the collapse mechanism. “But, of course, I don’t know.” Renner and his colleagues are busy working to convince the doubters by programming a classical computer to simulate quantum computers acting as the observers, to at least prove that the reasoning of the thought experiment is sound. “I don’t expect any surprise,” he says. “The simulator will just show that there is a contradiction.” If so, the quantum cat really is among the pigeons. ■ Richard Webb is New Scientist’s executive editor 23 March 2019 | NewScientist | 33

THE GOLDILOCKS PLANET

KACPER KOWALSKI/PANOS PICTURES

Could an unorthodox form of evolution have made Earth just right for life, wonders Bob Holmes

34 | NewScientist | 23 March 2019

N 1948, cybernetics pioneer Ross Ashby built a curious machine. The Homeostat was constructed from four interconnected bomb-control units scavenged from the UK’s Royal Air Force. It featured four pivoting magnets, the position of each being determined by that of the others and guided by feedback mechanisms generated using a table of random settings. When Ashby turned the machine on, the magnets would start to oscillate wildly. Sometimes they would return to a stable equilibrium position. If not, Ashby

I

had wired the Homeostat to reboot itself with a new selection of random settings. Over time, this basic algorithm – if unstable, try again – always eventually led to equilibrium. That was the machine’s sole purpose: to show that a simple, dynamic system would regain stability in response to changes in its environment. Ashby believed this “ultrastability” to be a governing principle in nature, explaining, among other things, the adaptation of species to their niche – a process that appears purposeful, but actually arises from random

For millions of years, Earth has provided water, oxygen and the key elements required by life

processes. It may seem a stretch to describe the Homeostat’s change over time, from wild motion to stability, as “evolution”. After all, it lacks all the trappings we associate with Darwinian evolution – such as life and reproduction. Yet, there is a growing belief that the same forces driving Ashby’s machine hold the key to a wider concept of evolution, one that can encompass semi-living and even nonliving systems. This new view may prove essential to understanding the functioning of ecosystems and even the origin of life. Most intriguingly, it bolsters the Gaia hypothesis, the controversial idea that the biosphere acts like a giant organism, one that self-regulates to keep conditions just right for life. Darwin’s original formula for evolution by natural selection works as follows: organisms vary, those with more favourable traits leave more offspring on average and these offspring are likely to inherit their parents’ favourable traits. This explains why organisms are well adapted to their environments – why seedeating birds have thick, strong bills, why flowers produce sugar-rich nectar to attract pollinators, and countless other traits. As our evolutionary thinking has developed, natural selection has proved remarkably adaptable. It can explain the evolution of “selfish genes” – an idea popularised by biologist Richard Dawkins in the 1970s – because, like individuals of the same species, a gene may exist in various forms, some of which are more likely to survive and be passed on to future generations. Under the right circumstances, natural selection can even extend to discrete groups of organisms, as when more cooperative populations do better against less collaborative ones. However, this Darwinian dynamic breaks down at the level of Gaia, the whole planet. As far as we know, Earth is a one-off: there is no population of competing, reproducing planets for natural selection to choose between to form the next generation. And yet, like a superorganism honed by evolution, Earth seems to self-regulate in ways that are essential for life. Oxygen levels have remained relatively constant for hundreds of millions of

years, as has the availability of key building blocks of life such as carbon, nitrogen and phosphorus. Crucially, Earth’s surface temperature has remained within the narrow range that allows liquid water to exist. It is true there have been upheavals: during a “snowball Earth” episode about 700 million years ago, for example, almost the entire surface was frozen. “But the key question is, why does it spend so much time in a stable state and not just flying all over the place?” asks Tim Lenton at the University of Exeter, UK. This question has stumped earth scientists since James Lovelock first proposed the Gaia hypothesis in the 1960s. There is, after all, no obvious way for such self-regulation to evolve. This is particularly true because the processes that underpin Earth’s temperature, oxygen levels and the like – which include things like plate tectonics and erosion – operate over millions of years. That is far too long for the adaptation of individual organisms to their environments through natural selection to make a difference. This conundrum has led most evolutionary biologists to entirely reject any notion of Gaian evolution.

“Like a superorganism honed by evolution, Earth seems to self-regulate” “You simply cannot get an adaptation at the planetary level,” says Charles Goodnight at the University of Vermont. But there might be another way, says Lenton. What if Gaia works like Ashby’s Homeostat? In other words, he suggests, Earth and the early life on it might have interacted haphazardly at first. Unstable configurations – those, say, with little or no cycling of key elements such as nitrogen – would have failed quickly, requiring life to reboot nearly from scratch. Eventually, though, the system must have stumbled on a stable configuration, with better cycling and tighter regulatory mechanisms. It should be no surprise, then, that the planet of today has strong regulatory systems. > 23 March 2019 | NewScientist | 35

This process, called “selection by persistence”, evades the requirements for competition and reproduction that make natural selection so problematic as a mechanism for explaining the evolution of Earth. “I think of it like a search algorithm,” says Lenton. “[Earth] can undergo repeated trials over time until it falls into a stable configuration. And once it does, that tends to persist.” The process doesn’t stop there either, according to Lenton. Once the system is in a stable state, it can accumulate further changes – new regulatory mechanisms, for instance – that stabilise it still further. He calls this “sequential selection”. As a result, stable systems not only persist, they get better at persisting over time too. In research published last year, he and others describe how this gradual improvement adds up to an evolutionary process that could lead to Gaian self-regulation. Lovelock, for one, is enthusiastic about the idea. “The problem with Gaia and other dynamic feedback systems is that they can be described but

cannot be explained,” he says. “Lenton and his colleagues have extended the Gaia theory.” However, although selection by persistence may make perfect logical sense, is it feasible in practice? Self-regulation arises easily in relatively simple systems, as Ashby’s Homeostat illustrates. But as systems become more complex, the number of possible states they can have rises dramatically – and the

“Stable systems don’t just persist, they get better at persisting over time” odds of randomly stumbling on a stable one go down just as steeply, says Alexandra Penn, a complexity scientist and evolutionary theorist at the University of Surrey, UK. “Is it plausible within the lifespan of the Earth that we would end up there?” she wonders. As far as she knows, no one has answered this. Sceptics also question the claim that systems should become more robust over

Things can only get better Living systems, including Earth’s biosphere, could evolve and become better adapted via a variety of processes depending on their size and the timescale involved

Observer self-selection A version of the “anthropic principle” whereby the universe must be capable of evolving conscious life because we observe it

1026

1021 Selection by persistence The process by which a system evolves because more stable states last longer than less stable ones

Spatial scale (metres)

107 Sequential selection The method by which a stable system accumulates further changes that make it even more stable

6

10

105 Niche construction The process by which organisms influence their own evolution by altering their environment

4

10

103

Group selection 102

The means by which well-adapted groups are more likely to survive than their less well-adapted competitors

10

Individual selection 1

Regular Darwinian evolution occurring as a result of survival of the fittest

10-3

1

103 106 Timescale (years)

36 | NewScientist | 23 March 2019

109

SOURCE: doi.org/gd3qcm

time by accumulating stabilising changes. “The longer you’re in a system, the more time you can destabilise it, too,” says Daniel Schrag, a geochemist at Harvard University. That’s true, Lenton concedes. But his mathematical models, described in a recent paper, suggest that the stabilising effect outweighs the destabilising one in the long run. There are other reasons to expect stability to increase over time. If a system is to persist rather than collapse in the face of change, it needs to be robust. Three features make an ecosystem, or a planetary system, more robust, says ecologist Simon Levin at Princeton University. First, robust systems have some degree of redundancy, so the loss of any particular component – the extinction of a species, say – doesn’t critically compromise the whole. Second, they have diversity, which increases the odds that at least some species will be able to cope with unexpected changes. Third, they have modularity, so that a failure of part of the system doesn’t bring down the whole thing. The longer a system evolves, the more likely it is to show all three of these features, says Levin. In other words, robustness increases over time. Earth’s biosphere has been around since the first life evolved more than 3.9 billion years ago, so it has had plenty of time to become more robust.

Planetary reboot Although mathematical models can show that selection by persistence is possible, they cannot demonstrate that it actually happened on Earth. However, Lenton sees several ways to test his hypothesis. “Isn’t Earth history a test case of these ideas?” he asks. In particular, we know the planet has gone through several catastrophic transitions that swept away the old biosphere and forced the few surviving life forms to create a new one. Prime among these transitions would have been the so-called great oxygenation event about 2.4 billion years ago, when oxygen levels in the atmosphere rose dramatically from near zero after the evolution of photosynthesis. The appearance of highly reactive oxygen would have upset all the existing biogeochemical cycles and the metabolisms of organisms dependent on them. If Lenton is right, this would have triggered a period of planetary instability followed by the gradual emergence of a new, increasingly stable Earth system as the biosphere accumulated fresh metabolic pathways to regulate its novel regime.

KACPER KOWALSKI/PANOS PICTURES

Earth maintains its temperature within the narrow band that’s just right for liquid water to exist

There are no organisms from that long-ago time, but by working back down the tree of life, biologists are starting to figure out when particular metabolic innovations emerged. “If we’re lucky, we’ll be able to piece together how the origin of new metabolisms disrupted the status quo,” says Lenton. “We’ll be able to test whether, when we get a more stable version of something like the nitrogen cycle, it displaces an earlier, less stable version.” Looking at our own planet’s history isn’t the only way to assess the idea. The strongest test could come from life on other planets. How often does extraterrestrial life appear, and how long does it last? Are there millions of planets where life appeared but failed to self-regulate, suggesting a “Gaian bottleneck” that Earth was lucky to squeeze through? Or is selection by persistence ubiquitous, inevitably driving planetary processes towards stability wherever life arises? Given the lack of success in our search for life elsewhere in the universe, answers to such questions are a long way off. But perhaps we needn’t go to such lengths. A change of perspective could be all that’s required, argues Frédéric Bouchard at the University of Montreal, a philosopher of science who researches the theoretical basis of evolution. He believes our habitual focus on reproduction as the way to measure fitness has blinded us to other possibilities. “It’s as if

you had only seen mammals,” he says. “You’d infer that all species need legs. Then I show you a fern and you say it’s not an organism because it doesn’t have legs.” From Bouchard’s perspective, natural selection favours traits that enhance persistence, with reproductive success being one way to do that, but not the only one. Consider, for example, one of the world’s oldest and largest organisms, a grove of quaking aspen trees in Utah that all sprout from a single interconnected root system. Although individual trunks come and go,

“The strongest test of this idea could come from life on other planets” the grove has been a consistent genetic entity for an estimated 80,000 years. It may reproduce sexually now and then, but it makes more sense to think of its success in terms of persistence, says Bouchard. In fact, selection by persistence may be just one of a variety of selection mechanisms involved in evolution (see “Things can only get better”, left). And, since persistence really comes into its own in bigger systems and on longer timescales, it may be important for much more than just Gaia.

Consider ecosystems, such as a coral reef or the collections of microbes in your digestive tract. Ecosystems may compete against each other, but they do not reproduce as a whole. Yet they do, arguably, have traits that call for an evolutionary explanation. Like Gaia, they are often self-regulating, maintaining relatively consistent functions, even as their component species come and go. For example, a study of the green seaweed Ulva australis revealed that the microbial ecosystems living on any two algae had, on average, just 15 per cent of species in common. Nevertheless, they shared 70 per cent of their ecological functions such as attachment, defence and biofilm formation. This consistency is hard to explain by selection acting on individual species, because no microbe performs all roles. But it fits the notion that selection by persistence has shaped the ecosystem. “Even if you’re selecting only for persistence, you can get better and better,” says evolutionary biologist Ford Doolittle at Dalhousie University in Canada, who was one of the first to consider the role of persistence in evolution. Such examples are common, he adds. Lenton believes his unorthodox form of evolution might be the best way to understand social and cultural evolution, too. After all, cultural knowledge doesn’t exactly reproduce. Instead, concepts gain in influence by spreading, a dynamic that may be better described using selection by persistence than by conventional evolution via natural selection. Lenton is now exploring how this might work and whether it can give us fresh insights into cultural evolution. Lenton’s novel evolutionary mechanism might even shed light on life’s biggest mystery. Back before the first living cell evolved, the primordial soup probably consisted of various molecules that collectively managed to create more molecules somewhat, but not exactly, like themselves. In such a system, success would have constituted the continued survival of a loose collection of molecules. In other words, says Bouchard, persistence rather than reproduction was the driving force behind the origins of life. Selection by persistence could explain a lot about the world. The question is whether the idea itself will persist. Like Ashby’s Homeostat, it may require a reboot. But, in a pleasing circularity, if Lenton’s theory proves plausible and reaches a stable equilibrium, then it should accumulate further changes that will make it even more persistent. ■ Bob Holmes is a writer based in Edmonton, Canada 23 March 2019 | NewScientist | 37

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Super-sized income Gobbling food online can be lucrative – especially if you point the camera at your child, finds Amelia Tait

ZHANG QICHEN/VCG VIA GETTY IMAGES, JEROME GENCE, MICHAEL RICHTER/GETTY, BAFANA FAMILY, CANDOO FAMILY, CHEAP LAZY VEGAN/THECHEAPLAZYVEGAN.COM, PARK SEO-YEON, YE KWON TV

38 | NewScientist | 23 March 2019

IKE many 2-year-olds, the youngest member of the Candoo family loves fast food. Unlike most 2-year-olds, her parents earn money whenever she eats it. For over half her life, she has been delighting her family’s 370,000 fans by eating in front of a camera. More than 4 million people have watched a video of her enjoying chicken nuggets and fries, while nearly 3 million have viewed her 6-year-old brother devouring a burger. The Candoos are a family of YouTubers. Parents Katherine and Andrew broadcast themselves and their five children eating fried chicken, tacos, burgers, instant noodles and pizza on their channel Eating with the Candoos. The US family, and others like them, earn money from adverts that play before their videos and take direct sponsorship from companies, most recently a video for food subscription service HelloFresh. Overall, it is pretty simple: they eat, they film themselves, they make money. But why are their videos so popular? And is there a physical and psychological toll on their children? Originating in South Korea in 2009, a mukbang – Korean for “eating broadcast” – is a video of someone eating large quantities of food. Its pioneers were adults. By 2015, some of the most popular South Korean mukbang creators were reported to earn up to $10,000 a

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month live-streaming themselves. Academics began theorising about why people enjoy the videos: a study by Hye Jin Kim at Chosun University in South Korea posited that they relieve stress. In 2016, US journalist and cultural commentator Jeff Yang claimed the videos enabled lonely, unmarried South Koreans to simulate social eating. Then, last year, the genre took off on YouTube, earning it a place in the website’s official yearly recap, YouTube Rewind. According to video marketing company Tubular Insights, mukbang YouTube videos grew from generating 85 million views in October 2017 to 128 million views by April 2018. The rise can partly be attributed to 30-year-old Shane Dawson – a popular YouTuber in the US with 20 million subscribers – who filmed a viral 10,000-calorie mukbang with his friend in January 2018. Dawson brought the genre to a brand new audience, and other Western YouTubers quickly capitalised on its popularity. “We saw that it was quite trendy on YouTube and people seem to enjoy that type of content, so we thought we would try it,” says Londoner Nikky Bafana, a full-time family vlogger who filmed her 6-year-old daughter doing a Pizza Hut mukbang in August 2018. The previous month, the Candoos went viral after their

2-year-old ate spicy noodles with one of her sisters, and a new appetite for child-centric mukbangs was born. “It’s this whole big thing that’s on YouTube now. It’s not just adults that can do it, kids can do it too,” says Nikki Ean, a US woman who earns up to $2000 a month from her 6-year-old daughter’s mukbangs. Ean says her daughter’s subscribers increased “a whole lot” after the 6-year-old began eating in front of

“Some watch just to decry the perceived manipulation of the children” the camera. She has now eaten everything from king crab legs to McDonald’s Big Mac meals in more than 30 mukbang videos. The draw of the videos, especially those featuring children, might seem baffling to many. Their appeal in the West could be tied to the rise of “dude food” TV in the 90s, when food shows began to focus less on cooking and more on eating, says Glen Donnar at RMIT University in Melbourne, who studies mukbangs. People like to watch to gain an intimate and visceral experience. In general, family vloggers are popular because they

trade on making the ordinary and everyday visible, says Donnar. “It seems adults watch for a mix of positive or negative reasons: either because they think the kids are cute or the family dynamic sweet, or because they want to loudly decry the perceived manipulation of the children, the parents’ commodification of their children’s image, and food choices deemed extremely unhealthy,” says Donnar. Child mukbangs are now a global phenomenon. In Canada, a mukbang star with 1.8 million subscribers frequently films with her children, while in Japan, two young siblings broadcast their homemade meals to 400,000 subscribers. In the UK, a dad and his three daughters chat over KFC and McDonald’s; in Pakistan, two primary school-aged brothers do timed challenges. “Eating together should be a family time to bond and share, but it’s being used as a spectator sport, which is a sad reflection of modern society,” says Aisling Pigott, a spokesperson for the British Dietetic Association and a registered dietician. Pigott worries about how these videos may affect young viewers. “We know early years’ nutrition sets little ones up for life – both in terms of physical risk and emotional relationship with food,” she says. > 23 March 2019 | NewScientist | 39

Junk food tube? While fast food giants rarely pay Western mukbangers to promote their products, one concern is that the videos may undermine efforts to curb children’s exposure to adverts for unhealthy foods. Since 2007, the UK has prohibited advertising foods high in fat, sugar or salt before, during and after children’s TV shows. But children are still exposed to these unhealthy foods online, says Anna Taylor, executive director of UK think tank the Food Foundation. And, of course, many mukbang videos include packaging branded for the fastfood outlets where the items were purchased. Bahee Van de Bor, a specialist paediatric dietitian in London, also notes the potential psychological consequences of being a mukbang star. “If a child is only being filmed when they’re eating these high-fat, takeaway foods, then they may associate these foods as being very positive, when in fact there are nutritionally better choices,” she says. Internet stardom could also be damaging for children, who face scrutiny and comments from thousands of viewers. Larry Jones, a US man who broadcasts mukbangs with his wife to 65,000 subscribers, recently decided to stop filming his daughter. “I felt we were exploiting our daughter. I didn’t want to put her on screen just for the sake of views, just for the sake of monetary gain,” he says. “It really messed with my integrity.” 40 | NewScientist | 23 March 2019

Child mukbang videos feature kids eating a range of foods – from Big Macs to sushi

Skip Ad When he began to video his daughter, Jones says his views “skyrocketed” – some months the family earned $3000 from their videos. But commenters also critiqued his daughter’s speech patterns when she was just 3 and other blogs insulted his parenting skills. Three days after being asked for comment on child mukbangs for this article, YouTube began removing Eating with the Candoos videos, notably those featuring the family’s 2-year-old. The Candoos have uploaded mukbangs of their children for three years. “We believe technology presents great opportunities for young people to express themselves creatively and access useful information, but we also know we have a responsibility to protect young creators and families, and consider the potential impact of emerging trends on them,” said a YouTube spokesperson.“We have seen interest in young creators making mukbang videos, so we’ve been working with experts to update our enforcement guidelines for reviewers to remove videos featuring minors engaged in more intimate or inappropriate acts.” Restrictions are also on the way in the nation where it all began. In July 2018, the South Korean government launched a strategy to tackle obesity after national rates rose from 26 per cent in 1998 to 34.8 per cent in 2016. Part of this was a pledge to create guidelines for mukbang videos. Yet no child mentioned in this article appears obese and videoing kids eating isn’t inherently wrong. Ean dislikes mukbangs with excessive quantities of food, and her 6-year-

“Some months the family earned $3000 from their daughter’s videos”

old daughter has eaten scallops, squid and sushi on camera. This might inspire other children to have a more varied diet, she says. “The more open you are at a young age, the more open you’re going to be as an adult.” Bafana – who only has a couple of mukbangs on her channel, but plans to do more – says viewers also misunderstand her 6-year-old’s relationship with YouTube. “People don’t realise that she wanted to start YouTube and she enjoys it. I’ve always said that if she comes to me and says she no longer wants to be in the vlogs, that’s perfectly fine with us.” While the Candoos didn’t respond to a request for comment, they have responded to criticism in previous videos. In November 2017, Andrew mocked concerned fans. In a falsetto voice, he imitated internet commenters: “Oh my god, I can’t believe you guys are giving a baby hot Cheetos” before adding, “Sorry, not your child.” Although the issue is complicated, it is clear the area is presently under-regulated. The Candoos also allow viewers to request certain meals in exchange for money sent via PayPal – a set-up that seems open to abuse. Shortly after YouTube took down some of their videos, the family uploaded another showing their 10-year-old daughter eating cheesy fries. “This video most likely will be removed by YouTube like most of our other videos. So I wont [sic] be posting after this one,” the description reads. Since then, they have uploaded videos of their older children eating McDonald’s, chicken wings and seafood – and their 2-year-old eating an array of sweets. The Candoos don’t seem to be going anywhere. And there will probably be no shortage of copycat YouTubers after a piece of the pie. Q Amelia Tait is a freelance journalist based in London

MICHAEL RICHTER/GETTY

One 2018 study from the University of Liverpool, UK, split children into two groups and showed them famous YouTubers eating healthy or unhealthy snacks. The children were then offered food. Those who saw the vloggers eating fatty foods ate 26 per cent more calories than those who didn’t. The demographics of a YouTuber’s audience aren’t available to the public, but a quick glance at the Candoos’s social media pages shows that many of their fans are young children. “I don’t watch kid mukbangs when I’m alone, only when my kids are watching, just because I know it will be something appropriate for them,” says Kissondra Giordano, a mother in the US, who recently made a mukbang with her children. Over half of the UK’s 3 to 4-year-olds and more than eight in 10 of its 5 to 15-year-olds now watch YouTube. The popularity of the mukbang videos among children is understandable, says Donnar. “Kids love watching other kids and they love reliving or encountering treasured or special experiences and moments from their own life.”

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CULTURE

The new capitalism that remakes minds We are living in a time of unprecedented surveillance that is dramatically reshaping our world – and us, says Shoshana Zuboff in a new book. She talks to Pat Kane empowering and democratising. Instead, it’s an actual challenge to democracy, a controlling power.” Surveillance capitalism, as typified by Google, Facebook and Twitter, makes profits by seducing us onto various platforms, and monitoring our behaviour. That

The Age of Surveillance Capitalism: The fight for a human future at the new frontier of power by Shoshana Zuboff, Profile Books

JASON PAIGE SMITH/GUARDIAN/EYEVINE

SINCE the financial crash of 2008, and during the decade of austerity and “This relentless new form upheaval that of capitalism will stop at followed, the nothing to gather data search has been on all human behaviour” on for a new Karl Marx, a thinker who can see our current system, and its crises of information is sold to advertisers, money, technology and work, as who target us ever more precisely a vast and interconnected whole. with products and services. This I am not sure that a measured much we think we know. business professor from Harvard But Zuboff’s challenge to this University called Shoshana thinking is deep – and threefold. Zuboff would want to be seen First, she wants to alert us to how as a modern version of the relentless this form of capitalism polemicist of poster or biopic is. Industrial capitalism works by fame. But she might not mind generating surpluses. Zuboff’s being the author of a book that surveillance capitalism, however, many would hand to Marx as an essential catch-up, should he unaccountably reincarnate some 130 years after his death. Her book is called The Age of Surveillance Capitalism, and over nearly 700 pages it painstakingly outlines the economic form we are living under, mostly in the West, but increasingly globally. Sitting with a coffee and a cake in London, Zuboff muses on how she decided on her title. “The way that we are an information society is completely different from what we imagined when the internet first presented itself and we thought it was going to be 42 | NewScientist | 23 March 2019

generates its surpluses from human behaviour, public and private, and the more it understands about us the better it can sell its predictions about our desires and next moves. This surplus was created accidentally, but has now become a secret resource – as much about subtle coercion as about making money. Second, she emphasises that it doesn’t need to be this way. When “aware homes” were first mooted in 2000, it was assumed that the data they gathered on health, fitness, security and the like would be in a “closed loop” under the control of the people generating that data, says Zuboff. Fast forward to 2017, when two academics at the University of London analysed a thermostat made by Nest, by then part of the empire that included Google. Nest’s apps can gather data from other connected devices, including cars, ovens and beds. To keep the data private and stop the predictions made from it being sold on by Google to third parties, the researchers concluded that a consumer would have to study a minimum of 1000 privacy, end-user and terms-of-service contracts. The original, single closed loop of the aware home would never keep informationhungry firms like Google at bay. Originally, Google’s founders weren’t keen to rely on advertising for income, knowing that it would corrupt the search process, she says. But in 2001, the dot-com

Can we create an unmonitored sanctuary where we can be free, asks Shoshana Zuboff (below left)

financial crisis in Silicon Valley pushed some in the industry in a wholly new direction, towards something that could only be successful if done secretly: surveillance’s one-way mirror. That secrecy undermined human rights, which is Zuboff’s third passion. She is determined to alert us to the need to assert those rights against this slippery, pervasive new regime. But when it seems so natural to communicate with friends and family via our digital devices, what could shock us out of our complacency? Perhaps a close inspection of the words Zuboff has coined and the power structures she has defined. Let us start with “instrumented”. For her, this describes an ever-growing list of ways our freedom to act is being measured out of existence. Zuboff quotes the case of

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Spireon, a “connected vehicle all manner of technosurveillance intelligence company” that can to reward and punish its citizens, remotely switch off the engines of while the Western version seems to vehicles, based on its monitoring be heading in the same direction. of how poorly the driver Towards the end of the book, performed on previous drives. Zuboff lays the blame for this at It can measure if their eyes are the feet of some of Silicon Valley’s on the road or looking at friends. odder cultural assumptions. We are in a strange world, “Inside these organisations, where familiar politics are upside there’s a milieu of absolutism and down. In place of totalitarianism, intense hierarchy,” she says. “They there is another coinage, determine the standards. They “instrumentarianism”. She uses “It kills me that the only way this word to describe the logic my children will experience of, and power that comes from, sanctuary is by hiding from recording and anticipating an unimpeded power” human behaviour, when the elites of surveillance capitalism quietly harvest the raw material translate the greater good into of human actions and steadily behavioural requirements. I refer shape our sense of the future to them as a priesthood. They without us realising it. have a conceit that goes with their The weird thing, Zuboff writes in unique knowledge. For them, her book, is how this is beginning computation replaces politics.” to unite the political cultures of And there’s the rub. How can East and West, of democracy, we possibly resist this Matrix of dictatorship and one-party states. subtle prediction and control? Especially when it might prove We tut at China’s Social Credit to be the ultimate form of System, which lets the state use

capitalism, with the power to reshape humans as never before? In the book, she warns that as industrial capitalism flourished at the expense of nature and now threatens to cost us the Earth, so “an information civilization shaped by surveillance capitalism and its new instrumentarian power will thrive at the expense of human nature and will threaten to cost us our humanity”. She ends her book with a plea for the importance of her version of “sanctuary”, a free and unmonitored zone where all humans feel they can “shape their intentions as they see fit”. A place that is anathema to the modern merchants of surveillance and prediction. How is this sanctuary created? Drawing directly from Marx, Zuboff goes back to the trade unionists and reformers who moderated the harsh edges of 19th and 20th-century industrial capitalism. But she still believes that “the marriage of democracy and the market can again produce relatively stable and prosperous and inclusive forms of living”. Recently, she has been asking Apple – whose business model is much less focused on surveillance than that of its competitors – to forge “an alternative path towards the digital future, reuniting capitalism with the people it should serve”. And she respects renegades like Edward Snowden who want to protect our digital activity from the gaze of states or corporations. “Encryption may be an option – if democracy fails us,” she says. But you can tell how worried Zuboff really is by the way she ends our interview. “It kills me to think the only way my children will experience sanctuary – when you clear a space for the experience of your own will – is by hiding from an unimpeded power. The idea that we have to hide in our own lives is intolerable.” ■

Visit Timed to mark the 500th anniversary of the death of Leonardo da Vinci, Thinking 3D: From Leonardo to the Present opens at the University of Oxford’s Weston Library on 21 March. Explore 500 years of experiments in bringing flat surfaces to solid life.

Play On 22 March, game developers PQube release Our World Is Ended. This engaging digital novel promises to trap you between real and fictional versions of Tokyo’s Asakusa district.

Read A fascinating biography this week: ‘Cherry’ Ingram: The Englishman who saved Japan’s blossoms by Naoko Abe (Chatto & Windus). Enjoy the story of how this gardener preserved the great white cherry tree, which was thought to be extinct.

Watch In selected UK cinemas from 22 March, Sharkwater Extinction (pictured) follows film-maker Rob Stewart as he exposes the illegal shark fin industry and the political corruption that is leading to sharks being wiped out.

Listen Learning to milk cattle, and evolving a digestive system that can just about handle dairy, may have secured the success of our species. So why give up now? BBC World Service’s CrowdScience at 8.30 pm GMT on 29 March has answers.

Pat Kane is a programme adviser to FutureFest 23 March 2019 | NewScientist | 43

CULTURE

Implausible deniability The rise of climate change denial is a compelling, if chilling, tale, finds Sandrine Ceurstemont

“WE HAVE unleashed a revolution in American energy. The United States is now the number one producer of oil and natural gas anywhere in the world,” said President Donald Trump in his State of the Union address last month. So begins a recent episode of the podcast Drilled. Perhaps it is no surprise that many US oil firms are increasing production despite a global consensus about the need to drastically reduce our use of fossil fuels to avoid catastrophic climate change. The host is journalist Amy Westervelt, who aims to tell the story behind how such climate change inaction and denial emerged in the US over several decades, involving many plot twists. The show is now in its second season, with 12 episodes released so far. Most run at less than 20 minutes, which feels short, and many lack a strong narrative. But as a whole, the podcast gives a compelling, if chilling, overview of the rise and spread of climate change denial. Although the show doesn’t reveal anything dramatically new, there will be surprises for any of us who haven’t devoted hundreds of hours to the field. For example, climate change is clearly highly politicised in the US, but there was a time when the subject was widely respected as an objective science. The podcast begins by rewinding to the late 1970s, when Exxon was developing a research centre, hiring scientists Going strong: the oil wells of California’s Central valley 44 | NewScientist | 23 March 2019

to measure carbon dioxide levels The latest report from the in the atmosphere and oceans, Intergovernmental Panel on and to create climate models. The Climate Change calls for a near firm was interested in developing 50 per cent reduction in carbon alternative sources of fuel and emissions over the next 12 years in being a wide-ranging energy to keep warming at a manageable, company rather than just relying but still dangerous, level. on oil and gas. The Drilled podcast delves That forward thinking didn’t into the climate disinformation last. Exxon sold its research campaign that has been steadily arm a few years later, when oil “In the US, climate change revenue began to shrink. And is getting harder to ignore. the government’s position on Deaths in California’s renewable energy was changing wildfires were linked to it” too. When Ronald Reagan was elected president, he abolished the subsidies for people switching infiltrating public consciousness over to solar energy put in place in the US over recent decades. by President Jimmy Carter. Oil companies, for instance, ran It is frustrating, as we now advertorials in major newspapers run out of time, to think that that often didn’t contain a we could have started to curb complete denial of climate change global warming decades ago. but rather attempted to delay

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Drilled, an investigative podcast produced by Critical Frequency

action by claiming that it wasn’t that bad and was a global problem. The campaigns were so good that they landed oil companies in court,which is the subject of recent episodes. The firms now face the same type of scrutiny as tobacco companies, which continued to sell and market products whose dangers weren’t made clear to the public. But even in the US, climate change is getting harder to ignore. Deaths have now been linked to global warming, for example, during the recent wildfires in California. And in a new court case, crab fishers on the Pacific coast are suing fossil fuel companies for economic damage. The warming oceans have created huge algal blooms that, in turn, produce a neurotoxin called domoic acid. This accumulates in crabs and makes them poisonous to eat. In 2015, the toxin’s presence delayed the crabbing season by five months, affecting the livelihoods of many crab fishers. There are still many obstacles to acting on climate change, which will be investigated in the podcast’s upcoming episodes, along with solutions. Take towns like Richmond, California, where communities have been affected by oil companies that set up shop. Chevron is a big contributor to the town’s economy, but its refinery produces a lot of air pollution. However, with proposed initiatives such as the Green New Deal, with its 10-year plan to transition to renewable energy, there is hope that the US may be able to put the past behind it. ■ Sandrine Ceurstemont is a writer based in London

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LETTERS for a vacancy. Many of these are made only to comply with benefit office demands. Trawling through them takes time and therefore money. Companies that don’t have a firm policy on looking at every application might consider only the first 40 and bin the rest. Perhaps someone could develop an artificial intelligence system capable of applying for jobs, and another that binned them at the employer’s end. The machines would be doing useful work in allowing unemployed people to get on with running their lives and seeking training and education.

Green campsite seeks a scientist in residence From Peter Lang, Green & Away, Worcester, UK I appeal for any young or experienced scientist to consider applying for the role of Green & Away’s scientist in residence. Our charity runs the leading outdoor environmental venue in the UK, near Worcester. We welcome applications from scientists in any discipline,

including ecology, economics, chemistry, physics, biology, anthropology, astronomy, psychology or sociology. The scientist in residence will be able to develop a theory and experiment on our 80-hectare farm in cooperation with our interns and volunteers, who build our environmental village between June and August. This is the first time we have offered the role, so the successful applicant will be joining a groundbreaking project. For more information, see greenandaway.org.

Fake news has existed for a long time From Clive Semmens, Ely, Cambridgeshire, UK You observe that researchers are struggling to find out how people are influenced by disinformation (Leader, 23 February). I would add to this nice piece that fake news is not an internet phenomenon. It has always used whatever medium is available. You have only to pick up a copy of some newspapers to realise that.

Finger cutting as sign of mourning in New Guinea From Ted Webber, Buderim, Queensland, Australia I lived in the Indonesian province of Papua on the island of New Guinea for two years in the 1990s. In Jayapura, I saw Dani women from the Baliem Valley who had amputated fingers in mourning for relatives. So it is interesting to read Margaret McGovern’s note on the same practice in parts of Canada (Letters, 23 February). In contrast, there are many examples of Aboriginal hand spray cave art in Australia but none that I have seen feature incomplete fingers.

Neanderthals lived where the warmth is From Rick McRae, Canberra, Australia Laura Spinney reports Matt Pope’s view on where to look for Neanderthal habitation: a third of the way up a slope with a good vista and solid rock behind (9 February, p 28). Studying wildfire risk factors, we found

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“thermal belts” in exactly these places on spurs of high ground, with higher temperatures and lower humidity than adjacent zones. They require clear skies. These belts can be 7°C or more warmer than neighbouring ground. If the sites were indeed “optimised” for this, that could lead us to make interesting inferences about Neanderthals’ understanding of their environments.

Ban the wearing of ties to fix air-con problems From Hillary Shaw, Newport, Shropshire, UK Scott McNeil notes that people from different places want open plan offices to have different temperatures (Letters, 2 March). There is a gender difference too: women who want or are required to dress fashionably may wear less clothing than men in suits. The moral suasion on men to wear suits and ties results in clothing that is too cold for winter and too hot for summer. We could save a lot on air conditioning and heating costs by banning ties from offices, or maybe have an environmental tie tax, easily enforceable by unannounced visits from the tie tax inspectors.

For the record ■ Riverrun: going eastward we find the Thames, Scheldt, Meuse and Rhine rivers (9 March, p 30). ■ The substance we should cautiously welcome as a treatment for depression is esketamine, one of the mirror-image molecules that make up ketamine (16 March, p 24).

Letters should be sent to: Letters to the Editor, New Scientist, 25 Bedford Street, London, WC2E 9ES Email: [email protected] 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 | 23 March 2019

FROM THE ARCHIVES Twenty-five years ago, the advent of Prozac seemed to herald a new era in manipulating our brains

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“IT’S winter 2030. Work is going badly, your love life is in tatters. Feeling irritable and melancholic, you reach for your computer and call up Normopsych, an on-line drugs service specialising in personality restructuring.” Such was the vision of the future that opened a New Scientist feature entitled “Design your own personality” on 12 March 1994. A quarter of a century ago, the first graphical web browsers had only just been released, so we were ahead of the curve with our vision of the future “on-line”. But the real trigger for the article was a new class of drugs that had just hit the market. The antidepressant Prozac was causing a media stir, and other drugs that seemed to increase the amount of the happiness-linked chemical serotonin in the brain were in development. This offered a taste of things to come, said psychiatrist Peter Kramer in the feature. His bestselling book Listening to Prozac had claimed that the drug not only improved mood, but could also transform personalities. According to the article’s strapline, popping a pill might soon “turn wallflowers into social butterflies and couch potatoes into go-getting executives”. It seemed as if it were simply a matter of deducing which chemicals did what in the brain, and then “selecting compounds that can influence the workings of specific neurotransmitter pathways”. Many saw conditions like depression and anxiety as being on a spectrum of personality traits such as introversion and shyness. We now know it isn’t that simple. The precise effect of neurotransmitters on mood has only become less clear, and we are still a long way from understanding exactly how drugs such as Prozac work. The conflation of personality traits and mental illness is very much of its time, too. Even the notion that mental illness is the result of a chemical imbalance in the brain is losing ground. Sometimes in science, the more we learn, the more our ignorance becomes apparent. Julia Brown ■

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FEEDBACK

Feedback to some Colorado bars in the name of, er, research.

PAUL MCDEVITT

MATHEMATICS teacher Orly Selouk has come across a problem in the UK Intermediate Mathematical Challenge which, she says, “I am sure would make your collective eyes roll.” Students are asked about an amount of plastic waste “as heavy as 25 Empire State Buildings in New York or a billion elephants. On that basis, how many elephants have the same total weight as the Empire State Building?” On the contrary, this is exactly the sort of question students need to master if they are to make sense of how the world is described in popular newspapers and magazines.

AIRLINE food is the butt of untold stand-up routines – or it was, until budget airlines came along and made it a rarity. But London Stansted Airport is coming to the rescue with a sandwich it claims is engineered to taste good at cruising altitude. Food scientists created it for London’s third busiest airport to give passengers a “premium in-flight taste experience”, thanks to a “special blended umami seasoning” which they say cuts through the impact of soul-deadening engine noise on our sense of taste. Don’t forget the crying babies and rowdy stag parties too. As for the fillings, given it is named the Sky High Sandwich, Feedback is up for turkey, stuffing and cranberry with a light benzodiazepine dressing.

SPEAKING of which, Feedback has long subscribed to the philosophy that almost all meals can be divided into a holy trinity of stew, salad or sandwich. Stir-fry? Mainly vegetables, therefore salad. Jambalaya? A rice stew.

Pizza? A splayed-out sandwich. Even Feedback would admit limits to our categorisation system with a delicacy such as chicken wings, however. Not so the authorities in Colorado, where some bars are required to serve light snacks in order to sell alcohol. Owners had been pressing for guidance on what constitutes a light snack, leading to the curious 2016 Title 12 Colorado Revised Statute (C.R.S.). It declares: “ ‘Sandwiches’ as used in articles 47 and 48 of Title 12, C.R.S. are defined as single serving items such as hamburgers, hot dogs, frozen pizzas, burritos, chicken wings, etc. ‘Light snacks’ as used in articles 47 and 48 of Title 12, C.R.S. are defined as popcorn, pretzels, nuts, chips, etc.” Why chicken wings are considered a sandwich and not a light snack is a mystery only lawmakers are party to. Perhaps our editors will consider sending

“We didn’t understand that you can’t make certain claims… We just thought we were like, writing a blog.” Gwyneth Paltrow explains how Goop’s vaginal yoni eggs fell foul of advertising rules 56 | NewScientist | 23 March 2019

FOLLOWING correspondence on the volume of water as measured in penguins (18 December 2018), James Fenton lets us know the value of a gentoo penguin: 1/20th of an off-road vehicle. “In the zoo trade, money isn’t allowed to change hands when transferring species, so that when a European zoo donated 20 penguins to another it was agreed instead to provide a new Land Rover to a conservation project being run in the Falkland Islands.” “I KNOW you're never, ever going to mention nominative determinism again,” writes Galen Ives, “but I can't help pointing out that there's an emeritus professor of psychiatry at Zurich University called Jules Angst.” No worries, Galen – Feedback noted the existence of the appropriately monickered prof as far back as 1992 (10 October). But we are superrelaxed about noting it again.

THE construction of metro line 6 in Chongqing, China, into areas where nothing yet exists to visit (9 March) “is no more strange than the original Metropolitan Line in London, which passed through largely agricultural areas”, says Ian Moseley. Rather more strange, he says, is Redcar British Steel station, the least used railway station in the UK. “Apparently it has only around

40 passengers per year, and is surrounded by private land so you can’t leave the platforms.” WHO will be feeling the heat most  at the Tokyo 2020 Olympics? In the journal Temperature, mathematician Nathan Downs modelled the city’s climate to see which events would expose athletes to the most sun. Golfers and cyclists can expect a tan, but the vagaries of scheduling mean a high proportion of the women’s tennis matches are being played around midday, requiring them to slap on the most sunscreen. One for the equality authorities?

ALAS, poor Jibo: the servers powering the pioneering social robot are shutting down. Multiple owners report that Jibo itself has been delivering the sad news, lamenting: “Maybe someday

when robots are way more advanced than today, and everyone has them in their homes, you can tell yours that I said hello.” FINALLY, John Farquhar-Atkins has stepped up to the challenge of making nursery rhymes scientifically, if not perhaps entirely metrically, sound (9 March). He writes: Twinkle twinkle little star, I know precisely what you are, Nuclear furnace in the sky, You’ll burn to ashes by and by.

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THE LAST WORD Dunny roaming Many workplaces I visit have a row of three toilets. If all three are available and I want to use the least visited – and hopefully cleanest – which should I choose?

Q I once researched this for a psychology assignment. The furthest cubicle from the door, which was bordered by a wall and perhaps gives a greater sense of privacy, was used most often. If it was occupied, the first was chosen. I found that there was seeming reluctance to use the middle one even if the others

Q There are two reasons for a lavatory break at work. If for a “call of nature”, the first toilet stall will see the most action, as it provides “My experience as a cleaner in a girls’ high school tells the quickest route to relief. me the first toilet cubicle The other reason for a visit is is the least used” very different: to liberate mind and soul from the routine of work life. The cubicle, while physically were occupied. Around a third of restrictive, is a wonderful potential users in that situation environment for the repressed would walk out. mind to wander at will, briefly Based on this, it seems the freed from the whir of machinery middle toilet is the least used. or endless spreadsheets. In this Peter Skuse case, the third cubicle is best, as Whyteleafe, Surrey, UK it provides the greatest physical Q My experience as a cleaner in distance from the workplace. a girls’ high school tells me that I would therefore expect the you should choose the first second cubicle to be the least cubicle. I always had to top up used and therefore cleanest. the toilet paper more often in Mike McCullough the second and third cubicles London, UK compared with the first. Mere Bianchin Q The TV show Mythbusters found the fewest microbes in Hamilton, New Zealand the stall closest to the door. The explanation it gave was that Q The assumption that the least-visited toilet is the cleanest everyone assumes others take is probably wrong. Look at the the closest stall, so they take the problem the other way around. Is furthest one. That was the most the dirtiest toilet going to attract contaminated. the most visitors, or the fewest? It also discovered that there With all three toilets available, were many more microbes on simply pick the one that looks keyboards and phone handsets the cleanest. than toilet seats. Howard Bobry Mark Carter Nehalem, Oregon, US Germantown, Maryland, US

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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/

Net effect What is the worst that could happen if the entire world’s internet were to go down for a day? (Perhaps we could do this intentionally and make it an international holiday!)

Q While a long-term shutdown could be catastrophic, a 24-hour outage would have manageable impacts. The loss of many forms of communication would affect small businesses most, as they are often the least resilient. A bigger concern would be a complete freeze on all e-commerce and financial transactions. If everyone knew the outage was temporary, then issues could be minimal, but a surprise outage with no known ending could cause panic and chaos. The saving grace would be that a financial market crash would be less likely with limited communication. Lewis O’Shaughnessy London, UK Q Utility systems, such as gas, electricity and water, could be curtailed. Banking and finance would struggle to function. Police and other public services using shared databases would be hampered. Have a great day at home, because you wouldn’t want to go far. Peter Harris Sutton Coldfield, West Midlands, UK Q One effect would be a sudden reduction in electricity demand: the internet and devices related to

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its use consume a vast amount of electricity. This means it is also responsible for significant carbon dioxide emissions. By some estimates, shutting it down for a day would prevent the release of around 4 million tonnes of CO2. Anthony Roberts Rushden, Northamptonshire, UK Q The worst effect would be psychological. When we have no experience of or direct control over an event, and the outcome is serious but unquantifiable, it is inevitable that we will store this as a fear memory. Daelyn Nicholls Finley, New South Wales, Australia Q Cars could still be driven and computers could still be typed on, so productivity would slow, but not grind to a halt. Given the impact of time differences, for most of the world, a 24-hour blackout would only cover part of the working day, so some work could be completed before or after it happened. Theo Megarrity Brisbane, Queensland, Australia

This week’s question CANINE CONNECTION

While quietly walking my small dog, we often pass houses where the dog inside, which is out of sight, begins barking. How does the dog know to bark if it can’t see, smell or hear us? Ross Bowden Melville, Western Australia