11 August 2018, No3190 New Scientist (Australia)

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A BRIEF HISTORY OF GRAVITY • A LIFE IN BRAIN SURGERY • BLUE PLANET, UNSEEN WHO ARE WE AND HOW DID WE GET HERE? • THE NATURE OF TIME

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DEFENDING EARTH FROM ASTEROIDS • EXOPLANETS, ON THE HUNT FOR UNIVERSAL LIFE THE FATE OF THE COSMOS • GRAVITATIONAL WAVES: SIRENS OF THE COSMOS JOURNEYS INTO PARTICLE PHYSICS • THE DARK SIDE OF THE UNIVERSE EARTH STAGE

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PREVENTING AND OVERCOMING CHRONIC PAIN • CAN YOU LIVE FOREVER (AND WOULD YOU WANT TO)? TECH NOLOGY STAGE

HOW QUANTUM SENSORS CAN IMPROVE OUR LIVES • SHOULD ROBOTS HAVE RIGHTS?

IMAGING EARTH’S SECRETS USING COSMIC MUONS • MATHS VERSUS AI • THE HIDDEN SECRETS OF EGYPTIAN MUMMIES THE PAST, PRESENT AND FUTURE OF ARTIFICIAL INTELLIGENCE EXPERIENCES

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LISTEN UP Sound waves are made of antigravity

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THE ALLERGY EXPLOSION Why they’re on the rise — and how to protect yourself

ANTARCTIC SHOCK

3 2

Now its other half is melting too PLUS THE MAN WHO LOST TIME/WHAT KILLED THE MAYANS? News, ideas and innovation www.newscientist.com

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Insight Tracking killers through their families 20

On the cover

Leaders

20 Family guilt Distant relatives’ DNA can get you jailed 7

Web development Maria Moreno Garrido, Tuhin Sheikh, Amardeep Sian

Volume 239 No 3190

Listen up Sound waves are made of antigravity

3

News 4

THIS WEEK Now the other half of Antarctica is melting too. Drone jammer saves president. Fentanyl deaths. Lombok quake

6

NEWS & TECHNOLOGY AI spots football injuries before they happen. Boy’s brain works fine after piece removed. Hibernating animals can’t develop big brains. Sound waves have negative mass. Robots that find oil spills. Emoji headset helps autistic kids spot facial expressions. Modified mosquitoes stop dengue problem. Small dogs urinate higher. Lab-grown lungs work in pigs. Did drought bring down the Mayans? Dark matter from another galaxy

13 Urine for a surprise Smaller dogs pee higher 28 The allergy explosion Why they’re on the rise – and how to protect yourself 4

Antarctic shock Now its other half is melting too

Plus The man who lost time (40). What killed the Mayans? (14)

Our networked world needs better approaches to cybersecurity. Allergies aren’t imaginary maladies

17 IN BRIEF AI spots bad grapes. First Stonehenge burials. Lemurs use millipedes to self-medicate

Analysis 20 INSIGHT Tracking killers with their family’s DNA 22 COMMENT We don’t need to worry about fake videos. Why lab beef is riling farmers 23 ANALYSIS 3D-printed weapons distract from the real gun issue

Features 28 The allergy explosion What’s causing it, and how to survive it 34 Into the deep Jon Copley reveals the secrets of diving for Blue Planet II 36 Can’t hack it We can end cyberattacks – if we radically redesign the computer chip 40 The man who lost time Michel Siffre conducted an incredible experiment on his own body clock

Culture 42 Unleash your virtual hero We try out Marvel’s new VR game 43 How Ötzi came to life A delicate film portrait of an ancient iceman. PLUS: This week’s cultural picks 44 Amazing apians Bees are beautiful and diverse, even if they’re just hippy wasps

Regulars 26 APERTURE Master of disguise 52 LETTERS A theory of mind solution 55 CROSSWORD 56 FEEDBACK Blueberry Earth 57 THE LAST WORD Flower underpower

11 August 2018 | NewScientist | 1

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IT WAS an innocent mistake, with huge consequences. Robin Seggelmann was a programmer working on OpenSSL, a software library used to make secure connections over the internet. In 2014, it emerged that a tiny error of his – likened to misspelling “Mississippi”, and all but invisible in 400,000-odd lines of code – had allowed the world’s hackers into the servers of Google, Amazon, Facebook, Tumblr and more, exposing sensitive personal data including credit card numbers and passwords. It’s not Seggelmann’s fault; more just one of many indictments of our slapdash

approach to computer security. It took two years before anyone noticed the bug, dubbed Heartbleed. By then, it was affecting pretty much every server in the world. The only solution was to patch the software, and hope for the best. That’s not good enough. This year, the World Economic Forum listed cyberattacks and data fraud in its top five most likely global risks, alongside extreme weather, natural disasters and the failure to tackle climate change. It estimated that cyberattacks will cause $8 trillion of losses in the coming five years. As critical infrastructure becomes more and

Allergies aren’t nuts Environment ISO 14001 Certification applies to Offset Alpine Printing

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LOVERS of nuts – and freedom – suffered a blow on 1 August, when the US budget carrier Southwest Airlines went peanut-free. While many parents of children with allergies expressed thanks, other people took to the internet to announce they would be bringing their own supply from now on. If you were born before the 1990s, or don’t have children,

peanut bans by airlines, schools and workplaces can feel like a gross overreaction. Allergies may seem like modern maladies, but that does not make them any less real or life-threatening. This isn’t simply a case of hypochondria or increased vigilance – cohort studies that have closely followed different generations for decades confirm

more interconnected – potentially even to your kettle and toaster if the “internet of things” ever truly becomes reality – we create more points of vulnerability that can be exploited. It is time to call time on the era of the digital sticking plaster that is the software patch. More effective ways of protecting a networked society exist at the level of computer hardware (see page 36). They would require an overhaul of the way we do computing, and are unlikely to be a panacea. But the price of the innocent mistakes allowed by our current software-based way of security is simply too high. ■

that hay fever, allergic asthma and food allergies have all risen since the mid-20th century in the developed world. Rapidly developing nations such as China are now beginning to see an increase in allergies too. The challenge is to work out why, and dispel some of the many other myths surrounding allergies (see page 28). In the meantime, whether afflicted or non-afflicted, we must all learn to live with them. ■ 11 August 2018 | NewScientist | 3

THIS WEEK

Antarctica’s shock new loss Two huge glaciers are rapidly melting, says Michael Marshall

ANTARCTIC PENINSULA

SOUTH POLE

WEST ANTARCTICA

Totten glacier outlet Moscow University glacier

over the place. In 2015, one team even claimed it was gaining ice. Adding to the confusion, the sea ice around Antarctica had grown in recent years. But the amount of this ice is minuscule compared with that in the continent’s ice sheet, and the sea ice has shrunk again over the past two years.

ARCTIC DANGER The Arctic is already warming at twice the rate of the rest of the planet. Now a little-known natural cycle in the Pacific is entering a phase that could make it heat up even faster. The rapid warming of the Arctic is causing seasonal sea-ice cover around the Arctic Circle to retreat by a record amount. The warming is also disrupting weather patterns and could be a key factor behind the current heatwave. A bit like El Niño, the Pacific Decadal Oscillation (PDO) is cyclical, switching from warm to cold phases every 20 years or so. Its phases are

4 | NewScientist | 11 August 2018

EAST ANTARCTICA

NASA

TWO vast glaciers in East Antarctica have been losing mass rapidly since 2002. The finding means that our forecasts for sea level rise this century will have to be revised upward – and we don’t know by how much. So far, most of the ice lost from Antarctica has come from West Antarctica – in particular the Antarctic Peninsula, which juts out to sea and is exposed to warmer water. The Larsen C ice sheet, which infamously cracked in 2017, is in West Antarctica. East Antarctica, which makes up two-thirds of the continent, was thought to be more stable because the strong winds spinning around Antarctica prevent hotter air from entering. So although Antarctica, like every continent, is warming, it is unclear how much global warming is needed to melt East Antarctica. One challenge in attempting to find out is East Antarctica’s remoteness. Glaciologists have tried to estimate what is happening there, but for decades their measurements have been all

dictated by Pacific sea surface temperatures. The warm phase sees higher temperatures in the tropical Pacific and along the western coastline of America, with colder temperatures in the north. The pattern reverses in the cold phase. The upshot is that, as the warm phase kicks in, it could amplify warming in the Arctic. “It’s possible it will warm the Arctic even more,” says Lea Svendsen at the University of Bergen in Norway, who is head of the team investigating the effect of the PDO. “But we need to wait at least another 10 years or so to find out.” Andy Coghlan

Two glaciers show global warming is already affecting East Antarctica

To learn about the true situation, Yara Mohajerani at the University of California, Irvine, and his colleagues focused on two vast East Antarctic glaciers called Totten and Moscow University (Geophysical Research Letters, DOI: 10.1029/2018GL078173). As recently as 2015, a major survey of Antarctica’s glaciers hedged its bets on whether Totten was shrinking. But evidence has accumulated since then. Calculations based on estimated snowfall and the glacier’s observed speed suggested it was losing mass. A study published in November 2017 examined the Totten ice shelf, the region where the glacier meets the ocean and goes afloat. This found that it flowed into the sea faster between 2001 and 2006, when the water was a little warmer than usual, suggesting it was vulnerable. Then in March this year, researchers announced that more of the

glacier was floating than thought, meaning it was more exposed to warm currents. “We used multiple lines of evidence to confirm significant mass loss from Totten and Moscow University glaciers,” says Mohajerani. In particular, the team used data from the

“The two glaciers hold enough ice to raise sea levels around the planet by 5 metres” two GRACE satellites, which measure local changes in the strength of Earth’s gravity. Less ice in the glaciers means they have less mass and thus a weaker gravity field. Between 2002 and 2016, the two glaciers lost an average of 18.5 gigatonnes of ice every year, the team estimates. The glaciers hold enough ice to raise sea levels by 5 metres. Totten alone could cause a 3-metre rise. “It’s extremely unlikely that that amount of ice will emerge in this century,” says Sridhar Anandakrishnan at Penn State University. That is because it takes time for warm seawater to eat its way back through the glacier. But while we probably won’t see a 5-metre rise by 2100, we could get a lot and we don’t know how much. What is clear is that previous uncertainty about the state of East Antarctica has largely vanished, says Anandakrishnan. It is losing mass and has been for some years. “I think the consensus was overly conservative and cautious,” he says. At this point, “the consensus is shifting quite strongly that East Antarctica is indeed losing mass, end of story”. ■

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

Hothouse Earth fears the present interglacial state and into

dioxide into the atmosphere and limit global warming to 2°C, a cascade

the hothouse Earth state (PNAS, doi.org/gdxtms). This means that

of tipping points may result in

even if all our greenhouse gas

warming of 4 or 5°C, warns a group

emissions ceased and we managed to

of 16 climate scientists. With that

limit warming to 2°C by 2100 – we are

would come additional sea level rise

currently on course for 3 or 4°C by

of between 10 and 60 metres. For most of the past half billion years, Earth has been much hotter

then – warming would continue over

than today, with no permanent ice at

underestimate warming by at least

the poles: the hothouse Earth state.

0.5°C, because they don’t include all

Three million years ago, as CO2 levels

feedbacks, such as less carbon being

fell, it began oscillating between two

stored in oceans or forest dieback. As

cooler states: ice ages with great ice sheets covering much land in the

Earth warms, more will be triggered. The team stresses it is pointing

northern hemisphere and interglacial

out a risk that needs studying, not

periods like the present. If Will Steffen at Stockholm University in Sweden and his

something that is certain to happen.

colleagues are right, we might be on

scepticism at the claim, although

the brink of pushing the planet out of

others thought it was reasonable.

Assassin drones Another quake fail to kill president rocks Lombok

neighbour Bali, where the tremors

Use of powerful opioid rising in UK

RADIO jamming systems apparently

AT LEAST 98 people have died and

of houses on Lombok, some of which

THE drug fentanyl was behind

thwarted an attempted presidential

thousands have been left homeless

collapsed in Sunday evening’s quake,

75 deaths in England and Wales last

assassination with improvised drone

by a powerful earthquake on the

measured at magnitude 6.9 by the

bombs in Venezuela.

Indonesian island of Lombok.

US Geological Survey.

year, up 29 per cent from 58 in 2016. Fentanyl is a synthetic opioid that

On Saturday 4 August, President Nicolás Maduro’s speech at an

Thousands of people are now sheltering in makeshift tents.

In the mountainous north of the island, more than half the homes

can be up to 100 times more powerful

outdoor rally was interrupted by two

Authorities say rescuers haven’t

were destroyed or severely damaged.

released by the UK Office for National

explosions. People scattered and

yet reached all affected areas and

president with bulletproof shields.

expect the death toll to climb. It was the second deadly quake in a

Collapsed bridges, blocked and ruptured roads and the loss of power

Statistics on Monday, also reveal that

bodyguards rushed to protect the

and communications have so far

than fentanyl – was mentioned on

Witnesses reported seeing two

week to hit Lombok, a less-developed

prevented rescuers from reaching

death certificates for the first time in

drones, which crashed into a nearby

island compared with its more famous

some affected areas.

apartment building and exploded. Seven people were injured, said

2017, accounting for 27 deaths. However, deaths from most other opiates seem to be in decline. In 2017

Nestor Reverol, Venezuela’s interior

there was a 4 per cent decrease in

and justice minister. He announced on

heroin and morphine deaths, down to

television that the attack was carried

1164 people. This is the first drop in

out with two DJI Matrice 600 drones,

deaths from these drugs since 2012. Deaths from the stimulant cocaine have risen for the sixth year

DAVE WALSH /EYEVINE

EVEN if we stop pumping carbon

are larger professional versions of the firm’s popular consumer drones. Reverol said each drone had been carrying a kilogram of C-4 explosive, and that “signal-inhibiting equipment” caused one to fall short of its target, and the other had crashed. In other words, that equipment was probably a jammer of some kind.

ADI WEDA/EPA-EFE/REX/SHUTTERSTOCK

a type widely used for filming, which

caused panic and damaged buildings. A quake on 29 July killed 16 people and damaged hundreds

the next few centuries. The group also argues that existing models

Some climate scientists that New Scientist spoke to expressed

than morphine. And the new figures,

carfentanyl – which is even stronger

in a row. In 2017, 432 people died from powdered or crack cocaine use, up from 371 the previous year. Overall, the level of drug poisoning deaths in England and Wales has remained stable from the previous year, says Ellie Osborn of the Office for National Statistics. 11 August 2018 | NewScientist | 5

NEWS & TECHNOLOGY

Secret AI predicts football injuries FOOTBALL may be unpredictable, but its injuries often aren’t. Artificial intelligence can work out when players are likely to get hurt, so coaches can let them rest. A machine-learning algorithm developed by data scientists at the University of Pisa, Italy, and Barcelona football club recently predicted nine out of the 14 injuries sustained by an elite Italian football team during a single season. Alessio Rossi at the University of Pisa and his colleagues fitted the football team’s 26 players with GPS sensors during their training sessions. These measured how far and fast they ran, how often they accelerated and decelerated, and the impact they had with the ground and other players. They also recorded information about their age, height, weight, role on the field, injury history and minutes played in the last game. As the season progressed, the researchers’ algorithm learned to detect patterns between these variables and players getting hurt. By the end, it was able to predict

Boy’s brain works despite missing a chunk A BOY who had a large portion of his brain removed is still able to function normally, showing how adaptable our brains can be. The boy started having seizures at the age of 4, as a result of a tumour, leading surgeons to remove a third of his brain’s right hemisphere just before his 7th birthday. This “lobectomy” excised his right occipital lobe, which carries 6 | NewScientist | 11 August 2018

about 60 per cent of injuries. Coaches could use the algorithm to work out when they should rest a player or lighten their training load, says Rossi. For example, if Uruguay’s manager had known that Edinson Cavani was at risk of injuring his calf in the recent World Cup match against Portugal, he could have

Predictable? Manchester United’s Romelu Lukaku massages his calf

out visual processing, and most of his temporal lobe, which deals with sights and sounds. But no one knew how the boy’s brain would recover after losing one of its visual centres – we usually have two, one in each brain hemisphere. “Higher order” visual capabilities, such as recognising faces and objects, are mainly the job of the right hemisphere. Three years after the surgery,

all normal for his age (Cell Reports, doi.org/cssk). But he can’t see the whole visual field. “He is essentially blind to information on the left side of the world,” says Behrmann. It seems we need two hemispheres to have full 180 degree vision, she says. Although the boy’s ability to “see” with the right-hand side of his brain never recovered, the team found that his left hemisphere reorganised itself to take over sophisticated tasks such

MATT WEST/BPI/REX/SHUTTERSTOCK

Alice Klein

replaced him sooner, says Rossi (PLOS One, doi.org/gdwzrp). Sports injury forecasters have been used in the past, but their precision has typically been less than 5 per cent, says Rossi. This is because they have usually relied on a single variable – like the number of balls a cricket bowler bowls – to predict injury risk, he says. “They miss the power of combining different training workload measures,” he says. Existing forecasting tools have

Marlene Behrmann of Carnegie Mellon University in Pennsylvania and her colleagues found that the boy’s intellect, visual perception and recognition of faces and objects were

also been hampered by high false alarm rates, says Rossi. “Stopping players unnecessarily is a condition clubs want to avoid, especially for key players,” he says. The new forecaster halves the rate of false alarms, he says. The Italian team that trialled the AI can’t be named because it doesn’t want to give away a competitive advantage, says Rossi. The same goes for three other top-level European football teams that have started using it, he says. Rossi and his colleagues are now investigating whether they can increase the accuracy of predictions by including variables like heart rate and degree of sweating. They want to see whether they can predict the type of injury, although some will always be unpredictable, following a bad tackle, for instance. Microsoft launched its own machine-learning injury forecaster in June last year, which uses GPS and heart rate data, as well as players’ self-reported sleep, mood and muscle soreness. It is being used by US football team Seattle Reign, Spanish football team Real Sociedad, the Seattle Seahawks NFL team and the Australian cricket team. Their results are mostly confidential, but Seattle Reign says only one player got injured in the season after the team adopted the technology. ■

as face and object recognition. This hemisphere is normally more involved in tasks like recognising words. “We saw a kind of jostling in the left hemisphere between regions engaged in word and face recognition, which resolved and settled into a new organisation,” says Behrmann. It may have been possible to recover these abilities because they were still developing at the time of the lobectomy, says Behrmann. Older people who lose a visual centre may not fare as well, she says. The boy says he wants to be

“Three years after the major surgery, the boy’s intellect and visual perception were a neurologist when he grows up. Alison George ■ normal for his age”

For daily news stories, visit newscientist.com/news

Don’t hibernate if you want a big brain MAMMALS that hibernate for part of the year tend to have smaller brains than those that can feed all year round. The finding may help explain why big-brained primates like us mostly evolved near the equator, where the seasons are much weaker and there is less reason to hibernate. Sandra Heldstab at the University of Zurich, Switzerland, and her colleagues compiled data on 1104 mammalian species. They looked at the size of each species’ brain relative to its body, and whether or not that mammal hibernated. Those mammals that did had significantly smaller brains relative to their bodies, even when the team animals’ diets (Journal of Evolutionary Biology, doi.org/cssv). “Hibernation really is a constraint for brain size,” says Heldstab. The team argues that this is because it takes a lot of energy to grow and run a large brain, an idea

GETTY

controlled for other factors like the

Listen up: sound waves have negative mass

called the expensive brain hypothesis. Seasonality in food availability – a reason for hibernation – would prevent animals having the constant high energy supply needed to grow such a brain. Primates, the group that includes monkeys, apes and humans, mostly live in places near the equator. The lack of seasons there, which means no need to hibernate, is probably one of the reasons why so many primates have evolved large brains, says Heldstab. Even today, only a handful of primates hibernate. “There’s just three orders of lemurs which hibernate, and these three have the smallest brains in primates,” says Heldstab. However, once a species has evolved a big brain, the additional intelligence it gains may then allow it to colonise more seasonal places. In line with this, there is evidence that successful invasive species tend to have larger brains. Michael Marshall ■

HEAVY metal music isn’t heavy wave moves, its path will bend after all – it is actually the opposite. upwards, away from the pull of Sound waves have mass and can gravity. “Heavy metal music, interact via gravity, but that mass given a long enough time, is is negative. In other words, sound probably going to start floating floats upwards. in air, so it is probably not that Angelo Esposito at Columbia heavy,” says Riccardo Penco at University in New York and his the University of Pennsylvania. colleagues calculated the relationship between sound and “Heavy metal music, given a long enough time, is gravity, taking into account complicated particle interactions probably going to start that had previously been ignored. floating in air” They found that, although the effect is small, sound waves Of course, the same is true no should have negative gravitational matter the genre of music. mass (arxiv.org/abs/1807.08771). In some sense this is a trick of “It’s almost like antigravity,” mathematics because a sound says Ira Rothstein at Carnegie wave is simply an excitation of a Mellon University in Pennsylvania. medium and not a particle with “The atoms that are moved by the a true mass, but the sound really wave are still being pulled down is being affected by gravity. by Earth, but the sound wave itself “If you were to weigh a sound is being repelled.” wave using a scale, it wouldn’t be This means that as a sound mass in that sense,” says Walter

Goldberger at Yale University. “But it is mass in the sense that this thing gravitates.” The sound wave’s negative mass is not absolute, but rather relative to the density of the medium. That means that this negative mass can’t exist in a vacuum, where sound has no medium to travel in, which is fortunate because such a thing would break a number of laws of physics. “A negative potential in a vacuum would be rather insane since it would require truly negative masses,” says Esposito. Performing an experiment to measure this predicted effect will be difficult, because observing it requires extremely strong gravitational fields or an extremely dense medium for the sound wave to travel through. It could be done using clouds of molecules cooled to near absolute zero, or an extremely strong sound wave like that created by a particularly powerful earthquake, says Esposito. It could also be seen in exotic materials like superfluid helium, which has zero viscosity when chilled to near absolute zero. A sound wave travelling through this weird liquid in normal gravity would have a negative mass equivalent to the positive mass of a single helium atom. After travelling 100 metres, it would have floated upwards by about 1 metre. There are other strange consequences of sound having negative mass. Just as two objects with positive masses will attract one another, two waves with negative masses will do the same. So if two people were screaming while facing the same direction, given enough time the two screams would bend towards one another and merge, says Esposito. “But they would have to be screams with really large energies or in an extremely dense area like the centre of a neutron star,” he says. “Don’t try it at home.” Leah Crane ■ 11 August 2018 | NewScientist | 7

NEWS & TECHNOLOGY FIELD NOTES Celtic Sea

Robots hunt for oil spills underwater oil. But we have no good way of tracking oil underwater, and it is tough to make those calls without knowing if there is a lot of oil sloshing around out of sight. Gilabert’s idea was to deploy a team of autonomous underwater vehicles (AUVs) with instruments that can detect the way oil fluoresces when you shine a light on it. They can then provide responders with an evolving 3D map of the plume. To simulate the spill, the naval officers in the dinghy are releasing a dye called rhodamine, which has chemical bonds that fluoresce in a similar way to oil. The five AUVs then begin to crisscross the patch of dye. The difficult part is getting the communications to work, both so the AUVs know their position and so they can relay information back. Radio signals don’t travel well underwater but sound does. So the team send signals via Wi-Fi to floating stations, which then relay them to the AUVs using an

Joshua Howgego

A SMALL dinghy bobs on the ocean a few miles off the Irish coast. Two men in dark clothes lower a pipe into the water, switch on a pump and chemicals start to flow. To the untrained eye, it looks distinctly dodgy. But these men are from the Irish navy and the chemicals they are dumping are creating a simulated oil spill, to be sniffed out by a

“Oil can behave strangely in water, spreading out then popping up in unexpected places”

8 | NewScientist | 11 August 2018

Careful – underwater robots don’t come cheap

BOTH PHOTOS: TECHNICAL UNIVERSITY OF CARTAEGENA

team of robots lurking in the depths below. I’m aboard LÉ Róisín, an Irish Naval Service patrol ship, with a team of scientists who think they have a uniquely effective way of dealing with oil spills. The project leader is Javier Gilabert of the Technical University of Cartagena, Spain. Inspiration came to him following the huge Deepwater Horizon spill in 2010. The accident drove home how strangely oil can behave in the water. Much of it didn’t rise straight from the ruptured well to the surface but remained trapped in the water column, where it spread out and then “popped up in unexpected places”, says Gilabert. Emergency responders can use satellites to spot the rough location of oil on the surface, then track it closely using radar on planes or by eye from boats. This helps them decide on their tactics: whether to use floating booms to hem in the oil and vacuum it up, or add chemicals called dispersants to help dissolve the

acoustic signal. Soon things are working and researchers with laptops on plastic tables have a 3D model of the spill. This isn’t the first exercise of its kind. Gilabert and his team also tested things out in the Mediterranean in 2015 and 2017. But there they worked from a special ship that could use its thrusters to remain still in the water. This time things were more challenging and realistic. The navy ship is built primarily for speed, not stability, and the rocking of the antennas meant that the team twice lost contact with the AUVs, some of which are worth more than £100,000 because of the sophisticated sensors on board. On the second day, tests had to be called off; the black waters of the Atlantic were so rough that the AUVs could easily have smashed against the ship while being retrieved using mechanical winches. There are ways of fixing those problems. You might use a static balloon as a communications base station, for example, says

This navy boat dumped chemicals in the ocean for good reason

Gilabert. And to get around the problems of retrieving the AUVs, you could program them to head to shore on their own. “We have learned many things and we’re close to making this a reality,” Gilabert told the team below decks at a wrap-up meeting. Plenty of people are interested in the project, which is known as Enhanced Underwater Robotics Ready for Oil Spill (eURready4OS), including professional response firms funded by the oil industry to help clean up big spills. Then again, you can only learn so much without working with real oil, which is why – just occasionally – training exercises like this release the real stuff into the ocean. Industry-funded cooperative Oil Spill Response Limited is planning one such exercise in the next few years. It may sound like a terrible idea, but when the next big spill happens we need to be ready for it. ■

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Cutting-edge Japan: from Tokyo to Okinawa Explore the diverse faces of Japan. Journey from buzzing Tokyo to snow-capped mountains; from hot springs to subtropical coral reefs DEPARTURE:

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OUTSTANDING NATURAL BEAUTY In the shadow of Mount Fuji, visit the volcanic Owakudani valley and walk between steam vents and hot springs. Then catch the bullet train to Kyoto and explore its peaceful temples and lavish gardens where bamboo thickets crowd the skyline.

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TAKE PART IN RESEARCH Round off your trip with three days on the subtropical island of Okinawa. Get stuck in at the Okinawa Institute of Science and Technology where you’ll take part in environmental research, learn about sustainable living and how coral is being restored.

SPE A K T O OUR SPE C I A L IS T T E A M AT S T E PPE S T R AV E L T O F IND OU T MORE Visit newscientist.com/travel/Japan or call +44 (0)1285 600 129

NEWS & TECHNOLOGY Modified mozzies wipe out dengue DENGUE virus has effectively been expunged from an Australian city following the release of anti-dengue mosquitoes in 2014. JEFF CHIU/AP/REX/SHUTTERSTOCK

Townsville in Queensland has recorded zero cases of locally transmitted dengue in the four years since the modified mosquitoes were released, compared with 54 cases in the previous four years. The trial represents the first successful use of modified mosquitoes to eliminate

Emoji glasses give autism boost Poppy-Jayne Morgan

It detects expressions in real time and then displays matching emojis in the corner of the glasses, as well as describing the emotion via the headphones. The idea is that the children find it easier to spot the emotion when it is displayed this way. To find out if the set-up had any effect, the team asked parents to assess their children before, during and after wearing the glasses. They did this using the

MANY children diagnosed with autism find it hard to decipher other people’s facial expressions. An interactive system that uses Google Glass may help them out. “I can see the difference this will have in people’s lives in a significant, immediate and meaningful way,” says Donji Cullenbine, whose son took part in the study. She said enrolling on it was “one of the best choices “The glasses can provide a that I have ever made for him”. game-like environment to Using technology such as practise life skills without Google Glass to support being overwhelming” individuals with autism has been a promising area of research. The aim is to provide a game-like Social Responsiveness Scale, environment to practise life skills which is commonly used in without being overwhelming. autism research. But the idea has never been used The children’s scores on this outside the lab before. questionnaire fell by an average Dennis Wall at Stanford of 7.38 points during the study, University and his colleagues indicating a drop in the number have now shown that the effects of autistic traits. None of the work outside the lab. They gave participants’ scores rose. Six of 14 children with autism a system the 14 participants had large called Superpower Glass to try at enough declines in their scores to home for 10 weeks on average. move down one step in the rating The system comprises a Google of their autism classification (npj Glass headset and an Android app. Digital Medicine, doi.org/cstc). 10 | NewScientist | 11 August 2018

a mosquito-borne virus across a city

Julian Brown was one of the participants in the trial

The results should be interpreted with caution since the study lacked a control group, says Wall, but the findings are promising. His team is now completing a larger, randomised trial of the therapy. Cullenbine and her son Alex had previously used regular sessions of applied behavioural therapy with a therapist over many years, but Alex’s gaze avoidance remained a significant issue for him. This was associated with anxiety, especially with other children, who can be unpredictable. Cullenbine noticed a difference in Alex’s eye contact patterns within just two weeks of using Superpower Glass. “Previously, it would be two or three times a day,” she says. “Then I noticed I wasn’t counting the times he looked at me anymore.” She says this increase still holds true almost two years after the trial. Access to early interventions is crucial, says Deborah Riby at Durham University, UK. “I would also hope to see this intervention compared to other types of social skill and emotion recognition training packages so that we can see whether the benefits are specific to this intervention,” she says. ■

(Gates Open Research, doi.org/csr6). Scott O’Neill at Monash University in Australia and his colleagues infected Aedes aegypti mosquitoes with naturally occurring Wolbachia bacteria, which hamper the mosquitoes from transmitting the dengue virus. They released 4 million of the infected mosquitoes across Townsville over a two-year period. Once released, the infected mosquitoes bred with wild mosquitoes and passed on the Wolbachia bacteria to their offspring, so that these became worse at transmitting dengue too, says O’Neill. The Wolbachia bacteria pose no risk to humans, animals or the environment. A total of 11 countries, including Indonesia, Brazil and Vietnam, are now trialling Wolbachiainfected mosquitoes. These nations have higher rates of dengue than Australia, meaning modified mosquitoes may work less well. However, O’Neill says the preliminary results look positive. Although the exact mechanisms are still being unravelled, research suggests that Wolbachia prevents dengue transmission in two ways: it makes the mosquito immune system more resistant to the virus, and it makes it harder for the virus to extract nutrients from mosquito cells. Lab studies suggest that Wolbachia also blocks mosquito transmission of Zika and chikungunya viruses, but field studies are needed to confirm this. Alice Klein ■

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

Jake Buehler

CALL it small-dog syndrome. When small dogs urinate on objects on their walks, they seem to be using this opportunity to deceive, by aiming high to give the impression that their mark was left by a bigger animal. When male dogs spray urine, they are “scent marking”: laying down an odour-based message to other dogs that communicates health, sex and age. In this way, scent marking is considered an “honest signal”, relaying accurate information to potential competitors and mates. But when Betty McGuire at Cornell University in New York looked at how body size influenced scent marking, she and her team noticed a curious pattern. Small dogs urinated more frequently than larger dogs, and they were more likely to urinate towards vertical targets. “Small males seemed to make an extra effort to raise their leg

Lab-made lungs allow pigs to breathe easy IN A bioengineering breakthrough, lungs made in a lab have been implanted into pigs for the first time, enabling them to breathe normally. “I would argue this is the first time that a tissue-engineered organ has been implanted in a large animal and shown to survive and have any degree of function whatsoever,” says Laura Niklason at Yale University, who was not involved in the work. To make the lungs, Joan Nichols at the University of Texas Medical Branch at Galveston and her colleagues used growth hormones

high – some small males would almost topple over”, says McGuire. “So, we wondered whether small males try to exaggerate their body size by leaving high urine marks.” Her team filmed adult male dogs urinating on short walks to calculate the angle of their legs when raised. This was compared with the dogs’ height and mass. The team also measured the height of the urine marks on the chosen targets (Journal of Zoology, doi.org/cssz). Unsurprisingly, when the dogs raised their legs at a greater angle, the urine left higher traces on nearby surfaces. The team found that small dogs angled their legs proportionately higher when urinating than bigger dogs did, thereby marking higher than expected for their size. The point is probably to deceive competing males, says the team. “Direct social interactions with other dogs may be particularly

to encourage pig lung cells to grow into tissue, populating the protein skeleton of a pig lung with all its cells removed. The repopulated lungs were kept in a sealed chamber for 30 days, where they grew new blood vessels. Four of the organs were implanted into young pigs, which had each had one lung removed. The animals didn’t need drugs to suppress their immune systems, since the lungs were grown from their own cells, and their bodies gave no sign of rejecting the organs. By two weeks after surgery, Nichols’s team detected blood circulation in the engineered lungs, and measured similar tissue density as in a natural lung. The measurements showed that the lungs also had normal pressures and

LINDSAY MAIKO PFLUM/GETTY

Small dogs like to aim high

Urine for a surprise when you find out how big I am

risky for small dogs,” says McGuire, because they can’t measure up physically in one-onone competition with bigger dogs. This risk may be why small dogs seem to prefer scent marking, doing so more often than large dogs; it allows them to establish a presence without interacting with competitors directly.

The science of animal urination is a fast-moving field. In 2014, an Ig Nobel prize was awarded to researchers who discovered that mammals seem to prefer to urinate aligned north-south to Earth’s magnetic field. And in 2015, one was awarded for the discovery of the “universal law of urination” – the fact that all mammals that weigh more than 3 kilograms take about 21 seconds to empty their bladders. ■

volumes, although one pig developed a partial airway blockage that reduced lung expansion. Gene expression was also similar between the artificial and natural lungs (Science Translational Medicine, doi.org/csr7).

Although the team implanted the lungs, which became supported

As the animals grew, the number of cells in the bioengineered lungs increased and they spread to fill in

non-oxygenated blood from the

“This is the first time an engineered organ has functioned as a transplant in a large animal”

by the pigs’ blood vessels and enabled the animals to breathe, they didn’t connect the organs to the pulmonary artery. This blood vessel takes heart to the lungs, where it is infused with oxygen, and then carried around the body. Until bioengineered lungs have been hooked up to the pulmonary artery, we can’t know

any gaps created in the lung tissue,

how well they work. Nichols now wants to test the ability of the bioengineered lungs to

letting them fully support blood flow.

oxygenate blood from the pulmonary

Nichols’s team chose to do the test

artery. If successful, the hope is that

with pigs because the animals grow

we will one day be able to grow new

quickly and it would reveal whether

human lungs from our own cells. Chelsea Whyte ■

the lungs could grow with the body.

11 August 2018 | NewScientist | 13

NEWS & TECHNOLOGY Dark matter might be from another galaxy IT WAS recently revealed that our galaxy, the Milky Way, ate a so-called sausage galaxy about 10 billion years ago. Now it seems this meal might make finding dark matter ever harder. We can’t see dark matter directly because it is invisible, but we can track its gravitational pull by following the paths of nearby stars. Lina Necib at the California Institute of Technology and her colleagues used the biggest-ever map of stars and their velocities to do just that. IR STONE/GETTY

The velocity map showed a population of stars in our galaxy with weird, elongated orbits. Data on their composition revealed they have an

How the Maya met their end Michael Le Page

To find out how significant they were, geochemist Nicholas Evans at the University of Cambridge and his colleagues extracted ancient water trapped in the gypsum and analysed its isotopic ratios. Water molecules that contain, say, an oxygen-17 atom instead of the more common oxygen-16 are heavier and less like to evaporate. Heavier water molecules therefore accumulate

UP TO around AD 750, the Mayan civilisation was thriving. Dozens of monuments were being built every year in what is now Mexico and Central America. By AD 900, however, such building ceased altogether and some cities in the southern lowlands were abandoned. What happened? One idea is that a prolonged drought was to blame, and now “It doesn’t take a dramatic we have the best evidence yet change in climate to cause that this was the case. Analysis enormous problems. This of “fossil water” shows that there was half as much rain as usual is a lesson for humanity” between AD 800 and 1000, and that at times during this period in the lake during times of low there was 70 per cent less rainfall. rainfall and high evaporation. During prolonged dry periods, Although isotopic analysis gypsum may precipitate out of has been around for decades, lake waters and be deposited in Evans’s team has developed a sediments. The presence of such method that allows simultaneous deposits in Lake Chichancanab in measurement of the levels of all Mexico provided the first evidence the different isotopes of oxygen of prolonged droughts around and hydrogen. This reveals a the time of the Mayan decline. wealth of information: rainfall, But their severity was unknown. water temperature and even 14 | NewScientist | 11 August 2018

intermediate iron content compared

Chichén Itzá is among the best preserved Mayan sites

humidity levels (Science, DOI: 10.1126/science.aas9871). “We get the full climate picture,” says Evans, who is using the technique to study past climate in many other places and says it could even reveal what Mars used to be like. While this work cannot prove cause and effect, there is growing evidence from around the world that many periods of upheaval and war coincided with climate change. The drought could have had a domino effect, says Evans, with food shortages leading to unrest, warfare and political disintegration, and the eventual downfall of the Maya’s ruling elite. “The changes [in rainfall] were considerable, but not overly dramatic,” says Eelco Rohling of the Australian National University, who has also studied how rainfall changed at this time. “In other words, they are a good illustration that no dramatic changes in climate are needed to cause enormous problems. This truly is the lesson humanity should learn for our future.” ■

with the Milky Way’s two main star populations. A star’s metal content is dictated by its age, so these stars are younger than the halo stars, which come from early in the Milky Way’s history, but older than the ones in the galaxy’s disc, which were born later on. This indicates that these stars, and their dark matter, weren’t born in our galaxy, but were slurped up in a galactic merger. They are what is left of the sausage galaxy, so named because of the stretched-out orbits of its stars. “This one particular merger is dominating quite a bit of the structure and quite a bit of the mass,” says Necib. About 65 per cent of the stars in the immediate area around the sun that weren’t born here are from the sausage galaxy. Her team is working to confirm what proportion of the dark matter came from the merger, but she says it is probably also about two-thirds (arxiv.org/ abs/1807.02519). These stars are moving slower than everything else, which could make their dark matter harder to detect. “Higher-velocity dark matter tends to be easier to see,” says Matthew Buckley at Rutgers University in New Jersey. “It’s got more kinetic energy, so it makes a bigger bang when it enters your detector.” Leah Crane ■

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Join an exclusive trip packed with art, architecture and the ideas that laid the foundations of modern thinking. Let art and architecture expert Andrew Spira guide you around three stunning Italian cities. Eat delicious food, drink local wine and enjoy evening talks by Andrew and New Scientist ‘s editor-at-large Jeremy Webb. Visit Pisa with its Leaning Tower and Cathedral, where Galileo is said to have first pondered pendulums.

In Florence, admire Brunelleschi’s daring dome atop the cathedral and his Old Sacristy at San Lorenzo with its Ptolemaic planetarium. Enjoy elaborate collections at the Pitti Palace and Speculo Museum, and catch an early example of artistic perspective in the Brancacci Chapel. Visit much under-rated Bologna. Discover its Anatomical Theatre and the science museum at Palazzo Poggi. And don’t forget to sample its world-renowned cuisine. Our celebration of culture includes four-star hotels throughout.

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IN BRIEF Toxic millipedes are medicine to lemurs

AI spots vines that stop the rot ruining the wine

Steinhage and his colleagues at the University of Bonn and the Julius Kühn Institute in Germany created a mobile lab to automate the process. They place grapes under a light and take a series of

ARTIFICIAL intelligence and photography are together helping winemakers keep their grapes free of disease. The fungus Botrytis cinerea affects grapes around the

high-resolution photos to pick up patterns of scattered light – including the diffuse reflections given off by the roughness of the wax. The pictures are analysed by two AI algorithms: one singles out the grape; the other determines the distribution of waxiness over its surface. The researchers trained the AIs on 90 images with

world. While it can shrivel and sweeten grapes, which is welcomed in sweet wines like Sauternes, it also causes widespread losses of harvest in many wine regions. Pesticides are the most common defence, but an environmentally friendly alternative is to cultivate grapes with a natural resilience – those with a waxier surface. However, manually checking the wax coverage of grapes is laborious and subject to human error. So Volker

more than 6.5 million labelled pixels. They then took 180 images of six grape varieties to train and test the system. In just a few seconds, it could detect the wax distribution on a grape with an accuracy of about 95 per cent (arxiv.org/abs/1807.07343).

Clue to cystic fibrosis found in new cell A COMPLETELY new type of cell has been discovered in the human airway, and it may have a central role in the common genetic condition cystic fibrosis. Aron Jaffe at pharmaceutical company Novartis and his colleagues discovered the cell by analysing gene activity in epithelial cells – which line membranes – taken from human lungs and the tracheas of mice.

They found a specialised kind of epithelial cell, which they named a pulmonary ionocyte. Its gene activity is similar to ionocytes in frog skin and fish gills, which move ions to regulate the pH of the liquid layer next to them. These new cells make up less than 2 per cent of all those in the airway epithelium, but they seem to be the main cell type where the

gene involved in cystic fibrosis acts (Nature, doi.org/gdwsj7). This CFTR gene makes a protein that lets certain ions move in or out of cells. A variety of mutations can disable this gene or its protein, causing thick mucus and bacteria to accumulate in the lungs of people with cystic fibrosis. Knowing where CFTR is active is an important step on the road towards new cystic fibrosis therapies, says Jaffe.

LEMURS have been spotted chewing on toxic millipedes then rubbing them over their genitals and anuses. The bizarre behaviour may be a way to combat parasites that would otherwise set up home in the lemurs’ guts (Primates, doi.org/csp5). Louise Peckre of the German Primate Center in Göttingen was observing red-fronted lemurs in a forest in central Madagascar, which are exposed to a range of gastrointestinal parasites. She watched as an adult female rubbed her tail, genitals and anal region with a toxic millipede she was holding. The lemur then gave the millipede a quick chew before rubbing it on herself again. Over the day, five other lemurs did the same. Peckre thinks they were self-medicating. Smothering their anal regions with millipede toxins might kill parasites, helping lemurs either treat an infection or avoid contracting one.

Star has facelift to look much younger A DISTANT star has just undergone an explosive facelift. Martín Guerrero at the Institute of Astrophysics of Andalusia in Spain and his colleagues observed a planetary nebula: a cloud of dust and gas around an ageing star. Strangely, the cloud’s centre was cooler than the edge that was furthest from the star (Nature Astronomy, doi.org/csrx). The researchers realised they were witnessing the aftermath of a “born-again event”, in which a star gets hot enough to fuse helium into carbon and expel it in a high-speed wave. This makes the star look cooler and dimmer, and thus younger. They had glimpsed the nebula just after a hot wave had passed through it, which is why the outer part was hotter. 11 August 2018 | NewScientist | 17

IN BRIEF

EACH line of the Hong Kong subway system has its own bacterial community, but commuters mix species across the network every day, according to a new study. Gianni Panagiotou at the University of Hong Kong and his team asked volunteers to enter the city’s subway with clean hands and ride for 30 minutes while holding the handrails, then swabbed their palms. Analysing the swabs, they found that the majority of microbes the volunteers picked up were common skin bacteria. In the morning rush hour, 140 species were detected, but by evening, many of those were no longer detectable and just 48 species covered the entire system. The mix of microbes seen on each line at the start of the day seems to be determined by where it begins. The highest number of soil species and antibiotic-resistant bacteria were found on an uptown line and the line linked to mainland China. The resistance genes carried by

ALAN GRAF/CULTURA RM EXCLUSIVE/GETTY

these bacteria were mostly against antibiotic drugs used to treat people, but the team also detected resistance to tetracycline, which is commonly added to pig feed. These genes were mostly on the northern train lines at the start of the day, but had dispersed throughout the city by evening (Cell Reports, doi.org/csrt).

18 | NewScientist | 11 August 2018

A venomous snake that is doubly deadly THE fangs of the Amazon puffing snake are a double-edged sword. This South American tree snake has developed a venom with toxins that target different prey – one for killing small mammals, and another that targets birds and lizards. “These Amazon puffing snakes are not very good constrictors, so they’re at a disadvantage,” says Stephen Mackessy at the University of Northern Colorado, who studied the venom produced by Spilotes sulphureus. He has found that the snakes’

venom gives them a different kind of advantage. Mackessy and his team extracted the venom from three of the snakes – no easy feat when they can grow to 2.7 metres in length and their venom flows slowly. The researchers analysed the toxins present and tested the dose that house geckos and mice could withstand. They found sulditoxin, which is highly toxic to lizards and birds, but not to mammals even when the dose is 22 times higher than what would be delivered by a bite. They also found sulmotoxin 1,

which works the other way round and is lethal to mammals but not birds or lizards (Proceedings of the Royal Society B, doi.org/css9). While other snakes have developed prey-specific neurotoxins in their venom, this is the first time such a twofanged tactic has been shown, says Bryan Fry at the University of Queensland in Australia. Over time, this snake’s prey may have been evolving resistance to its venom. In turn, the snake is evolving new toxins, says Mackessy. STEVE CRAFT/GETTY

Resistant bacteria take the subway

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Stonehenge was a Welsh burial site SOME of the bodies buried at Stonehenge in southern England may have come from hundreds of kilometres away in Wales. It had been assumed that the individuals whose cremated remains were found at the site were locals. Now a new technique for analysing such remains has found that some came from the same area as the first standing stones at the site – west Wales. Strontium isotopic analysis can tell what foods someone was mainly eating in the last decade before they died. Plants have different levels of strontium depending on the bedrock where they grow, and this can be read in the bones of those who eat them. It had been thought that cremation destroyed isotope structures. But Christophe Snoeck and his team from the Free University of Brussels (VUB) in Belgium found that intense heating effectively “seals in” some isotopic signatures (Scientific Reports, doi.org/csr2). Using their new technique on 25 of the cremated individuals, the team found at least 10 of them had strontium levels consistent with an area of western Britain that includes Wales.

Lasers used to bring up the bodies FINDING bodies buried in unmarked graves can be extremely difficult, but lasers might be able to help. To find out, Katie Corcoran at Oak Ridge National Laboratory in Tennessee and her colleagues dug shallow pits and buried corpses of individuals who had donated their bodies for research. They used quick pulses of laser light, or lidar, to make a 3D scan of the area before the bodies were buried, and then scanned again one day later and then after four months and 21 months. The first of these scans revealed that the grave surface became

elevated by a few centimetres shortly after burial. It then shrank back down again between the second and third scans (Forensic Science International, doi.org/csp6). The decrease in elevation was probably caused by the bodies decomposing in the first few months, creating more room for the soil to settle, say the researchers. The results show that investigators could narrow down possible locations in the months after a grave is dug by taking two or more lidar scans, which can be done from the ground or even an aircraft.

INSIGHT DNA CRIME-SOLVING

Family-tree forensics Police are using consumer DNA services to trace criminals via their relatives. Is this a genetic step too far, asks Chelsea Whyte

PAUL KITAGAKI JR./SACRAMENTO BEE/TNS VIA GETTY IMAGES

Joseph DeAngelo is awaiting trial on murder charges

THE Golden State Killer terrorised California with a spree of murders, rapes and burglaries between 1974 and 1986. Then the killer went quiet, and the case went cold. But on 24 April 2018, the Sacramento Police Department arrested Joseph James DeAngelo, an ex-police officer, in connection with the killings. His DNA led them to him – and sparked a growing ethical debate. The detectives identified DeAngelo after uploading DNA evidence from a 1980 Golden State Killer rape case to GEDmatch, a website that lets people trace lost relatives by adding genetic information to a genealogy database. Among the 1 million users of the service, the detectives found several relatives 20 | NewScientist | 11 August 2018

of the killer. All were third The team hunting the Golden cousins, so shared at least one set State Killer is one of a number of great-great-grandparents with of groups turning to genetic the Golden State Killer. Building ancestry to solve mysteries. out the family tree, they used the Colleen Fitzpatrick at the nonkiller’s location and approximate profit DNA Doe Project has been age to narrow the suspect list. using GEDmatch to find relatives Although 1 million sets of DNA of unidentified victims. “We might seem too small a sample to didn’t know they were doing find one person – considering the US population is 325 million – the “Every year has been a record year for people investigators only needed a little uploading genetic data luck. Yaniv Erlich of genetic to consumer sites” ancestry company MyHeritage and his colleagues calculate that a database with genetic info on just the same thing we were until we 5 million people would be large saw the news,” she says. “It was enough to find a third cousin an idea whose time had come.” match for almost any white person Parabon NanoLabs, a in the US, because most people on biotechnology firm in Virginia, consumer genetic databases fall also joined the fray after DeAngelo into this ethnic group. was arrested.

All these groups use units called centimorgans to measure the similarity between two strings of DNA. One centimorgan is on average 1 million base pairs – the linked As and Ts, and Cs and Gs of our genetic code. The more closely related two people are, the more centimorgans of DNA match up (see graphic, right). Genetics firm 23andMe has found that most people have about 190 third cousins. “You take a random person and this person becomes a beacon that illuminates, say, 300 people – their third, second and first cousins,” says Erlich. “In a population of 250 million Caucasians, it doesn’t take so much to illuminate everyone.” In other words, genetic information relating to the majority of the US population is on these databases, even though few have signed up. The legal ramifications of this are only now becoming clear. Neither privacy law nor property law is well-adapted to dealing with genetic data, which is unavoidably shared among many people, says Natalie Ram at the University of Baltimore, Maryland. You could treat it like property held by married couples, she says – one partner can’t give away shared property without the other person’s permission. But genetic information is so widely spread that it would be impossible to coordinate consent from everyone who shares your DNA. The situation is evolving, but law enforcement won’t want to give up this powerful tool. Police databases built with DNA analysis hold only about 20 genetic markers. With genotyping for

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genealogy, hundreds of thousands of markers are put to use, says CeCe Moore, a genetic genealogist at Parabon Nanolabs, who has helped solve seven cases since DeAngelo was arrested. And not just historical cases (see “The genetic case files”, below). “After the Golden State Killer case, every law enforcement agency sat up and took notice,” she says. “I still have a long list of cases waiting for my attention.”

Ethical issues Consumer genetics services have been available for some time, so why are police just starting to exploit them? Before this year, GEDmatch wasn’t large enough to find distant relatives, Moore says, and it is the only database that allows access for this kind of work. Firms like 23andMe and Ancestry. com – others big enough to run such a search – don’t allow police to upload forensic profiles. Curtis Rogers, co-founder of GEDmatch, says that the use of his database in the Golden State Killer case came as a surprise. “I spent two weeks not sleeping, trying to figure out the ethics of this situation. Do we ensure that the privacy of all our users is protected? Or do we go after murderers who make Jack the

Ripper sound like a choir boy?” In the end, he says, GEDmatch doesn’t have the legal resources to prevent the site being used this way. “We could have published a statement that says we require a court order for police to use our site, but it’s only words,” he says. “They could go ahead and do it, and they probably would.” Since the use of GEDmatch in the Golden State Killer case came to light, the website has updated its terms of service to inform users that their data could be used in a similar fashion. And last week, firms including 23andMe and Ancestry.com released new guidelines on how they will respond to law enforcement requests for data. “Some of my colleagues in genetic genealogy don’t approve of my choice to work with law enforcement,” Moore says. She says she had been approached to do such work before, but waited until GEDmatch updated its rules. “I don’t want to use the DNA of anyone who doesn’t want it used in these cases,” she says. Despite uniquely identifying you, DNA records are considered in US law to be de-identified information that can be given to the police without a court order. And law enforcers are likely to want to gather DNA from other

The closer a relative is to you, the more closely your DNA will match up with theirs Parent

Min

Full siblings Half-sibling, grandparent, aunt/uncle

First cousin, great-grandparent, half aunt/uncle, great aunt/uncle First cousin once removed, half irst cousin, half great aunt/uncle Second cousin, irst cousin twice removed, half irst cousin once removed Second cousin once removed, half second cousin, irst cousin thrice removed, half irst cousin twice removed Third cousin, second cousin twice removed Third cousin once removed, second cousin thrice removed

0

1000

2000

3000

Length of matching sequences, measured in centimorgans of DNA

sources, given the success with GEDmatch. Some US states allow DNA samples to be taken from anyone who is arrested, even if they are not charged with a crime. Taking part in a research trial could also mean signing away your genetic data. And even if you don’t do these things, someone you are related to might. “Every year has been a record year for people uploading genetic data to these consumer sites. It goes up exponentially,” says Erlich. The consequences of familial

THE GENETIC CASE FILES SUSPECTED BROTHERS

EXECUTED KILLER

NOT-SO-COLD CASE

In 1986, 12-year-old Michella Welch went missing in Tacoma, Washington. Police found her body in a ravine near a local park. She had been sexually assaulted and murdered.

Virginia Freeman, a Texas real estate agent, was found dead in 1981 behind a home she was selling. She had been hit with a blunt object, stabbed and strangled. Detectives found DNA under her fingernails, but the case went unsolved. This year, a DNA profile generated from the sample pointed to the unknown suspect’s second cousins and great grandparents, which led to the identification of James Otto Earhart as the killer. Earhart was executed in 1999 for the kidnapping and murder of a 9-year-old girl. His body has been exhumed to confirm the match.

Most cases solved in the wake of the Golden State Killer arrest are decades old (see main story), but Utah police have now used genetic genealogy to track down a suspect

The police took evidence, but couldn’t solve the case. In May 2018, a profile from the unknown suspect’s DNA led to a relative of the suspect. He was the half cousin of two brothers. Police followed one of them, Gary Hartman, into a diner and picked up a napkin he had used. His DNA matched the sample from the body, and police charged Hartman with murder and rape in the first degree. He has pleaded not guilty.

Max

in a recent crime. In April 2018, a 79-year-old woman named Carla Brooks reported that a man broke into her home while she was asleep and sexually assaulted her. Police used a DNA sample and genetic genealogy to find Spencer Glen Monnett, a 31-year-old Utah man, who was charged with burglary, rape, sexual battery and assault. He was arrested on 28 July, just 14 weeks after the crime was committed.

databases stretch beyond criminal investigations. Undercover operatives could be revealed, and egg and sperm donors could be unmasked without their knowledge or consent. Of course, there are upsides. Holocaust survivors and adopted people have tracked down longlost relatives, and families have been given answers about deceased loved ones. We now need to decide where to draw the line. “If the person arrested is the Golden State Killer, bringing him to justice is a significant victory,” says Ram, but a wish to solve crime cannot override privacy, she adds. If police push the use of genetic data too far, there may be a backlash against genetic research and testing. “I come down on the side of the families of the victims,” Moore says. “This could also work as a deterrent. If we stop one crime, that would be worth it.” She says people can still choose to use a consumer genetics company that doesn’t share data with police. But none of us can avoid it for long. If a distant relative puts their DNA online, yours is out there too, whether you like it or not. Trying to go back and change that now is futile, Fitzpatrick says. ■ 11 August 2018 | NewScientist | 21

COMMENT

A vote against deepfakes AI-generated hoax videos won’t wreck democracy this year as some are predicting, says Tim Hwang THERE is no doubt that recent demonstrations of believable fakes generated by machine learning are striking. From uncanny simulated voices to fabricated videos of political leaders, it is natural to worry that these techniques will make it easier to manipulate political discourse and public opinion. But it is worth taking a step back. Just because a capability exists does not mean that it will be widely used, or make a serious impact. There are good reasons to believe that – for the near future – “deepfakes” enabled by artificial intelligence will see limited use, and have limited impact. To that end, I’m taking part in a friendly public wager and betting that by the end of 2018, we will not have seen a political hoax generated by machine learning get more than 2 million views before being discovered. Given

that this is a year in which US voters go to the polls again for their mid-term elections – when we might expect disinformation campaigns to be likely – why do I think I’m backing the right horse? The economics are important: state and non-state actors using online propaganda want to achieve the most influence at the lowest cost. We need to recognise that rudimentary techniques can already have a big influence on public discourse. Numerous incidents attest to the fact that simply reusing an old video and asserting that it is something that it is not can be sufficient to fool many people. A crude Photoshop job can spread disinformation. At the same time, AI remains a relatively costly tool for generating hoaxes. The current breakthroughs in AI rely on two major inputs – large datasets and computational power – both of

What’s the beef? The term “lab grown meat” is already riling cattle farmers, says Sasha Chapman A DUTCH start-up announces it has raised $8.8 million to commercialise its lab-grown burger. Meanwhile, the US meat industry gears up for a scuffle with the new kids on the block. Mark Post, CEO of Mosa Meat, predicts he can get the company’s burger into restaurants at $10 a pop by 2021. This is substantially 22 | NewScientist | 11 August 2018

what this will mean for them. While Post was trumpeting his plans, meat industry lobbyists were in Washington DC to prepare for battle over the labelling and regulation of lab-grown meat, particularly what it calls itself. While the term “lab-grown meat” has taken hold, some advocates prefer “clean meat” because they see it as a way of dispensing with slaughter and the degradation of our environment to produce meat. Detractors say

cheaper than the world’s first cultured beef patty, which cost $300,000 when Post unveiled it in 2013. This bodes well for the economic viability and rapid development of cellular agriculture: the culturing of meat, “When people first used the word meat, they fish and dairy products in vats. simply meant food as Which is why conventional opposed to drink” farmers are now worrying about

lab-grown meat is “fake”. The US Cattlemen’s Association wants the US Department of Agriculture to define meat as “tissue or flesh of animals that have been harvested in the traditional manner” – as if an animal must die to make a burger authentic. Those who insist on limiting the definition of meat are hoping to continue a trend. Historian Benjamin Wurgaft, writing a book about cultured meat, points out the definition has narrowed over time. When people first used the word meat, they simply meant food (as opposed to drink). It wasn’t until the 1300s that it began to refer to animal flesh.

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Tim Hwang is a writer and researcher, and director of the Harvard-MIT Ethics and Governance of AI Initiative

And the definition has arguably narrowed again – today for a lot of people it equates to the animal proteins that dominate the food system: poultry, beef and pork. Maybe the debate over what to call flesh grown in a vat will upend that trend. Maybe it will narrow it further. What is certain is that a war of words lies ahead. Let’s hope that conversation also allows a broader discussion of a growing reliance on meat – and whether any technology can sustain that on a planet of limited resources. ■ Sasha Chapman is a Canadian writer focused on environmental and health implications of the global food industry

ANALYSIS 3D-printed firearms

ROBERT CLARK/NATIONAL GEOGRAPHIC/GETTY

which can be expensive to acquire. Moreover, the techniques behind the more impressive demonstrations of AI-driven fabrication, known as generative adversarial networks, are famously temperamental. This all suggests that, in the near term, AI-constructed fakes will be inferior to the existing arsenal of propaganda tools. As a result, researchers have more time to create effective methods for detecting this type of fakery. It also enables society to adjust to the knowledge that everyday video can be faked in this way, and to be on guard before widespread deployment. Ultimately, it is possible that deepfakes are a diversion from more crucial questions. Or we may eventually see AI-driven hoaxes become an attractive option for technology-minded propagandists. But it will be the draw of the underlying narratives pushed by these fakes that determine their influence. A better understanding of the behavioural factors driving belief in hoaxes will be the only way to avoid playing an unwinnable game of technological whack-a-mole. ■

The real US gun crisis is being overlooked Frank Swain

and quietly gave permission for the files to go online again from 1 August. Eight US states in turn sued the Department of State and got a temporary restraining order issued to block the release of the files. A hearing next week will decide what happens next. Amid all this legal wrangling, a key question has gone unanswered: are these weapons actually a threat? The prospect of roving gangs armed with 3D-printed guns is slim. The Liberator is a clunky and ineffective weapon that can only be fired a few times before the plastic barrel splits. Equally,

LAW-MAKERS in the US are fighting to keep blueprints for 3D-printed guns off the internet – but how worried should we be about untraceable plastic firearms? In 2013, law student Cody Wilson unveiled the Liberator, a plastic handgun produced on a 3D printer that could fire conventional ammunition. He posted the files online so that anybody could download them and, in theory, print their own pistol. He later added a second design that helps people to mill a rifle part called a lower receiver from a block of aluminium. These parts are controlled “The fate of 3D-printed firearms is a distraction under US gun regulations and carry from the US’s much larger identifying serial numbers. gun public health crisis” By releasing plans for untraceable weapons that could be produced at home, Wilson was making effective building your own gun is not illegal in gun regulation impossible. The US the US, and anyone with the required Department of State told Wilson to skills is free to create their own lower remove the files from the internet. receiver on a milling machine. They had already been downloaded Although untraceable firearms more than 100,000 times. sound particularly scary, the US is Wilson sued the Department of already full of them. And regulations State in response. It relented last designed to enforce US gun rights month, following a lengthy legal battle, prevent the government from creating

a searchable, computerised database of gun store sales. Instead, the records are kept on paper and microfilm, which must be painstakingly searched by hand. In many states, private sales are unmonitored. Behind the hysterics over new technology, the crux of the debate lies in whether the government should control access to firearms. As a risk to citizens, the Liberator is underwhelming; it poses a much greater threat to the authority of the US government. An age of easily shareable digital files and reliable fabrication offers resistance to what Wilson called “the collectivisation of manufacture”, putting it outside the control of authorities. Ultimately, the fate of 3D-printed firearms is a distraction from the US’s much larger gun problem: the public health crisis of the tens of thousands of people who die each year as a result of gun violence. Since 2013, when Wilson first released his plans for the Liberator, no one has been killed by a 3D-printed gun. According to the Gun Violence Archive, an organisation that launched in the same year to collate statistics on gun violence, 65,310 people in the US have been killed by guns since 2014. What’s more, that doesn’t include the roughly 22,000 gun suicides that take place in the US each year. The US has a gun problem – 3D printing is a distraction. ■ 11 August 2018 | NewScientist | 23

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APERTURE

26 | NewScientist | 11 August 2018

What Katy did YOU never know what you will find in the rainforests of Panama’s Cocobolo Nature Reserve. Nestled in a thin forest corridor that connects habitats in North and South America, it is a crucial pit stop for migratory species and holds a huge array of wildlife, including jaguars, snakes and hummingbirds. It also hosts this master of disguise: a leaf-mimic katydid (Cycloptera sp.). This insect is just 5 centimetres from its head to the tip of its abdomen, but a bit over double that if you include the long antennae, says photographer Clay Bolt. Katydids don’t stop at mimicking healthy leaves – they have perfected realistically tattered foliage, complete with speckles of discolouration, holes and sections at the fringes that look as though they are dying or diseased. This helps them avoid predators like monkeys, which comb through the vegetation in search of snacks. Katydids are hard to spot during the day, when they stand stock still. It is only at night, when they slowly munch on leaves, that the gentle wave of those antennae might give them away. To get the natural look of this shot, Bolt had to compensate for the deep shadows of the rainforest. First, he took an exposure of the background. Then he used a soft diffuser to highlight the insect. “I don’t want the viewer to think about flash or any ‘hand of man’,” he says. “I  want them to mentally step into the scene and feel awe about this amazing creature.”

Chris Simms

Photographer Clay Bolt claybolt.photoshelter.com

11 August 2018 | NewScientist | 27

SAM PEET

28 | NewScientist | 11 August 2018

COVER STORY

THE ALLERGY

EPIDEMIC MYTHS about allergies abound. Allergies are psychosomatic. Being too clean is causing allergies. Honey can cure hay fever… None of these statements is true. What is true is that possibly a quarter of us are alicted by some form of allergy – and that number is on the rise. You might even be affected by one without realising. So how can we best deal with the allergy explosion? Penny Sarchet brings you the advice that’s not to be sneezed at.

WHAT ARE ALLERGIES ANYWAY? If your summer months are blighted by congestion, sneezing and a runny nose, you might think your immune system has gone into overdrive, or that it is especially good at its job. But unfortunately it’s not that simple. Allergies are caused by the immune system mistakenly reacting to certain innocuous molecules from the outside world. These can be part of anything from cat skin to certain foods (see “The most common allergies”, overleaf). Any molecule capable of doing this is called an allergen. Although allergens pose no real danger to our bodies, their structures are recognised as a threat by some people’s antibodies – immune proteins on the lookout for harmful invaders. Allergies involve a special class of antibodies called immunoglobulin E (IgE). Different IgE antibodies detect different allergens. When this happens, the antibodies trigger immune cells to release histamine and other inflammatory chemicals, leading to those nasty symptoms, which under normal circumstances would be a useful defence against invading organisms. This is a highly primed defence mechanism. IgE antibodies bind to immune cells about 1000 times more tightly than any other class of antibody. This means they are usually already attached to an immune cell, and the whole system is ready to respond as soon as an allergen is detected. This happens in seconds to minutes, while other branches

of the immune system take days to respond to a cold virus, for example. “It really is a remarkable system,” says Brian Sutton of King’s College London. One explanation for the sensitivity of the IgE arm of our immune system is that it evolved to detect and eject what was once a common, highly aggressive threat: large, invading organisms burrowing into our skin, airways or guts. In the absence of such parasites in modern, Western lifestyles, the IgE system seems to have begun misfiring, targeting harmless chemical structures instead. The system is more amped up in some people than others. “I’m not aware that I’m allergic to anything,” says Sutton, so the understanding is that he has low levels of IgE. “But some people will have 10 times, even 1000 times the level of IgE that I have,” he says. How much you have is partly down to genetics. It is possible that people who are more prone to allergies would have been better at detecting and ejecting parasites back in our evolutionary past. But being particularly prone to allergies doesn’t mean your immune system is powerful or overly active in general. You are just as likely to succumb to infections as others and there is no strong evidence that allergies make you more likely to develop autoimmune disorders, in which the immune system starts attacking the body. 11 August 2018 | NewScientist | 29

THE MOST COMMON ALLERGIES

ARE ALLERGIES BECOMING MORE COMMON?

Food

With some schools and airlines banning nuts, it might feel like we are entering an age of allergy hysteria. But it’s not just a symptom of helicopter parenting or heightened vigilance – allergies really are on the up. Hay fever, which is pollen allergy, was first described in 1870, but allergies were rare until the mid-20th century. The first rise was seen in childhood asthma, in which allergens or irritants cause the airways to tighten and become inflamed. From 1960 to 1990, childhood asthma rose to epidemic proportions in developed nations, followed by an increase in hay fever. By 1991, the number of family doctor consultations for asthma in the UK had quadrupled in only 20 years, and appointments for conditions such as pollen and dust allergy more than doubled. This rise in respiratory allergies was followed by a second tide. As asthma and hay fever began to stabilise in the 1990s and 2000s, food allergies in children shot up, increasing by 50 per cent in the US in just 12 years. “We believe asthma and allergies now affect about 25 per cent of the population,” says Syed Hasan Arshad at the University of Southampton, UK. Prior to 1970, around 10 per cent of people were thought to experience hay fever in rich nations. Studies now suggest it affects as many as 30 per cent of adults and 40 per cent of children. Around 7 per cent of children in the UK and similarly developed countries now have food allergies. It is tempting to think that these rises might be down to increased awareness and people going to see their doctor about these problems. But studies comparing different generations show this is not the case. And peanut allergies, for example, can be so severe it seems unlikely that doctors simply failed to notice them in the past. In fact, many more people may be living with allergies without realising. One study of a group of teenagers and adults in Copenhagen, Denmark, found that half the asthmatics in the group were undiagnosed and not receiving treatment. Rhinitis – hay fever-like symptoms that can also be triggered by dust mites, pets and mould – had not been diagnosed in a third of those who had it. Rapidly developing countries are now beginning to show similar increases in

There are many kinds of food allergies, but milk and egg allergies are the most prevalent type among young children in the US. People can also be allergic to peanuts, tree nuts, soy, fish or shellfish. Some are allergic to wheat, but there is no such thing as a gluten allergy. Coeliac disease, an autoimmune disorder triggered by the gluten found in cereal grains, is not an allergy.

Insects Stinging insects such as bees, wasps and hornets inject venom that most people quickly recover from, but it can provoke life-threatening allergic reactions in some.

Pollen Hay fever, or seasonal allergic rhinitis, is one of the most widespread allergies. It is usually caused by plants that don’t use animal pollinators to reproduce, instead releasing large amounts of pollen into the air.

Pets Allergies to furry animals are especially common among people who have other allergies or asthma. Pet hair itself is not an allergen, but it can carry urine, saliva and dander (flakes of dead skin), all of which can provoke allergic reactions. No cat or dog is truly hypoallergenic.

Household pests House dust mites and cockroaches produce waste that can trigger asthma and allergies. These pests are thought to be two of the most common causes of year-round allergic symptoms.

Latex Around 1 per cent of people in the US experience an allergic response to the latex protein. Healthcare workers and people who had a lot of medical care as children are particularly susceptible.

Mould There are many types of fungal moulds, but only a handful cause allergic reactions. When mould spores get into the nose and lungs, they can cause hay fever-like symptoms and asthma. 30 | NewScientist | 11 August 2018

Yet another warning? It’s not just paranoia – allergies, especially to food, are on the rise

allergies, particularly China. Between 1990 and 2011, asthma rates in Shanghai among 3 to 7-year-olds rose from 2 to 10 per cent. We still don’t know what has caused this rise in allergies, but there are clues (see right). Most obvious is how much Western lifestyles changed in the 20th century.

FACT PARASITES CAN GIVE YOU A MEAT ALLERGY A sugar carried by the Lone Star tick, found in North America, can sensitise people to mammal meat containing the same sugar, causing an allergy to red meat.

WHAT’S BEHINDTHE RISE IN ALLERGIES? Cleanliness is next to godliness, as they say, so for those who are a little less fastidious, the idea that dirt could protect from allergies might have a certain appeal. First proposed in 1989 by epidemiologist David Strachan, the thinking behind this “hygiene hypothesis” was that modern life has become more hygienic, leading children to catch fewer infections. This somehow predisposes them to develop allergies, perhaps because their immune systems have been incorrectly trained. If so, allergies are the price people in developed nations pay for massively reduced infant mortality. It is an idea that caught hold with the public, but it doesn’t fully add up. We now know that childhood infections don’t seem to make you any less likely to develop allergies. And major cities like London and New York had largely cleaned up their acts by 1920 – long before the

idea was put forward. Water chlorination and separate sewage systems made cholera and typhoid infections rare. And if clean living is to blame for allergies, it doesn’t make sense that it took 40 years for asthma to begin to rise. Since 1960, developed countries have seen only minor changes in hygiene, so what prompted the sudden and recent surge in food allergies? What we do know is that older siblings are more likely to get some allergies than younger siblings, and that children who grow up in big families or on farms are less likely to develop them. Rather than cleanliness in the home or catching infections, the key factors seem to be spending time with other children and being outdoors in early life – probably because this maximises the range of microbes we meet as infants. As people in the West moved towards spending more of life indoors and in

urbanised environments, as is now happening in nations like China, they may have lost contact with particular microbes that have helped hone the human immune system for millennia. This is known as the “old friends” hypothesis. How such friendly microbes may help prevent our IgE system from misfiring is still largely unclear. But we are beginning to understand that the different bugs living in our bodies can affect many aspects of our health. It is possible that some of them help quieten down elements of the immune system, preventing any overreaction. You are unlikely to restore these missing microbes simply by neglecting your personal hygiene, however. And by the time you are an adult, there may be little you can do to shift your microbiome – it is probably too late to up sticks and move to a farm.

PAT CANOVA / ALAMY

CAN EXPOSURE CURE MY ALLERGY? If you have ever heard someone claim they have cured their hay fever by spending time outdoors or that a daily serving of honey – which contains pollen grains – has built up their immunity, don’t fall for it. “There’s not much evidence for that,” says Arshad. Similarly, forcing yourself to eat peanuts if you are allergic to them is a bad idea, as is living with a pet in the hope that one day you will get along fine. The idea is grounded in sensible science, though. Clinical injections of small, increasing doses of an allergen can desensitise the immune system to some allergies. When it is administered over several years, there is good evidence that this treatment can work for allergies such as bee and wasp stings, as well as nasal inflammation caused by grass pollen, tree pollen or house dust mites, says Graham Roberts of the University of Southampton, UK. The treatment, often known as allergen immunotherapy or “allergy shots”, seems to gradually build up the amount of exposure the immune system can handle. But as the technique can prompt swelling or itching near the injection site, and in some cases anaphylaxis, breathing problems and collapse, it should be administered by a clinician at a hospital. Some experimental peanut immunotherapies have had good results

in children, providing lasting effects, but patients need to keep eating peanuts to maintain the protection, says Roberts. Immunotherapy seems to work well for cat allergies too, but is less effective for dog allergies. However, this isn’t something you can mimic yourself by frolicking in the grass or buying a cat – in fact, doing so is likely to make the problem worse.

FACT ALCOHOL CAN WORSEN YOUR ALLERGIES Alcoholic drinks can contain histamine, a chemical released as part of the body’s immune response. This can amplify allergic reactions and boost hay fever symptoms, particularly in women.

11 August 2018 | NewScientist | 31

ARE WOMEN MORE ALLERGY-PRONE?

CAN YOU GROW INTO AND OUT OF ALLERGIES?

In adult life, women are certainly more likely than men to report having allergies and intolerances to food. Intolerances differ from allergies (see “Not an allergy”, below), but they are often grouped together in studies. Last year, a paper examining 2.7 million health records found that 4.2 per cent of women have food allergies or intolerances, compared with 2.9 per cent of men. And this isn’t just a reflection of the apparent rise in gluten intolerance: the most common problem food for both men and women was shellfish, followed by certain fruits and vegetables. It is possible that women simply pay more attention to what they eat and their health, so are more likely to notice if they have a reaction, but biological factors seem to be involved too. For example, men have higher levels of a certain type of antibody thought to help block allergic reactions. And hormones almost certainly play a role because the gender difference in allergies switches at adolescence. Before puberty, boys are affected by allergies twice as much as girls.

Adult-onset hay fever often comes as a surprise to those newly affected – but it is true, you really can develop fresh allergies throughout your life. Just because you have never been allergic to pollen or peanuts, doesn’t mean you never will be. The flip side is that allergies can sometimes fade away, although this is rarer once you have entered adulthood. You are most likely to grow out of an allergy as a child. One study of more than 40,000 children in the US found that around 26 per cent outgrew their food allergies, usually by the age of 6. Egg, milk and soy allergies are those most often left behind. About 20 per cent of children lost their peanut allergies. When young children have eczema – a skin condition linked to allergies – this often improves in late childhood only for it to be replaced by asthma. The same children are then likely to get hay fever as teenagers, which tends to subside around their mid-20s. This procession of changing allergies is known as allergic march. Some symptoms from the old allergies tend to continue at

some level. “It often doesn’t go away, it improves,” says Arshad. The reason for this progression is still a mystery. “I wish I knew why it changes,” he says. “If I did, I could find a cure for allergies.” Drugs, hormones, other medical conditions and exposure to smoke and other air pollution may all play a role in changing allergies, says Neil Kao, of the Allergic Disease and Asthma Center, in South Carolina. After the menopause, women no longer experience allergies at a higher rate than men, he says. But if you think you have recently beaten an allergy, the chances are you have just been exposed to less of the allergen responsible. “Geographically moving is the single most common reason why people think they’ve outgrown their allergies,” says Kao. What of the oft-cited idea that allergies change every seven years? It is really a lot less predictable than that. “Every person’s immune tolerance levels fluctuate throughout his or her life, spontaneously and naturally. This is dictated by their genes,” says Kao.

NOT AN ALLERGY

Allergies are caused by the immune system unnecessarily responding to harmless molecules (see main story). But not all rashes, swellings or breathing difficulties are a sign of one. Food intolerance Food intolerances can involve bloating, wind, diarrhoea, itching, skin rashes and abdominal pain. These symptoms come on more slowly than those of food allergies, usually a few hours after eating certain things. For instance, some people report such symptoms after eating gluten, despite not having coeliac disease, an autoimmune disorder triggered by this protein component of cereal grains.

Chemical sensitivity As many as a quarter of people in the US say they are sensitive to fragranced products such as deodorants and air fresheners. People with these chemical 32 | NewScientist | 11 August 2018

sensitivities most commonly experience asthma when exposed to certain chemicals, although others report migraines, skin complaints or shortness of breath.

Nocebo effect Contrary to what some believe, allergies are not psychosomatic. However, another psychological phenomenon can make people experience allergy-like symptoms. The nocebo effect is a negative twist on the placebo effect, resulting in some people experiencing nasty symptoms even if a substance has no adverse effect on their body. One study found that 97 per cent of people who think they have a penicillin allergy are actually fine

with the drug. Another study, in which researchers gave allergenic or placebo foods to children with reported food allergies, found that placebo foods elicited allergy symptoms, including rashes, hives, diarrhoea and vomiting, nearly 13 per cent of the time.

Rhinitis Rhinitis is inflammation of the inside of the nose, causing symptoms such as sneezing and a blocked or runny nose. This can be a response to allergens such as  pollen or dust mites, but it can also occur in the absence of allergies. Causes include humidity, extreme temperatures, viruses and  exposure to air pollution such as smoke.

FACT YOU CAN BE ALLERGIC TO SEMEN An estimated 20,000 to 40,000 women in the US have seminal plasma allergy: an allergy to proteins in seminal fluid. In some women, this can cause hives, wheezing, diarrhoea and “post-coital anaphylaxis”, although this can be prevented by using a condom.

DO ALLERGIES COME IN GROUPS? If you know someone who can’t eat shellfish and also complains about dust, they aren’t (necessarily) just being picky. Allergies can come in a gang, and some combinations are more common than others. This is because allergies are caused by IgE antibodies recognising harmless molecules as a threat, and allergens with a similar structure can trigger responses in the same person. This often occurs in two phases. Typically, someone who developed an allergy to a common allergen such as pollen as a child will begin reacting to similar chemical structures in food later in life. This is called cross-reactivity and can lead to oral allergy syndrome: the rapid onset of local symptoms such as itching, tingling and swelling after eating certain foods. As many as 19 per cent of people may have it. “It’s a fairly common type of allergy that isn’t dangerous, but it can be quite annoying,” says Arshad. Tree pollen can cause allergies to a range of fruits, nuts and vegetables, such as apples, almonds and carrots. Ragweed allergies are associated with problems with melons, bananas, tomatoes and cucumbers, while mugwort pollen can trigger allergies to herbs and spices such as coriander, parsley, cumin and fennel seed. Many other groupings occur, including latex-related allergies to bananas, apples, potatoes and tomatoes.

CAN I PREVENT MY CHILD FROM DEVELOPING ALLERGIES? It was gospel medical advice for years. Women were urged to avoid commonly allergenic foods such as peanuts during pregnancy and breastfeeding, and were told that their children shouldn’t eat these foods during their first few years of life. The advice was designed to prevent kids from getting allergies. But in the past few years, we have discovered that, in most cases, this was wrong. Whether women eat allergenic foods during pregnancy turns out to make no difference, and they are no longer advised to avoid them. But certain things do seem to have an effect. A study of nearly 6000 infants last year found that being exclusively breastfed during the first four months of life seems to be linked to a reduced chance of developing hay fever in low-risk children. But breastfeeding isn’t the whole story.

Evidence is growing that, instead of avoiding allergenic foods, it may be important for high-risk children – those with moderate or severe eczema, or those whose parents or siblings have allergies – to encounter them early on. Those that are introduced to peanuts between the ages of 4 months and 11 months are 81 per cent less likely to develop a peanut allergy by the time they are 5. Similarly, children who begin eating eggs at the age of 4 to 6 months are less likely to develop egg allergies. Some guidelines in the US and Australia now recommend slowly and carefully introducing infants to potentially allergenic ingredients from the age of 4 to 6 months, although the World Health Organization still recommends giving babies nothing but breast milk until they are 6 months old.

The key appears to be exposing a baby’s immune system to potential allergens before they have a chance to develop allergies – a narrow window of opportunity. But how this works is still unclear and in many cases the evidence is contradictory. Eating peanuts early in life may be beneficial, but growing up in a home where a lot of peanuts are eaten seems to make peanut allergies more likely. The idea that a lack of “good” microbes in the gut may be to blame for rising allergies has prompted interest in using prebiotics to change the gut flora of a mother or her infant in order to protect against allergies. However, there is no good evidence yet that these work. ■ Penny Sarchet is deputy news editor at New Scientist 11 August 2018 | NewScientist | 33

INTERVIEW

Blue planet? It’s a dark, deep-ocean world Jon Copley dived deep for Blue Planet II. He tells Sam Wong about life in this extreme environment, the perils of plastic and, inevitably, the one that got away

34 | NewScientist | 11 August 2018

When was your first dive in a submersible?

It was an expedition with the US Navy’s deep submergence unit in the north-east Pacific 23 years ago. As it was a military unit, they inevitably liked to freak out scientists. When we reached the bottom, the pilot stood up and undid the hatch. But of course, the water pressure was holding it in place. It was an astonishing experience because the landscape is so different down there. I didn’t want to leave.

that atmosphere will turn toxic fast, which is why we carry backup breathing gear and eye protection. Why send humans down into the depths rather than just using remotely operated subs?

The remotely operated vehicles (ROVs) are superb now. Several ships are able to livestream high-definition video from one. I can sit at home in the middle of the night with my laptop, watching live images from the bottom of the Pacific Ocean and interacting with the team on the ship. That’s amazing. Yet there is something special about immersing yourself in the environment you are trying to understand. It might sound anachronistic, but NASA hasn’t given up on that ambition either.

What is it like to be in a tiny submersible for hours?

It’s cramped and cold. If you are looking for hydrothermal vents on the ocean floor, they are typically 2000 to 5000 metres deep, so it is an 8 to 12-hour dive. If you need to wee, you do it in a bottle. I’ve been on several trips where submersible pilots have had issues with kidney stones. I think this is because they avoid drinking. What did you see when making Blue Planet II that didn’t end up in the final show?

DAVID DOUBILET/NATIONAL GEOGRAPHIC CREATIVE

My favourite was the Antarctic sun starfish (pictured, right), which we nicknamed the death star. Unlike starfish on UK shores that have five arms, this has got about 50. What’s unusual is how it feeds. Rather than smothering its prey, it waves its arms up into the water to catch krill. The upper surface of the arms is covered in tiny pincers that snap shut when something brushes past. It was a challenge to film because the krill followed our submersible’s lights. If we stopped the sub, the krill swarmed around us. By the time we were ready to film the death star, its arms were already full of krill because we had inadvertently brought it this amazing dinner. Blue Planet II showed a moment when your sub started leaking. Everyone seemed surprisingly calm about it.

The metal-hulled subs have portholes with a seal around them. Many of them require high pressure to work properly, so they leak a bit on the way down. What scares me most in a sub is fire. You are in a tiny, enclosed atmosphere. It could just be smoke from something electrical overheating, but

upside down. We call it the blue planet yet actually the blue bit is only the surface layer. By area, it is a dark, deep-ocean planet. And the deep ocean is certainly not pristine: our everyday lives have been affecting it for a long time. When our great-great-grandparents travelled on steamships, the remains of the burnt coal from the engines were shovelled over the side. On well-travelled routes, that has shifted the seabed from a soft mud to cobbles, which in turn has changed the marine life in those areas. Back then, people had no notion this was happening. Now everyone is worried about plastics. What effect are they having in the deep ocean?

ROBERTO RINALDI/NATURE PL.COM; LEFT: TED GIFFORDS

T

HE BBC documentary series Blue Planet II brought the startling and diverse creatures of the deep sea to our screens more intimately than ever before. It featured the first ever dive to 1000 metres in the Antarctic, and ended with a warning about our impact on the oceans – particularly from plastic pollution. Marine biologist Jon Copley at the University of Southampton, UK, was a scientific adviser on the series and was on board the Antarctic sub for filming.

“It’s special to be immersed in the environment you are trying to understand” What else did you learn on the Antarctic expedition?

I became aware of the importance of “drop stones”. When the front of a glacier breaks off and forms an iceberg, it often has rocks stuck in its underside, which vary from the size of a fist to as big as a house. Eventually those rocks drop off. There was an exciting moment when our camera sub was filming something on the seabed and a fist-sized piece of rock dropped through the frame. If something bigger had hit the ROV, that could have been an issue! Most of the Antarctic seabed is rich, soft mud because it is mostly krill poo. Then a drop stone arrives and it is a rocky island in that landscape. A lot of marine life requires a hard surface to live on. In the Antarctic, that is mainly supplied by drop stones. Blue Planet II brought the deep sea to people’s attention a bit more. Do you think people’s attitudes to the oceans have changed recently?

To a lot of people, the deep sea embodies a pristine wilderness. There’s also this sense that it is alien. That’s what first captivated me. But now I think we look at the planet a little bit

We simply don’t know enough. Imagine life as a sea cucumber deep in the ocean, on a fine-mud abyssal plain. These animals plough their way through the mud’s surface, swallowing it, extracting whatever nutrients they can from the organic material that has fallen from above. Today, a proportion of that material is microplastics, which have no nutritional content. Even if this plastic weren’t toxic, ingesting it means the sea cucumbers have less energy for reproduction. What does that mean for their population in the long term? The knock-on effects are uncertain, and that’s just one impact of many we have started to appreciate. Why is it so important to explore the deep ocean?

To enable us to make informed choices. One choice we face relates to deep-sea mining. Some mineral resources are in increasingly short supply on land. For example, wind turbines require excellent magnets, which need neodymium. Manganese nodules on the abyssal plains of the eastern Pacific are a particularly rich source. Then there’s cobalt, which we need for electric-car batteries. Proponents of deep-sea mining argue that the direct impacts on human populations from this kind of mining are fewer, so in many ways this is a less deleterious form of mining. My view is that the deep oceans should be off limits until we understand more about them. We tend to rush in to exploit resources, realise we are having a bad impact, then bring in regulation. Here we have an opportunity to do it the other way around. What’s your outlook on the mining situation?

I’d call myself an optimistic futurist. If we are smart enough to get down there in the deep ocean to explore it, then we are smart enough to come up with alternatives to taking those resources. ■ Sam Wong is a reporter at New Scientist. Jon Copley will be speaking at New Scientist Live 20-23 September g More information newscientistlive.com/mag 11 August 2018 | NewScientist | 35

SUPERTOTTO

36 | NewScientist | 11 August 2018

Can’t hack it We can end cyberattacks if we radically redesign the computer chip, says Sally Adee

E

VEN if you’re not a hacker or a coder, chances are you will have heard names like Stuxnet, NotPetya or WannaCry. After all, these malicious programs have made big waves in the past few years. First it was Iran’s nuclear centrifuges that were the target, then Ukraine’s banks, then last year, hospitals in the UK. These cyberattacks keep coming. The standard response is to release software patches, the updates that pop up on our computers and smartphones. They are designed to seal up the holes that hackers exploit to smuggle their malicious code through. The trouble is, there are more than 100,000 holes out there – and that’s just the ones we know about. Plenty more are surely waiting to be found. “To successfully defend, you must find all weaknesses and plug them,” says Linton Salmon, who runs a computer security programme at the US Department of Defense. “To successfully attack, you only need to find one.” It’s a losing battle, and one we can no longer afford to fight. As we build the internet of things, putting simple processors into garage doors, fridges, light bulbs and windscreen wipers, that truth is only going to become plainer. If we are going to put computers in everything, it is time we souped up their defences. That is what Salmon and a few others have been quietly working on. We can protect ourselves from cyberattacks, they say, not with ever more patches, but with changes to computers’ underlying electronics. It means overhauling the way we build microprocessors, but the world’s biggest chip-makers are already getting in on the action. With a layer of protection at the heart of every chip, the hope is that we will stem the tide of cyberattacks. Most of us use at least two computers a day,

whether they be laptops, tablets, smartphones or smartwatches, and we are used to software like web browsers and spreadsheets doing our bidding. When you strike a key or click an icon, that instruction must ultimately be carried out by the computer’s hardware, specifically the processor, which is usually a single microchip. The building blocks of the processor are transistors – minuscule electronic switches – organised into functional components like memory and logic units. But software can’t communicate directly with transistors. Software is based on words and symbols, whereas transistors understand only two commands: switch on or switch off. To help the software and hardware communicate, there are go-betweens, such as programs called compilers that translate software instructions into machine code, a binary language of 1s and 0s, or ons and offs.

Big, dumb retriever How that translation works is determined by the chip’s architecture. This is the set of rules, embodied in the physical design of the processor, that governs how the software gets access to the hardware. It determines how much memory a program has access to, for example. “Think of it like a contract that tells the software people what to expect from the hardware,” says Richard Grisenthwaite of Arm, the firm that makes processors for most smartphones. The rules vary slightly with the processor, but all architectures are similar, particularly in one respect. “A chip is fundamentally gullible,” says Salmon. “Give it any instruction you like, and it says: ‘Okay, let me do that as fast as I can! Does it make any sense? I don’t care, you > 11 August 2018 | NewScientist | 37

STMICROELECTRONICS/COBHAM GAISLER

asked me to do it. You’re the boss!’ It’s like a big, dumb golden retriever.” There’s a good reason for this. In the 1970s, chips had only about 5000 transistors. To make processors as fast as possible, none could be wasted. Architectures were designed so that whenever software made a demand the chip would comply, no questions asked. Some 50 years later, the chips in your laptop and smartphone have about 5 billion transistors. But the golden retriever architecture has remained, largely because changing it significantly would make it incompatible with existing software. The unpleasant consequence is that when a hacker finds a sneaky way into a processor, it is only too happy to oblige any requests. That means it is possible to harvest sensitive data like usernames and passwords or get the processor to do nefarious deeds. The idea of making chips less gullible is not new. More than a decade ago, computer scientist Ruby Lee at Princeton University published designs for processors that would wipe parts of their memory automatically after a period of time. Back then, the big chip manufacturers weren’t interested, but that’s starting to change for a few reasons. For one thing, 5 billion is a lot of transistors. Processors are now so fast that we can afford the drop in speed when we devote a few to security checks. For another, we are increasingly spooked by hacks, and security is becoming a selling point.

Processors can contain 5 billion transistors but few are devoted to security

It’s not just Lee who has long seen the need for better security. In 2010, Howie Shrobe, a computer scientist at the Massachusetts Institute of Technology (MIT), went to the US government’s Defense Advanced Research Projects Agency, where he launched a programme known as CRASH. It posed a simple question: given everything we know about security today, how would we design computing infrastructure – hardware, software, servers, networks, the lot – if we started from scratch?

DEEP HACKS Some hacks depend on

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carry out its instructions.

speed, chips have long been

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updating computer code.

attack of 2017 locked up

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computers belonging to the

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“speculative executions”.

weaknesses in a machine’s

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hardware.

of hardware vulnerability

and Meltdown use this

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vulnerability to trick chips

to do with slices of a chip’s

that work in similar ways. In January 2018, two related bugs called Spectre

memory called buffers.

and Meltdown came to

since about 1995. Nearly

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every computer with an

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data. The trouble is, some

attacks would be tough

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carry out operations, to

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might check there’s enough

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processor. Once their code

memory available, for

out there.

have a flaw: if someone

38 | NewScientist | 11 August 2018

into doing what they ask. The bugs have existed

to detect. But the most disturbing fact about Spectre

The biggest problem the project identified was how interconnected computers are, giving hackers easy access to a lot of information. But that horse has long since bolted, so CRASH homed in on one way forward: redesigning the hardware. Salmon picked up where CRASH left off. He trawled the world’s most authoritative list of known computer vulnerabilities, kept by the Mitre Corporation, a non-profit organisation based in Massachusetts, and identified the most common hardware ones. There turned out to be seven main classes of hardware vulnerability, which together account for almost half of known hacks (see “Deep hacks”, below left). In 2017, Salmon launched a programme called System Security Integrated Through Hardware and Firmware (SSITH). It is giving nine competing research teams a share of $60 million to develop processors impregnable to all those seven classes of attack by March 2020. No one has tried anything this ambitious before. The gold standard of hardware defence is formal verification, a way of using fiendishly complicated maths to prove that the hardware does only what it should do. It requires rigorous checks to be made, which takes time. So far, it has only been used in custom-made chips for applications where human life is at stake, for example in flight control systems. That’s changing.“I looked into formal methods a few years ago and was pretty disappointed,” says Ben Laurie, head of security at the Google-owned artificial intelligence firm DeepMind. “But then I looked into it again more recently and was surprised by the amount of progress.” Salmon is similarly confident. He says improvements to algorithms should make formal verification of hardware practicable by 2020. Adam Chlipala at MIT is working on a processor design that uses formal verification as part of SSITH. “We’re building a compiler that automatically implements that idea,” he says. At the moment, however, his method only works for parts of chips, and it is uncertain how quickly it can be scaled up. A good backstop option might not be too distant, however, thanks to another line of research for SSITH: instead of radically redesigning processors, you can give them a partner to help them out. This idea is being taken forward by Draper, an engineering non-profit company headquartered in Cambridge, Massachusetts. Inside the main processor, every kind of data is

secure chips: nuclear plants for example. The people who run them “are even more paranoid than I am”, says Salmon. But those chips are expensive and slow, optimised for one job. You couldn’t use them in a smartphone or a laptop. Switching the processors in those everyday computers for something more secure would mean a huge upheaval. “It’s really not that simple to replace the systems that are out there,” says Katie Moussouris, an information security researcher who started Microsoft’s bug bounty programme, which pays hackers to report software vulnerabilities. So will it ever happen?

KOREA HYDRO AND NUCLEAR POWER CO. VIA GETTY

Armageddon chips

Some nuclear power plants already use “unhackable” chips

given a tag that specifies what security policies it must adhere to. Those policies are held on an adjacent coprocessor, which vets every action the main processor takes. If anything breaks the rules, the flinty-eyed coprocessor stops it. If it tries to find another way to execute, the coprocessor shuts down the program. Draper calls this an inherently secure processor. This set-up allows chip manufacturers the best of both worlds. Should someone identify a new hardware vulnerability, the policies in the co-processor can be updated without messing around with the main chip. “A new policy can be deployed almost immediately,” says Draper scientist Curtis Walker. It is as fast as a software update, and as strong as changing the hardware. Still, even if this prevents people from stealing passwords, continual attacks could force programs to shut down. That’s far from ideal – especially if the program is controlling something crucial, like an electricity grid or a nuclear power plant. Robert Watson, who studies secure computer architectures at the University of Cambridge, is working on a third way with colleagues at

Cambridge and at SRI International, a research institute in California. His architecture, called CHERI, traps malicious software, partitioning it off so it can do little damage. Think of what happens when everyday software like Microsoft Word freezes on your computer. You can force it to quit with a few clicks, and this won’t affect other applications. CHERI works in a similar way, at the hardware level.

“Hackers can get into chips – but then they’re trapped with nowhere to go” Let’s say a hacker emails you a corrupted image that, if clicked on, will trick your email software into sending malicious code to the processor. A processor using the CHERI architecture will construct a perimeter wall that isolates the compromised part of the processor. This wall is reconfigurable, so it can trap the enemy code in one mailbox, one email or even just the corrupted image itself. Attackers can get in, but then find themselves with nowhere to go. Some infrastructure already uses incredibly

There are reasons to be optimistic. Sarah Leeper, an engineer at Draper, works with a spin-off company called Dover Microsystems that is already marketing a commercial version of the inherently secure processor. Leeper says the firm is in touch with electricity grid operators who want to use it. The major microchip manufacturers have also begun to take less radical steps towards making hardware that helps constrain the software that runs on it. “We are already working on our own hardware security projects,” says Ronak Singhal, an engineer and senior fellow at Intel. Even the cheapest chips, those in devices that might be connected to the internet of things, could be switched. Arm’s primary interest beyond phones is in such devices, and Grisenthwaite says the firm has long been watching Watson’s CHERI architecture. “We are really interested in what he’s doing.” But hardware security is unlikely to end cyberattacks completely. “The ground is littered with the bodies of all the people who have ‘solved’ cybersecurity,” says Salmon. That’s partly because there will always be old systems in our computing infrastructure, not to mention attacks that rely on human gullibility: phishing, for example, or someone putting a sticky note bearing their password on their monitor. Sooner or later, something very important will be attacked, perhaps a power grid, bank or hospital, with major consequences. That’s why it is good to think about a hardware overhaul, says Lee. “We need a chip that we can use the day after the catastrophe,” she says. “If the change doesn’t happen before that day, it will happen after – and it will happen fast.” ■ Sally Adee is a freelance science writer based in London 11 August 2018 | NewScientist | 39

CLASSIC EXPERIMENT

Adventurer in time An extraordinary experiment on himself showed Michel Siffre that the body does have its own clock. Laura Spinney went to meet him

I

40 | NewScientist | 11 August 2018

Michel Siffre lived underground three times: first in France in 1962, then Texas in 1972 (right) and finally back in France in 2000 (left)

PHILIPPE DESMAZES/GETTY

N JULY 1962, Michel Siffre took off his watch and descended into the abyss of Scarasson in the French Alps. There, in a cave 130 metres below the surface, he set up camp next to a glacier. With a torch as his only light source, and deprived of all reminders of the passage of time, he lived underground, alone, for 63 days. When he emerged, wearing goggles to protect his eyes from the sun, the world’s press was waiting. Siffre was a geologist, but what he had originally planned as an expedition to study the glacier had become famous as something completely different: the first study of the human response to living with no information about time. Siffre was the first to show that our body might have its own clock. Since then, chronobiology has become a hugely important field of research. Now nearly 80, Siffre lives alone in a small apartment in Nice. It is so crammed with souvenirs, including giant fossil ammonites, that it resembles a cave itself. A ball of energy despite his age, he apologises for the disorder, although everything here, from the framed photos of his exploits to climbing equipment hung on the wall, demonstrates how this energy has been a defining feature of his life. As he shows me a tube of the electrode paste used on Apollo missions, he describes how the space race was his inspiration. Yuri Gagarin had just become the first man in space and the US and USSR wanted to know what effect long missions would have on astronauts. Without seeing day and night, it was assumed, a human would continue to function according to a 24-hour cycle, but that assumption had never been tested. Siffre decided to test it himself, although for the 23-year-old it was as much an adventure in timelessness as a scientific trial. “I was a geologist, not a biologist. I raised

the funds myself, picked the two months arbitrarily and invented the experimental protocol,” he says. In the cave, Siffre’s only connection to the world was a phone line to a camp on the surface, and someone was always there to answer it. He called on waking and before going to sleep, passing on information such as his pulse rate and temperature. His collaborators were instructed not to give him the slightest temporal clue.

Human dynamo His camp was on a small area of flat rock at the foot of the glacier. There was barely space to walk around. He passed the time thinking and reading the memoirs of Charles de Gaulle. Was he lonely? “Not really,

though I missed my girlfriend,” he says. “But I was 100 per cent motivated. I was a human dynamo.” The experience was physically harrowing, nevertheless. It was 3°C in the cave, and condensation pooled on the floor of his tent so his feet were permanently wet and cold. Worse, lumps of ice and rock would periodically fall from the glacier and crash nearby, terrifying him. After one particularly hair-raising rock fall, he stayed on the phone for more than 10 hours, though it didn’t seem that long to him. His perception of time had changed: “Two seconds passed, I perceived one.” He kept a diary. The experiment was due to finish on 14 September, but on what he estimated to be 20 August he learned his time was up. He was 25 days out.

by lightning that travelled down the cable connected to the electrodes on his body, giving him a violent jolt. Psychologically, however, Midnight cave took a terrible toll. Three months in, he cracked. Overwhelmed by a feeling that he was wasting his time and betraying his vocation, he ripped the sensors off his body. But he didn’t ask to leave the cave, and he carried on doing the cognitive tests. After 10 days, a sense of duty made him connect himself back up again. “But from then on the cave became my prison,” he says. If it hadn’t been for an iron will – his philosophy of marche ou crève (which translates as walk or die) – and a small female rat he befriended, he is convinced he wouldn’t have completed the experiment. In Midnight cave, Siffre’s sleep-wake cycle

PAUL SLADE/PARIS MATCH/GETTY

“His perception of time had changed: ‘Two seconds passed, I perceived one’ ”

He emerged exhausted, but with his spirit intact, although there were some temporary after-effects. He would play the same record over and over again, forgetting that he had just heard it. Not much is known about the effects of timelessness on memory, but Siffre has his own explanation: “You’re a point of light in a permanent darkness,” he says. “The brain grasps no time because there is no time. Unless you write down what has happened, you forget it immediately.” It wasn’t only his perception of time that had changed. In the cave, his sleep-wake cycle had increased to 24 hours and 30 minutes. He had gone to sleep and woken a little later each day, until he had become nocturnal. It showed, Siffre said, that the body had its own clock. But scientists didn’t accept that idea easily. “They thought I was mad,” he says.

Over the next decade, he oversaw a series of experiments in which other volunteers went without time cues for up to four months. These demonstrated that the body’s clock could be extended into a 48-hour cycle, something Siffre hadn’t achieved in Scarasson. That was one reason why, in 1972, he decided to test himself again. He had another motive: “People were whispering that I was happy to send others down, but not myself; that after Scarasson, I was afraid.” This time he spent six months underground in Midnight cave in Texas – the longest period of timelessness anyone had attempted to date. Technology had moved on since 1962. Electrodes stuck to his scalp and body monitored his physiological activity, and he performed daily cognitive tests. There were no physical threats, though he was once struck

stretched more slowly than it had in Scarasson, but it stretched further, and he twice achieved a 48-hour cycle. But he also got depression, which lasted for many months after leaving the cave. It wasn’t helped by his financial situation: he had been obliged to foot the bill when funding ran out. “I was broke,” he says. He went off to explore cave formations in Guatemala, and it was only in 2000, after learning that the 77-year-old astronaut John Glenn had returned to space, that he decided to undertake one last adventure in chronobiology. Now 60, his aim was to explore the effects of ageing on the body clock. After two months in a stalactite-encrusted cave near Montpellier, France, he found that his sleep-wake cycle evolved as it had in his 23-year-old self. Siffre’s investigations launched a line of study that culminated in a Nobel prize in 2017 for the three researchers who identified the genes governing what we now know to be multiple body clocks. It contributed to the invention of light therapy for mood disorders and drugs for jet lag. Revisiting those experiments, however, it is difficult not to be struck by how biomedical ethics has moved on. None of the many organisations that supported Siffre’s research questioned the ethics of it, or offered him psychological support. But then, Siffre expected nothing more. Surrounded by memories of a life richly lived, he says, “Je ne regrette rien.” ■ Laura Spinney is a writer based in Paris 11 August 2018 | NewScientist | 41

CULTURE

Unleash your virtual hero

Niall Firth: I tried a prototype of Oculus in 2013, when it was still big and clunky and didn’t have controllers. I was amazed then – but it’s so much better now. Hannah Joshua: Unlike both of you, I stayed as the same character the whole time: Black Widow. The basic controls were simple enough. But it is easy to lose track of which button does what and you risk hitting the wrong one in the heat of the moment. But this can work to your advantage. I made myself invisible by accident through button-mashing and sneaked up on some enemies. Sam Wong: As Captain America, the key skill I had to learn was grabbing the shield from behind my back, launching it like a discus, then catching it as it flew back to me. It was difficult to aim at first but, after a while, I honed my throwing action to make sure it went off in roughly the right direction. I’m sure I looked like a prat though – I don’t know how long you have to spend in VR before you forget that your real body is in a room with a contraption strapped to your face,

Out of this world: Sam Wong puts the virtual in reality 42 | NewScientist | 11 August 2018

waving your arms like a loon. NF: I felt deeply immersed and I was quickly unaware of what the real me was doing on the outside. My sense of balance was thrown and it made me feel a little dizzy – especially when I glanced down and whoa! I could see Captain America’s massive thighs pounding the streets beneath me. HJ: I was in a different team and managed to shake hands with one of my teammates – I think it was Storm – before we started our

GILEAD AMIT

WANT to be Black Panther from Wakanda? Or maybe Captain America, Black Widow or Spider-Man? Now virtual reality is finally coming to domestic gaming PCs, you have the chance. Oculus Rift has teamed up with Marvel to produce Marvel Powers United VR. But how does total immersion in a game like this feel? Three New Scientist staff members popped on headsets, slugged it out, and chewed it over afterwards.

OCULUS STUDIOS

Niall Firth, Hannah Joshua and Sam Wong try out Marvel’s new Oculus Rift game

Marvel Powers United VR lets you step inside the country of Wakanda

get on your knees and grope about on the floor for your weapon than to make a mistake in an ordinary video game. Playing in VR highlighted the skill involved in wielding a weapon, and the stakes felt higher when you could literally turn your head and be face-to-face with an enemy. NF: The game seemed pretty linear. You’d follow blue arrows to move to the next part of the street and await your foes. Yet the deep immersion – and the graphics that eclipsed anything I’d seen in VR before – made it engaging enough. I just wonder if, beyond that first level, the novelty would begin to wear off given the path is so explicitly signposted. To be honest, I found myself spending a bit too much time gazing around at my surroundings, or experimenting

match, which made me feel surprisingly connected to the random strangers I was playing with. It was weirdly intimate. SW: I’m not sure how long we “It made me dizzy. played for – I lost track of time Especially when I looked until I heard a voice near me down and saw Captain suggesting it was time to return America’s massive thighs” to reality. It was a bit of a workout to play so when I took off the with my Spider-Man leaps, headset I was sweaty and dizzy, rather than helping my fellow but I would have happily stayed superheroes. SW: I had children’s voices in in the Marvel world for longer. my ear telling me what to do, Did you want to keep going? NF: No! I was first to remove my which was a bit unsettling! headset when I suddenly realised I was Spider-Man for this part too, I felt very queasy, like being car so I did my best to shoot strands sick. As I took it off I could hear of web at the enemies, but I was one of my team mates inside struggling a bit with the controls the game calling for help. and I was a bit worried I was letting Sorry, I thought, I’m through. the side down. Still, we succeeded HJ: When it was time to leave, in fighting off the attack. I almost found myself glancing at HJ: You succeeded? I think we did the door and flexing my thumb to too. Sometimes the info display was a bit overwhelming to read, jump over there, like I did in the but if this catches on, a lot of game. I’d be a terrible superhero gamers are going to get a lot more – I kept dropping my energyexercise. I was pleased I didn’t shooting batons! Somehow it is come last in my team. ■ more embarrassing to physically

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

DON’T MISS

How Ötzi came to life

Read Michael Lannoo, whose own adventures have carried him to both polar and tropical regions, turns historian to celebrate the muckier side of biology in This

Catherine Brahic on a delicate film portrait of an ancient iceman

LIKE many modern lives, the film Iceman starts with sex, a birth and a religious ritual. When the mother dies in labour, her child is adopted. Surrounded by rugged mountain peaks, the newborn is wrapped in furs and lifted high above the clan’s heads as they chant in an ancient tongue. Later, there is an attack on their settlement. Men, women and children are killed, their wooden huts set alight. Something is stolen. Two people escape: the baby – miraculously spared – and a clan member off on a solitary hunt. He sees the flames and races down but is too late. Thus begins the epic journey of Ötzi in Iceman, a film by German writer-director Felix Randau. He took research on the real iceman Ötzi – renamed Kelab for the film – as his starting point, saying that it “left me enough freedom for the

MARTIN RATTINI FOR PORT-AU-PRINCE FILMS

In Iceman, Ötzi becomes lone hunter Kelab, out for vengeance

fictional aspect that was meant to merge logically and organically with the historical facts”. In their imagined version, Kelab sets off over the Alps with the newborn in a fur sling, fuelled by the desire for revenge. Ötzi’s body was found in 1991 by hikers 3000 metres above sea level in the Ötzal-Alps. He turned out to have died 5300 years ago, and is among the best preserved human remains from that time. Along with many of his clothes, shoes, a hand axe, a bow and unfinished arrows, he has yielded unprecedented insights into life during the Copper Age. We know that his home was 20 kilometres south of where he was found, and at a much lower altitude. And his end was violent: scans showed a flint arrowhead in his left shoulder. He was clearly in trouble, with dulled tools and no way to sharpen them. Some suggest he was fleeing a disaster. This possibility gives the narrative its direction. It is a pretty standard revenge story: violent attack, robbery, a chase

through inhospitable landscapes. Both sides incur losses; both sides are flawed. But we mostly root for the lone hunter even though we can see he is also prepared, even yearns, to kill. The friend I watched it with was unimpressed. The Revenant, he said, had rendered the same plot to greater effect. It’s true. But for those who are interested in human origins, I think there is more depth and delicacy to this film. As Kelab leaves his village, we see him pack. He crouches beside a fire, pulls out a smouldering ember, wraps it carefully in something and pops it into a container. Clearly, this is a nod to the birchbark containers found with Ötzi that are believed to have been used to carry embers. Then there are more intangible details. Copper Age people most likely had some mystical beliefs. In the film, these (and a reveal) involve a mysterious wooden box called Tineka – a shrine of sorts – stolen by the attackers. The dialogue is delivered in a fictional language, developed by linguist Chasper Pult. His words and phrases could pass for ancestral Rhaetian, once spoken in the Alps. But there are few words, really. A loneliness and deep sorrow accompany our solitary hunter. He happens upon a few other people on the way but they don’t share his language. It is these complex relationships I was most struck by. They give a better sense of our ancestors’ mental landscape than any mummified remains ever could. Don’t watch Iceman if you want Hollywood-style narrative thrills: it is a portrait, not a drama. After all, we know how the story ends. ■

Visit TechHub London is the venue for a discussion titled Power in the Digital Age on 14 August. Kicking around today’s biggest issues will be Areeq Chowdhury of digital politics think tank WebRoots Democracy and Carl Miller, author of the forthcoming book The Death of the Gods: The new global power grab.

Listen Annie Minoff, co-host of Science Friday’s fantastic Undiscovered podcast, will join two authors to discuss great science writing at the American Writers Museum in Chicago on 16 August. The second series of Undiscovered will be released any day now.

Last chance The exhibition My Monster: The human animal hybrid at Melbourne’s RMIT Gallery has proved one of the more adventurous celebrations of Frankenstein’s bicentenary. Catch works like Julia deVille’s Peter, shown below, before the show closes on 18 August.

JULIA DEVILLE/SOPHIE GANNON GALLERY

Iceman, directed by Felix Randau, UK cinemas and on demand

Land Is Your Land: The story of field biology in America (University of Chicago Press).

11 August 2018 | NewScientist | 43

CULTURE

Amazing apians

USGS BEE INVENTORY AND MONITORING LAB

Bees are beautiful and diverse, even though they’re just hippy wasps, finds Matthew Cobb

Buzz: The nature and necessity of bees by Thor Hanson, Icon Books

THINK of a bee and you will probably imagine either a honey bee or a bumblebee. But in Buzz, Thor Hanson reminds us that the apian community is incredibly diverse, with most species solitary, without hives, queens and stings. Hanson, a US conservationist, expertly explores the history and ecology of bees around the world, concentrating on North American species. He regularly returns to his favourite, the alkali bee, a solitary insect with shimmering stripes that nests in salt-saturated ground in the western US. Almost all bees are vegetarian, their fate tightly linked to flowering plants. They feed on nectar and pollen (honey is produced only by social bees, which eat it when there are few flowers or it is too cold to fly). The bees’ ancestors, the wasps, however, are mostly carnivorous. 44 | NewScientist | 11 August 2018

Around 100 million years ago, one modern bee genomes suggests group began to eat pollen, feeding many species went with them, it to their larvae. This evolutionary shaping modern bee diversity. innovation led to the 20,000 Hanson is particularly species of bee we have today. Bees, interested in the role of bees in it turns out, are just hippy wasps. human society and evolution, The basic deal with bees and exploring our sweet tooth and plants is that the plant gives the the significance of honey in prebee some sugary nectar, and the industrial societies, including in bee gets covered in pollen, some Africa, where honey bees originate. of which it feeds to its young, and He also describes how US alfalfa some of which pollinates another “Some bees steal nectar flower. Despite this apparently hidden too deep for them fair arrangement, Hanson shows to reach by biting a hole that both sides repeatedly try to at the base of the flower” gain the upper hand. Some orchids produce no nectar but fool male bees into farmers encourage his beloved rummaging around on the pollen- alkali bees, which are efficient producing stamens by smelling of pollinators, by creating salty mud female bee pheromone. And some fields where the bees can burrow, bees will steal nectar hidden too laying an egg next to a ball of deep for them to reach by biting a pollen that will feed the larva. hole at the base of the flower and The pages of Buzz are full of bypassing the stamens. quotes from bee experts and One aspect of this link between farmers. This makes for easy plants and bees that Hanson reading, and the book can feel doesn’t explore is what happened like an extended magazine article. when an asteroid hit Earth I would have liked more science, 66 million years ago, shattering covering how social bees organise its ecology. Many flowering plants their hives, for example, and the went extinct, and a comparison of fundamental question of how

Centris decolorata and Diphaglossa gayi, bees from South America

and why workers in social species give up their ability to mate. But there are beautiful colour plates of 16 bees (two are shown above), as well as simple descriptions of the seven families of bees. These provide an excellent graphic complement to the text so we can all marvel at the tiny, wonderful pollinators. The final chapters deal with contemporary threats to bees, describing the complex reality of the “colony collapse disorder” that affected honey bee nests, and taking a balanced view of the factors that led to a decline in both wild bees and farmed honey bees. Hanson’s son, Noah, appears at various points, getting involved in experiments and observations. A perceptive quote from him closes the book, summing up the significance of these insects: “The world could do without us, but it couldn’t do without bees.” ■ Matthew Cobb is a zoologist at the University of Manchester, UK

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

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11 August 2018 | NewScientist | 49

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This could be you: A NASA Postdoctoral Fellow investigates short gamma-ray bursts that could be from the same cosmic collision that created the gravitational waves that were detected by LIGO, the first-ever observation of gravitational waves.

Become a Fellow. Contribute to history-making research.

npp.usra.edu

Fields of study include:

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Fermi GBM Observations of LIGO Gravitational Wave event published by V. Connaughton, USRA, E. Burns and A. Goldstein, NASA Postdoc, et al.

Image Credit: NASA/C. Henze

50 | NewScientist | 11 August 2018

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LETTERS EDITOR’S PICK

Neural correlates of consciousness and a theory of mind solution

From Guy Inchbald, Upton-uponSevern, Worcestershire, UK Catherine de Lange discusses the hunt to understand consciousness (30 June, p 30). It may not be particularly tangible. Consciousness is associated with the information patterns carried by nerve signals. It is what information feels like when it

52 | NewScientist | 11 August 2018

reaches a certain kind of complexity. In artificial intelligence research, neural networks try to mimic the way the brain works by making huge numbers of connections between nodes. Machine learning distributes its discoveries across this network in an impenetrable manner, analogous to the way a hologram distributes every part of an image across the whole recording. Neither can be understood by analysing what each node or pixel is doing. This suggests that the physical “seat” of any particular information in the brain may be widely diffuse. Two identical neural networks presented with the same learning material and procedure will develop different connection patterns. We also know that people can differ widely in the way their brains develop and learn to respond to stimuli: for example

people who are blind may process touch data within their optical cortex. So the physical seat of consciousness may be moveable, diverse and of no real value to cognitive science. Unless we are brain surgeons, we would do better to focus on the information.

From David Newton, Chelmondiston, Suffolk, UK De Lange’s summary of consciousness studies could have been subtitled: “how to be conscious about thinking”. Having a theory of mind –”I think that you think…” – is a well-understood concept applied to many social primates, including humans. Doesn’t it also apply to our sense of self? If we hypothesise our thoughts and feelings in the same way as we do others’, the “mystery” of consciousness disappears – it’s simply how we think we are thinking.

@newscientist

newscientist

Cataloguing climate change contributions From Robert Anker, Currumbin Valley, Queensland, Australia Roger Taylor suggests compiling a list of all the things that might be contributing to climate change (Letters, 25 June). There is already such a list, and it also shows how to reduce emissions already in the atmosphere, with rankings, costs and benefits, in great detail. Paul Hawken’s book Drawdown has a website at drawdown.org.

Autism, acceptance and altering attention From Ametrine Lavender, Heptonstall, West Yorkshire, UK Your interview with Anna Remington mostly does a good job of describing the strengths as well as the difficulties associated with autism, and helps counteract

“It’s sad how secret miscarriages are, or how much they are viewed as a taboo” Gachiru responds to the news that women have more miscarriages than live births over their lifetimes (4 August, p 8)

the negativity of much writing about autism and autistic people (14 July, p 32). But I am bewildered by the idea that it is the result of too much unoccupied attention. Most autistic people would tell you the opposite, and years of research backs up the idea that we have very focused, unidirectional attention capacity, so asking anything extra of us tends to show that we can’t divide our attention between stimuli. I am very absorbed, focused and “in the zone” when writing an academic essay, to the point that it is painful to emerge. Yet if someone parks their car outside with the radio on, I cannot process that stimulus and keep up concentration. That asks too much of me, not too little. Anna Remington writes: ■ We still don’t fully understand attention, but our research and

that of others suggests autistic people can process more information at any one time, rather than having unoccupied attention. This extra attentional capacity can result in useful skills, but, as your experience shows, may also lead to distraction. Many autistic people have told us that this concept of increased capacity – with its positive and negative consequences – fits with their sensory experiences.

Intelligence scores, correlation and cause From Chris Cox, Cambridge, UK Linda Geddes writes that around 50 per cent of the difference in intelligence between people is due to genetics (21 July, p 33). There is certainly a correlation, but correlation does not necessarily imply cause. Indeed, you took a different approach in an article on

sexism, arguing that the cultural amplification of small biological differences results in a huge gap between how men and women think of themselves (21 April, p 37). I argue that genetic differences in intelligence are amplified by the environment, through interactions such as praise, motivation and opportunity. This seems entirely consistent with the observations. In particular, it immediately explains why the correlation between genes and IQ becomes stronger with age, which is otherwise difficult to understand.

where individual welfare is largely determined by having a job, the displacement of human jobs is an important issue. But the increased spending that is supposed to follow might not be a cause for celebration. Will it have a large ecological footprint and be for the monetary benefit of a few? Or will it fit within the safe space for planetary ecology, and be for the benefit of entire communities, even if that means what some call “degrowth”? Jobs are not always a measure of collective progress and well-being. They can be a measure of destruction and misery.

It matters what kind of jobs robots aren’t taking

The last thing the world needs is aircon in Canada

From Veljko Armano Linta, Zagreb, Croatia You report a study finding that robots won’t be taking our jobs (21 July, p 5). In our societies,

From Tom Smith, Basel, Switzerland Discussing heat-related mortality, Michael Le Page says that more than a dozen deaths have been >

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LETTERS blamed on a heatwave in Canada (14 July, p 25). He concludes that without air-conditioners, large numbers of people will die in future heatwaves. Over 50 million people die in the world each year. It’s estimated that around a million of these deaths are related to temperature. But at high latitudes, far more people die from cold than from heat. Milder winters may actually reduce overall mortality rates here. Heatwaves kill increasing numbers, predominantly in the tropics. The last thing the world needs is for Canadians to install air-conditioners.

Did life get started between sheets of clay? From Chris Eve, Lynton, Devon, UK Penny Sarchet discusses whether life may have originated in an ocean vent, a hot spring or a geothermal field (16 June, p 30). What about clay that consists of stacked, charged sheets? The distance between these varies with the amount of water and dissolved ions present, and they TOM GAULD

can separate completely in brine. Consider clay that’s part of a soil intermittently wetted by rain and tides. Its charged sheets could act like membranes, allowing organic species to assemble, compressing and stabilising them, and then releasing them.

Our Christian duty to our neighbours in time From Fred White, Keyworth, Nottinghamshire, UK Katharine Hayhoe’s perspective is a welcome Christian insight on approaches to climate change (7 July, p 40). It may be a surprise to some, but Christianity’s prime directive is to love your neighbour as yourself. Looking at the current state of play, we have a big problem with this. In terms of the environment, it must be acknowledged that we also have “neighbours in time”, some of whom may, we hope, be our descendants. We are robbing these neighbours blind when we extract resources and fossil energy from the earth. Then we pass the resulting mess on to them, expecting them

to clean up for us or to live with the consequences. Truly, may God forgive us.

More stupidity of smart electricity meters From Sam Edge, Ringwood, Hampshire, UK Colin Foan suggests that smart electricity meters can reduce the problem of peak demand exceeding supply (Letters, 7 July). This would be more directly true if the meters could communicate with smart appliances – for example, to ask your fridge to turn itself down for a while. The “smart” meters currently being rolled out in the UK have no such capability. No protocol for such interactions has yet been agreed in the UK or EU. Not only are we wasting money installing the current generation of “smart” meters and throwing away the existing ones, we are going to have to do it all over again in five or 10 years once such a standard is agreed. It would make far more sense to stop the roll-out immediately and resume it only once that’s in place.

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People picking plastic pollution could get paid From Hillary Shaw, Newport, Shropshire, UK What to do about plastic (19 May, p 25)? On most roads in England I see miles of verge littered with thousands of pieces of plastic, much of which will end up in the rivers and sea. If governments are serious about plastic pollution, why not declare a month in which people bring bags of plastic waste to recycling centres and are paid, say, £1 per kilogram? This could redistribute income too.

Space is the place but Sutherland isn’t From Don Trower, Braintree, Essex, UK Does anyone else question the wisdom of the UK’s first spaceport being in the remote Sutherland area of Scotland (21 July, p 5)? Consider the distance that payloads, fuel and staff will have to be transported, and uncertainty over any future relationship with Scotland, given that it may not remain a member of the UK. Sutherland launches will be called off if more than an inch of snow falls or there is wind.

For the record Q The planet 55 Cancri e is nine times as massive as Earth (21 July, p 38). Q The crucifix ground beetle is extinct in many localities but not in the UK as a whole (28 July, p 28). Q Odds off: in the long run, a 50:50 chance of a £6 pay-out should return more than a guaranteed £2.70 per round (21 July, p 10).

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 | 11 August 2018

CROSSWORD Compiled by Richard Smyth

A thirteen-year-old girl wakes up in a future where human emotions are extinct and people rely on personal-assistant robots to navigate daily life. A novel of the robot age written by a leading researcher in robotics and artificial intelligence.

Crossword No21 Buy Now at mitpress.mit.edu/vestigialheart

ACROSS

1 4 10 11 12 13

14 15

Part of the female reproductive mechanism of a flower (6) Rumen, reticulum, omasum and abomasum, for instance (8) Grass fibre from the Mediterranean region (7) 1985 sci-fi novel by Carl Sagan (7) The only even prime number (3) Irene ___ (1897–1956), joint winner of the 1935 Nobel Prize for Chemistry (6-5) Three-part brain structure first proposed by Paul D. Maclean (6) Condition that may be congenital, chronic or idiopathic (7)

19 Human-like automaton (7) 20 In electronics, a valve composed of three electrodes (6) 23 Traits developed by evolution in response to environmental factors (11) 25 Extinct bird of New Zealand (3) 26 Oceanographical feature also called a shoal (4,3) 27 New World woodpecker (7) 28 Portable mechanical cutting tool first developed for use in surgery (8) 29 Theoretical means by which a memory is stored in the brain (6)

DOWN

1 2 3

5 6 7

8

In geology, another name for soapstone (8) Mechanical process by which an object collapses in on itself (9) Smithsonian zoologist (1860–1943) who described more than 1000 new species (4,4,7) Relating to the structure of Earth’s crust (8) Obsolete name for bipolar disorder (5,10) Electric ___, execution device conceived by US dentist Alfred P. Southwick (5) Joe ___ (1921–2016), “father of the 747” jumbo jet (6)

9 ___’s Law, principle relating to gas pressure (5) 16 Carolyn ___ (b.1929), US astronomer who discovered 377 minor planets (9) 17 Genus of bacteria that can cause serious illness in humans (8) 18 Six-pointed star shape (from the Greek) (8) 21 pc (6) 22 Heinz ___ (1928–2017), German-born scientist known for presenting The Great Egg Race on the BBC (5) 24 Suspension of breathing (US spelling) (5)

Answers to crossword No20 ACROSS: 1 RHEBOK, 5 STINGRAY, 9 INFRARED, 10 TREMOR, 11 PSILOCYBIN, 12 SITE, 13 INFERIOR, 16 ECOBOT, 17 PRIONS, 19 FRANKLIN, 21 CHIP, 22 MASS NUMBER, 25 AT REST, 26 ECLIPTIC, 27 FREEWARE, 28 STEREO. DOWN: 2 HANDS, 4 KARACHI, 5 SIDEBAR, 6 INTENSE, 7 GUESSWORK, 8 A FORTIORI, 14 NORTH STAR, 15 EXOSPHERE, 18 SUMATRA, 19 FISHEYE, 20 ANNULUS, 23 MAPLE, 24/3 EMILE BOREL.

11 August 2018 | NewScientist | 55

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FEEDBACK

A SHARK that was smuggled out of an aquarium in a baby stroller has been found alive after a two-day search. Staff at the San Antonio Aquarium in Texas spotted a man lifting the 40-centimetre-long horn shark out of an open tank on 28 July. He then wrapped it in a wet blanket and placed it in a bucket inside the stroller. After being confronted by the aquarium’s general manager, the man and two accomplices fled, but their vehicle was soon tracked down. The shark was returned to the aquarium in “very good condition”.

IT IS a question that has troubled thinkers throughout history: “What if the entire Earth was instantaneously replaced with an equal volume of closely packed, but uncompressed, blueberries?” Now we have an answer, thanks to Anders Sandberg at the University of Oxford, who has published a fruitful analysis on the preprint server arXiv. A person standing on the surface of Earth when it turns to blueberries would first feel a drastic reduction of gravity, reports Sandberg. The blueberries would compress rapidly, resulting in “basically the worst earthquake ever, and it keeps on going until everything has fallen 715 kilometres”. At the same time, the blueberries would heat up rapidly. “The end result is a world that has a steam atmosphere covering an ocean of jam

PAUL MCDEVITT

on top of warm blueberry granita.” According to Sandberg, the physics of blueberry Earth is actually “fairly normal” compared to some exotic exoplanets. Maybe a blueberry planet is out there – somewhere in our pancake-shaped galaxy.

MORE galactic weirdness: Jeff Dickens is still a little puzzled by our item on cosmological unit pedantry over parsecs (28 July). He writes: “I am surprised you made no mention of the recent Han Solo film, seemingly written to ensure that the apparently annoying use of parsec in the original movie acquired a rational explanation.” In a neat piece of retconning (the literary practice of rewriting the past to explain away plot holes), the “Kessel Run” is declared to be measured in units of distance, not time. “I strongly suspect there exists a Venn diagram of readers who are pedantic about cosmological units, those who are pedantic about Star Wars, and those, like me, who can be pedantic about both,” he says. “But what are the relative numbers? Is the overlap large or small?” Large or small, Jeff, our inbox suffers equally: the Venn diagram of Feedback readers and pedants is clearly a perfect circle.

Toby Bateson has weeded out another case of nominative determinism in the pages of New Scientist, where he learns that one David Potter works at the UK’s only legal cannabis farm 56 | NewScientist | 11 August 2018

SPEAKING of excursions, many of us are off on our travels at this time of year, and the animal kingdom is no exception. Yet the swift and the swallow have no way of checking on the desirability of their destination. If they could log into TripAdvisor, we imagine it might go something like this: Yalu Jiang estuary, China, from user A. Godwit “A large group of us had a two week layover en route to Alaska. Despite concerns about the political situation just over the border in North Korea, we felt very safe. Sadly the selection of shellfish in the breakfast buffet was very poor, and I left starving. Two stars.” Sefton Park, Liverpool, from user Goosie_G “We’re not really ones for going away at the holidays, but we decided to visit the pond here during our “staycation”, as it’s just a short flight from Prince’s Park. We were having a lovely day until someone told me to ‘go home’. I was born here pal! Just because we’re called Canada Geese doesn’t mean we’re not British.” Spitsbergen island, Norway, from user White_Bear “I decided to venture further south this summer, as all my usual haunts have gone into liquidation. Was utterly famished the whole time. Ran into some locals, very unfriendly. Not pleased to see me at all. One star.”

Serengeti National Park, Tanzania, from user StarChild2015 “This was my first time walking the Serengeti and I believe it’s a MUST for everyone. Yes it’s hot, dry and dusty, but it’s all about the atmosphere and the vibe and being around like-minded individuals. On the trail, you can be free, truly free, to be who you are. Especially if what you are is a wildebeest.” Roach Motel, under the fridge in the kitchen, from user GregorSamsa “I recently discovered this small boutique motel during one of my nightly walks. I must say it looks very inviting. I think it will be good, as it was so full I couldn’t get in. Nobody looked like they were about to leave any time soon.” Ria Formosa Nature Reserve, Portugal, from user Little_Bittern “This year we headed to the Algarve for sun, sea and sand.

What a blast! Loads of ex-pats there, no need to learn the lingo. Friendly locals, plenty of eating spots. Had a dance with another long-legged bird, and next thing I know, I’ve got six mouths to feed.” Next week, we review the Tinder profiles of parasites and hosts seeking compatibility online.

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

Last words past and present at newscientist.com/lastword

THE LAST WORD Flower underpower

A tad late

Why does a bee only visit one type of flower at a time? It seems such a waste of energy.

Q Bees usually visit flowers for food in the form of nectar and pollen. At face value, bees’ fidelity to one type of flower at a time, or flower constancy, seems unintuitive. After all, a huge variety of different flower species exists in nature, so why would bees bother seeking out a particular species when a different one much closer might be just as good? In addition, bees might be expected to visit multiple flower species to maintain a healthy balance of nutrients in their diet. However, flower constancy is thought to evolve because it actually improves the bees’ foraging efficiency. By learning to identify the scent and appearance of one flower especially well, it is easier for bees to locate that flower. There are some species of bee that visit many flowers, such as leaf-cutter bees. It is possible that such species have more of a struggle identifying and locating flowers, giving them a lower foraging rate overall. Nonetheless, bees that visit a range of flowers have an extended flight season compared with more specialist bees, as they can exploit flowers that emerge at different times of the year. Sam Buckton Cambridge, UK

I was cleaning my garden pond in Staffordshire, UK, at the end of October and came across a live tadpole. I had previously suspected that some tadpoles are late undergoing metamorphosis, but this one really missed the boat. Is this a recognised phenomenon, and what is the explanation?

much throughout the UK. It seems that the tadpole gains an advantage by deliberately delaying metamorphosis and overwintering, because it then emerges as a larger frog than usual. They may be able to do this because of warmer winters brought about by climate change. Terence Hollingworth Blagnac, France

Q One has to assume that this is a tadpole of a frog or a toad, although it could have been the larvae of a newt, which is not dissimilar to a tadpole, except that it has feathery external gills. That said, there are only two species of toad, the natterjack and the common, and three species of frog, the American bullfrog, the marsh frog and the common frog, recorded for Staffordshire. We can discount the toads, because both breed early in the year and a garden pond is unsuitable for a natterjack. For the frogs, the American Bullfrog has only been seen once in Staffordshire, which leaves us with the marsh and the common frog as the likely culprits. There are frogs that overwinter as tadpoles in ponds, and one of these is the marsh frog, but once again we have the wrong habitat. That makes the common frog the most likely candidate. This normally breeds early in the year and has usually metamorphosed before late August. However, overwintering is not an uncommon phenomenon and has been documented pretty

Q Frogs and toads lay eggs, called spawn, in early spring. These hatch after a couple of weeks and the tadpoles grow and metamorphose to form miniature versions of the adult form. Transformations also occur inside the animal as its internal organs alter to cope with “I put iodine into the tadpoles’ rainwater crock. a changing diet. Days later the yard was Sometimes metamorphosis teeming with small frogs” can be delayed if environmental conditions are not conducive for maturation. Overcrowding, with put a few drops of iodine in the resultant food shortages, and low crock. Days later, the yard was water temperature may slow teeming with small frogs. growth. Such tadpoles have to It might be interesting to overwinter in their pond and, discover the iodine content if they survive the cold, will of Staffordshire’s ponds. complete their development Elizabeth Poskitt the next spring. Woodstock, Oxfordshire, UK Overwintering could bestow a survival advantage over tadpoles that hatch and mature in the This week’s question same year. They may also get a FLYING DOWN THE TRACK ready source of food from the World-class athletes of both pond, as tadpoles are known sexes cover 100 metres in about cannibals (19 April 2014, p 16). 10 seconds. What percentage of David Muir this is spent not touching the Edinburgh, UK ground? And what’s the figure for a 2-hour marathon? Q This reminded me of a childhood episode. Nearly Larry Curley 70 years ago, I kept a large crock Huntingdon, Cambridgeshire, UK

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of rainwater and pondweeds in our yard in Bolton, Lancashire. In spring I used it to follow the progress of collected frogspawn, via tadpoles, into frogs. One year, after our summer holidays, the crock was swarming with four-legged tadpoles at a time when they should long since have departed as frogs. I recalled a book by Enid Blyton about wildlife, which suggested tadpoles needed iodine to mature, presumably because it is used to produce thyroid hormones. Those were the days when medicine cabinets stocked iodine for cuts and grazes, so I