Sommaire pour February 2017 de BBC Science Focus Magazine

Our days are numbered. Between superbugs and supervolcanoes, asteroids and artificial intelligence, the outlook isn’t good if you’re human. In fact, the future isn’t hopeful for most of the planet’s inhabitants. We’re in the throes of Earth’s sixth mass extinction event: the rate of species loss is 100 times larger than expected. It seems almostinevitable (there’s always hope!) that, like the dinosaurs before us, we won’t be a permanent fixture on Earth. But what will happen after we’re gone? How long will it take the planet to recover from the human condition? Find out what’s in store for Earth after humankind has disappeared on p38. Speaking of world-ending events, four years ago this month the Chelyabinsk meteor tore through Russian skies, exploding some 30km above the ground. The meteor’s arrival…

Step aside, Nanook: NASA has announced a Mars base concept that reinvents the igloo. The variable distance between Mars and Earth means astronauts may have to stay on the surface of the Red Planet for many months. That means living quarters are required to keep the crew safe from wildly varying temperatures and radiation. Dubbed the Mars Ice Home, the new structure consists of a doughnut-shaped inflatable living area, surrounded by a dome filled with water. This freezes to form a thick wall of ice, providing more than enough protection from the dangerous levels of cosmic rays that bombard the surface of Mars – and, if split into hydrogen and oxygen, the water can double as fuel for the return rocket. “All of the materials we’ve selected are translucent, so…

What did they do? Researchers from Ohio State University put two types of mole salamander on a treadmill, one type was born via male/ female sexual reproduction, the other asexually from a single female, and ‘encouraged’ them to walk by poking them in the backside. Why did they do that? The team wanted to know more about how the salamanders procreate in order to help with conservation efforts. What did they find? The salamanders that were born via male/female reproduction were willing to walk up to four times as long as their asexually produced counterparts with some individuals trekking for more than 14 kilometres (nine miles). The difference may be due to the asexually produced salamanders having less varied genes and lacking in those responsible for providing them with energy,…

SELFISH SO-AND-SOS Older people who care for others during their dotage live longer than their less helpful counterparts, researchers at the University of Basel have found. The effect is due to the mutual emotional support provided, they say. MIGRATORY BIRDS The early bird doesn’t always catch the worm. Each 1°C rise in global temperature can mean birds reach summer breeding grounds a day early, a team at the University of Edinburgh has found, which may cause them to miss out on food sources.…

 If you’re reading this with the lights on, count yourself lucky. Before long you might be reading it by candlelight, if a new report on Britain’s electricity network is any guide. “WE ALL USE A LOT OF ELECTRICITY WHEN IT’S NOT ACTUALLY NEEDED” The study, which was published by the British Infrastructure Group (BIG), states that the nation’s power supplies can barely cope with current demand, the National Grid’s ‘safety margin’ – the value between demand and available supply – having shrunk to just 0.1 per cent this winter. “By next winter,” the report warns, “the Christmas lights could go out”. How seriously should we be taking all this? Not very, to be frank. First of all, despite its impressive name, the BIG isn’t some authoritative academic think-tank. It’s a…

SYNTHETIC VIRUS With millions of deaths chalked up to natural viruses like smallpox, influenza, HIV and Ebola, it’s unsurprising that experts see an engineered virus as one of the key existential threats to humans. The first synthetic virus was created in 2002, and with the genomes of over 3,000 viruses available online, it may only be a matter of time until one is deliberately released. CLIMATE CHANGE The rate at which humans are altering Earth’s atmosphere is unprecedented, and will have dire consequences unless it is slowed. As the planet heats up, vast swathes of the world will become uninhabitable, leading to mass migration and conflict. Harvests will fail and the oceans will empty of fish. With nothing to eat and nowhere to live, it’s hard to see us surviving…

MOST VIRUSES ( EG . FLU ) INFECTION First of all, the virus infects a host cell. Its protective protein coat breaks down and the virus releases its genes. HIJACK! The virus then takes over the cell machinery that makes genes and proteins. The virus forces it to copy its own genes and make viral proteins. DUPLICATION New viruses will be assembled inside the host cell. Eventually, they will break out and go in search of new hosts to infect. RETROVIRUSES ( EG . HIV ) INFECTION The virus infects a host cell. Its protein coat is broken down and the viral genes (in the form of a DNA-like molecule called RNA) are released into the cell. INSERTION In the cell, the viral RNA uses an enzyme called reverse transcriptase…

CORE ISSUES There is no way for us to dig down to the Earth’s core to take a peep at what’s inside – it’s just too far away (and too hot!). Instead, researchers have to use seismometers and clever measurements to establish the composition of our planet’s interior. When the pioneering science fiction writer Jules Verne wrote Journey To The Centre Of The Earth in 1864, he probably knew that his plot was pure fantasy. Verne’s characters Otto, Axel and their guide Hans, only made it a few miles down, but the idea that anyone could even contemplate travelling to the Earth’s core had been dismissed before Victorian times. Even today, the furthest we’ve ever drilled into the Earth is around 12km, while the distance to the centre is over…

1. Almost all the gold present in Earth’s crust today was delivered by asteroid impacts four billion years ago. Since then, it has been buried under lava flows and other rock strata. 2. Gold is one of the least reactive elements, but it will dissolve very slightly in water. There are about 20g of gold dissolved in every cubic kilometre of seawater. 3. This dilute gold solution seeps into many rock formations as groundwater. However the concentration, just 10 parts per quadrillion, is far too low to make mining economical. 4. Earthquakes force open cracks and the sudden pressure drop precipitates out the gold. Over millions of years, repeated earthquakes build up veins. Eighty per cent of the world’s gold deposits were formed this way.…

KAT ARNEY Kat Arney has a PhD in developmental biology, making her the perfect expert to investigate the viruses that have shaped our evolution. p48 RITA CARTER Every week there is some new gadget or supplement that promises to make you smarter. Brain expert Rita uncovers the methods that really work. p54 DUNCAN GEERE Experts are sure that we’ll go extinct. Science writer Duncan reveals how Earth will cope without us, and takes a look at the legacy we’ll leave behind. p38…

 Say goodbye to your reading glasses. Researchers at Japan’s RIKEN Centre for Developmental Biology have restored vision in mice with end-stage retinal degeneration – the leading cause of irreversible vision loss and blindness in elderly humans – by transplanting retinal tissue grown using stem cells. “VISUAL FUNCTION COULD BE RESTORED TO SOME DEGREE” Patients with conditions such as age-related macular degeneration and retinitis pigmentosa lose vision as a result of damage to the outer layer of light-sensitive photoreceptor cells in the eye. There is currently no cure for this, only therapies aimed at stopping the progression of vision loss. The team genetically reprogrammed skin cells taken from adult mice to an embryonic, stem cell-like state, and then converted these into retinal tissue. When transplanted into mice with end-stage retinal degeneration,…

What’s that? A Netflix drama set in a medieval Italian monastery? Way off. It’s a newly discovered organ found hiding in plain sight in the human digestive system by researchers at Limerick University Hospital. What is it? It’s a group of folded tissues that connects the intestines to the wall of the abdomen. For hundreds of years it was thought to be made up of several sections, but new research has found it is a single, continuous structure. What does it do? All we know so far is that it carries blood between the intestine and the rest of the body, and helps keep the intestine in the right place. So what’s next? The researchers now want to establish the exact function of the organ so that they can identify…

 If you were to travel back tens of thousands of years in time and look up, you may well see a sky full of mini moons. “OUR MOON MAY BE THE LATEST IN A LONG LINE OF MOONS THAT ORBITED EARTH IN THE PAST” Researchers from the Technion-Weizmann Institute of Technology have proposed a theory suggesting that our current Moon may be the latest in a long line of moons that orbited Earth in the past, each created by an impact from giant asteroids. “Our model suggests that the ancient Earth once hosted a series of moons, each one formed from a different collision with the proto-Earth,” said researcher Hagai Perets. “It’s likely that such moonlets were later ejected, or collided with Earth or each other to form bigger moons.…

It looks like this dinosaur just moved up the pecking order. The discovery of several fossils belonging to a small ostrich-like dinosaur called Limusaurus inextricabilis(inextricable mud lizard) has given researchers a clue to the origin of modern birds’ beaks. A total of 19 skeletons of the dinosaur have been found in mud traps in China’s Xinjiang province. They have been dated to about 159 million years ago, during the Jurassic Period. With the unusual luxury of comparing remains of all ages, from baby dinosaurs to adults, a team from China and the US has pieced together a remarkable change that occurred as Limusaurus grew up. They found that the young dinosaurs had teeth, but by the time the animal reached its adult size of 1.5 metres in length, all of…

2 DAYS Without active maintenance and pumping, New York City’s subways flood with water and become impassable. 7 DAYS Fuel runs out at the emergency generators that pump coolant into nuclear power plants. Approximately 450 reactors around the world begin to melt down. 1 YEAR Human head and body lice go extinct, while cockroaches in cities at temperate latitudes freeze to death. Domestic and farm animals perish in enormous numbers. 3 YEARS Pipes burst in colder regions, flooding cities with water. Buildings lose structural integrity as they expand and contract with temperature changes. 20 YEARS The Panama Canal closes, rejoining North and South America. Many crops disappear, outcompeted by wild varieties. 300 YEARS Most of the world’s bridges fall. Dams silt up and overflow, washing away entire cities. Suburbs become…

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Longitudinal waves These waves consist of a series of compressions and relaxations in the direction of travel, like a slinky spring given a push along its length. Examples include sound and P-waves. Refraction When a wave hits the boundary between two materials, travelling at an angle, it changes direction. Light waves, for instance, are refracted when passing between water and air, making a straight object appear bent. Seismology The study of earthquakes. Analysis of how different types of seismic wave travel through the Earth has allowed us to piece together our planet’s inner structure. Torsion balance This apparatus consists of a bar, suspended from a frame by a twisty fibre. As the bar moves sideways, it applies a force to the fibre – the further it twists, the greater the…

“WHY WERE PLANES LEAVING WHITE RIBBONS ON ONE DAY WHEN THEY HADN’T ON THE PREVIOUS DAYS?” At the time of writing this column, there have been several beautifully clear days, which have been cold and frosty at ground level with stunningly blue skies above. But on one of those days, the bright, clear sky was decorated with crisscrossing white lines: contrails from aircraft. For me, wandering along by the river at ground level, the conditions on that day seemed exactly the same as the previous ones. So what had changed up in the atmosphere? Why were aircraft leaving these elegant white ribbons on one day when they hadn’t on the previous days? The conditions in which the aircraft fly are harsh and unforgiving. Cruising altitude is about 10km, where each…

1. Space Shuttle Program Date: 1981-2011 Cost: $199bn 2. International Space Station Date: 1998-2020 Cost: $160bn (estimated) 3. Apollo Space Program Date: 1961-1972 Cost: $109bn 4. SLS and Orion (NASA’s replacement manned rocket and capsule) Date: 2014-2018 Cost: $23bn (estimated) 5. Global Positioning System (GPS) Date: 1978-present Cost: $12bn 6. Hubble Space Telescope Date: 1990-present Cost: $10bn 7. Salyut 6 Date: 1977-1982 Cost: $9bn 8. James Webb Space Telescope Date: Scheduled for 2018 Cost: $8.8bn (estimated) 9. Galileo (Europe’s GPS) Date: 2016 Cost: $6.3bn (estimated) 10. GLONASS (Russia’s GPS) Date: 1982-present Cost: $4.7bn *(Figures in billions of US dollars, adjusted for inflation)…

“This study is exciting because it shows that a complicated part of central nervous system, such as the retina, could potentially be regenerated from something as simple as a skin cell. Furthermore, the engineered retinal tissue appears to be able to make connections to the brain after transplantation. Clinical treatments are still a long way off, but for patients with retinal degeneration, this provides some hope for the future.”…

 The grunts, barks and wahoos of baboons contain distinct vowel-like sounds similar to human speech, suggesting language may have begun to evolve 25 million years ago. “BABOONS PRODUCE FIVE SOUNDS THAT HAVE CLOSE SIMILARITIES WITH VOWEL SOUNDS USED IN HUMAN SPEECH” After analysing 1,335 spontaneous vocalisations produced by 15 male and female Guinea baboons in different social contexts, researchers from Grenoble Alpes University in France found that baboons produce five sounds that have close similarities with vowel sounds used in human speech. Humans form each vowel by precisely controlling the tongue’s position in the vocal tract. It was previously thought that the voice box of non-human primates such as baboons was too high in their necks to produce the distinct vowel sounds found in human languages. This would mean language…

STRESS CAN MAKE DOGS GO GREY It’s not only highly strung humans who are prone to the ‘salt and pepper’ look. A stressful life can also make your pooch’s muzzle turn grey, researchers from Northern Illinois University have found. AFTERNOON NAPS COULD IMPROVE THINKING AND MEMORY Having a quick afternoon doze may not seem like the best way to impress your boss, but it may help improve your work. Getting 60 minutes’ shuteye in the afternoon can make your brain perform as if it were five years younger, a team at the University of Pennsylvania has found. ANTARCTIC ICE IS ON THE MOVE A giant chunk of ice the size of Norfolk could be about to shear off from the Larsen C ice shelf, according to satellite observations by the…

French start-up Uzer was showing off Eugene, a smart kitchen bin that uses a barcode scanner to encourage you to recycle product packaging; it can also add the item to your next online shopping order. Also on show was Oombrella – an umbrella equipped with air pressure, temperature, humidity and light sensors that gives you up to 15 minutes’ notice of imminent rain. Because we all have our brollies out when it’s dry… L’Oreal was at CES demonstrating Hair Coach, a smart hairbrush with a built-in microphone, gyroscope and altimeter that listens for the sound of split ends breaking and tells you off (via Bluetooth and an app) for getting your brushing technique wrong. But perhaps our ‘favourite’ was Kissenger– a prototype silicon iPhone add-on that uses pressure sensors and…

The day of 15 February 2013 was a day like no other, and one I will never forget. Potentially hazardous asteroids were firmly on my mind because that evening the space rock 2012 DA14 was due to make an incredibly close pass of our planet. It measured about 45m across (half a football pitch) and was going to zip by Earth 10 times closer than the Moon. There was no danger of it hitting the Earth – its orbit was well known. Nonetheless it was a timely reminder of the perils of the Solar System’s asteroid population. I had written an article about 2012 DA14 that was attracting a fair amount of readers on The Guardian’s website. Then I got an early morning phone call from one of the newspaper’s…

HENRY CAVENDISH (1731-1810) This English scientist used a torsion balance to measure the gravitational attraction between heavy balls, deducing Earth’s density. 1798 Henry Cavendish publishes the results of his experiment that gives the first figure for the density of the planet. This figure proves sufficiently high that it is very unlikely that the Earth is hollow. JOHN MILNE (1850-1913) English geologist who, with James Ewing and Thomas Gray, invented the horizontal pendulum seismograph, making discoveries about the core possible. 1906 Richard Oldham, in retirement, makes use of the data on arrival times of seismic waves at different points on the Earth’s surface to deduce that planet Earth has a liquid core. RICHARD DIXON OLDHAM (1858-1936) Dublin-born geologist who identified the main wave types on seismograph recordings. He deduced that the…

DR ALASTAIR GUNN Astronomer, astrophysicist ALEXANDRA CHEUNG Environment/ climate expert DR PETER J BENTLEY Computer scientist, author PROF ALICE GREGORY Psychologist, sleep expert PROF MARK LORCH Chemist, science writer CHARLOTTE CORNEY Zoo director, conservationist DR HELEN SCALES Marine biologist, writer DR CHRISTIAN JARRETT Neuroscientist, writer EMMA DAVIES Heath expert, science writer LUIS VILLAZON Science/tech writer DR AARATHI PRASAD Biologist, geneticist PROF ROBERT MATTHEWS Physicist, science writer How many UK spiders are actually dangerous? JULIA REYNOLDS, MILTON KEYNES Essentially, none. There are three common spiders in the UK that are capable of biting you: the cellar spider, the woodlouse spider and the false widow spider. Their bites are painful and have been known to cause swelling for a few hours. In 2014 a 60-year-old woman died after being bitten by a…

On the night of 23 September 1846, the German astronomer Johann Galle noticed an object in the constellation Aquarius which didn’t appear on the latest star maps. Its disc-like appearance suggested it was a new planet – a conclusion confirmed the following night by its movement relative to the distant stars. Galle had discovered Neptune, but it was no accident. He had been asked to examine that patch of the night sky by Urbain Le Verrier, a brilliant French theoretician who had been examining strange effects in the orbit of Uranus, and concluded it was being affected by an unseen planet. But just as Galle and Le Verrier were being hailed for their discovery, British astronomers claimed a young Cambridge mathematician, John Couch Adams, had made similar calculations, and that…