BBC Science Focus Magazine的April 2021目录

Etna awakens CATANIA, SICILY ITALY Mount Etna has done it again. In February, Europe’s most active volcano erupted, releasing an estimated 40 million cubic metres of volcanic material and a 1,500- metre-high ash cloud. “It’s Etna’s largest eruption since 2000 – and is very, very spectacular,” says Boris Behncke, a volcanologist at Italy’s National Institute of Geophysics. But while apocalyptic in appearance, the 3,300m-high volcano poses little danger to the local population and buildings (including the Mother Church of Belpasso, pictured). Etna’s magma stream cools and solidifies well before reaching any towns. And unless crushed into dust by vehicles, any ash is too large to inhale. “The volcano’s regular eruptions are relatively safe and normal,” says Becker. “In fact, the ash can be a valuable resource, used as a fertiliser…

Size matters Teenage T. rexes distort dinosaur size diversity p22 Clearly useful The high-tech contact lens that monitors your eye health p23 Off with my head! Sea slugs lose their heads... but live on to grow new bodies p24 For the first time, scientists using the Hubble Space Telescope have found evidence of volcanic activity reforming the atmosphere on a rocky planet around a distant star. The planet, Gliese 1132 b, is located 40 light-years away in the constellation Vela and has a similar density, size and age to Earth. It was first discovered in 2015 by the MEarth-South telescope array in Chile and appears to have begun life as a so-called sub-Neptune planet – a gaseous world with a thick atmosphere. It’s thought Gliese 1132 b initially had a…

Cuttlefish not only possess three hearts and a 360° field of vision, but also a strong sense of self-control, according to a new study. As research from the Marine Biological Laboratory in Massachusetts shows, when presented with the option of eating a raw king prawn immediately or a grass shrimp (their preferred food) after a short delay, the marine molluscs chose the latter option. In fact, while all six cuttlefish tested could tolerate a delay in feeding of 15 seconds, some were prepared to wait 130 seconds. These results indicate the cephalopods can delay gratification like large-brained vertebrates, such as chimps. The cuttlefish that could wait longest before eating its favourite food also performed better in a cognitive test, learning faster to associate a visual cue with a food reward.…

Researchers from Purdue University in the US have successfully fitted stretchable biosensors to a commercially available contact lens for the first time. The breakthrough will enable them to gather vital information about patients’ eye health without discomfort, or the need for anaesthetics or other intrusive surgical measures. “This technology will be greatly beneficial to the painless diagnosis or early detection of many ocular diseases including glaucoma,” said lead researcher Prof Chi Hwan Lee. “Since the first conceptual invention by Leonardo da Vinci, there has been a great desire to utilise contact lenses for eye-wearable biomedical platforms.” Fitting sensors or other electronics to commercial soft contact lenses has previously proven difficult due to the complex fabrication techniques required to embed them into a flexible, curved contact lens. Now, a multidisciplinary group…

WHAT DID THEY DO? Rebecca Poulsen, a DJ and neuroscientist at the University of Queensland, Australia, played MC Hammer’s 1990 floor-filler U Can’t Touch This to a group of juvenile zebrafish and monitored their brain activity using a special microscope. WHY DID THEY DO THAT? She wanted to investigate how the fishes’ young brains responded to a range of different sounds, tones and frequencies, and to study how their sound-processing ability changes as they grow into adults. WHAT DID THEY FIND? They found that the fish were able to hear a much broader range of frequencies than previously expected and that neurons in their brains appeared to be reacting to the beat and vocals of the track.…

After nearly 20 years of development and 16 launch delays, the James Webb Space Telescope (JWST) is almost ready. Set to launch on 31 October 2021, the largest space observatory ever built is set to revolutionise our understanding of the cosmos and help solve some of the Universe’s greatest mysteries. It hasn’t been an easy journey. First conceived 30 years ago as the successor to the Hubble Space Telescope, the ‘Next Generation Telescope’ as the JWST was first known, has survived threats of cancellation, changes of leadership and numerous postponements. Expected to cost $10bn (£7.2bn approx), the JWST (named after NASA’s second administrator James E Webb) is the sixth most expensive space mission of all time. And it’s not surprising: the JWST is brimming with innovation and complexity, is the…

The biggest seamounts, 1,500m and taller, can be spotted from space, even though their peaks don’t show above the surface. Satellites measure slight bulges in the sea surface, caused by the gravitational pull of massive, basaltic mounts that draw seawater in and pile it up above them. Newer satellite sensors capable of spotting smaller peaks, 1,000m and taller, will soon add to the global count of seamounts. To find smaller and deeper seamounts – and to build accurate 3D maps – requires multi-beam sonar devices that scan the seabed using sound. These are either ship-based or are fixed to deep-diving, autonomous robots. “It’s a really interesting process,” says Dr Astrid Leitner, who has searched for ultra-deep seamounts in the central Pacific. “You’re multi-beaming, then you have to clean up the…

Oranges, reds, yellows... a kaleidoscope of colour. It was like walking in the Alps in autumn. Truly amazing.” Israeli geologist Boaz Langford is describing one of the vast caverns in Dark Star – a huge cave system tucked inside the Baisun- Tau mountain range in an isolated region of Uzbekistan. Langford was part of the international team of scientists and cavers who explored the system in 2014. “In another branch there are frozen lakes; elsewhere, huge waterfalls. The variety of sights is incredible. Every area is different. Dark Star is like no other. Totally unusual. I’m a scientist, and not very religious, but there is something spiritual about that place.” Political instability and its remote location have kept the depths of Dark Star (named after a 1974 sci-fi comedy film)…

*1AU = APPROX. 150,000,000KM Take a moment to imagine a giant lump of metal, 25 times larger than Mount Everest, floating through space. Finding it difficult to conjure an image? Don’t worry, nobody can. That’s because no one has ever seen such an object up close before. But five years from now, all will be revealed. January 2026 is the target date for a new NASA spacecraft to arrive at an asteroid called Psyche. Named after the Greek goddess of the soul, Psyche was discovered on 17 March 1852 by the Italian astronomer Annibale de Gasparis. It’s one of the most massive bodies in the asteroid belt between Mars and Jupiter. Modern estimates suggest it contains about 1 per cent of all the mass spread across the millions of asteroids…

A spacecraft hurtles out of the Solar System travelling faster than any rocket, probe or instrument we’ve launched into space before. It’s on a daring mission to answer some of the most fundamental questions about the Universe once and for all. “We’ve all been asking them since we were six years old,” says Slava Turyshey from NASA’s Jet Propulsion Laboratory. “Are there other planets? Can we see them? Is there life?” Astronomers have revolutionised our understanding of our place in the Universe over the last quarter of a century. In 1995 they found their first alien planet orbiting a Sun-like star. It whetted their appetites to such a degree that we’ve been hunting them down ever since. At the last count there are over 4,000 of these exoplanets in our…

If the Greenland ice sheet were to melt away, global sea levels would rise an average of six metres, putting almost every coastal city in the world at risk of major flooding. Now, a study of an ice core forgotten for more than 50 years has found this is exactly what happened during a recent warm period that was alarmingly similar to the one we’re headed towards due to human-caused climate change. The core was originally extracted in 1966 from Camp Century, a Cold War military base. The base masqueraded as a science station to provide cover for Project Iceworm – a secret US Army programme to build a network of mobile nuclear missile launch sites beneath the Greenland ice sheet. The military mission failed, but the science team did…

Being cooped up in a tin can that’s flying through space with a bunch of strangers is likely to put a strain on anyone. But now researchers at the University of Pennsylvania have found that weightlessness could reduce astronauts’ ability to recognise emotions. Over 60 days, the researchers had 24 participants spend all their time lying in a bed tilted at a 6° angle towards their heads to simulate microgravity, except for 30 minutes a day in which they were spun on a centrifuge with their head at the centre to mimic artificial gravity. Their cognitive performance was assessed before, during and after the bed rest, using tests that measured differences in their spatial orientation, memory, risk taking, and emotion recognition that were specifically designed to determine the performance of…

On Friday 5 March, Hamish Harding and Victor Vescovo were sealed into Limiting Factor, a two-man submersible, to begin their descent to Challenger Deep – the deepest section of the Mariana Trench, located close to 11km below the surface of the Pacific Ocean. The pair spent almost 12 hours making the round trip to the bottom and back.…

FIRST LIGHT The JWST will be able to look back to around 200 million years after the Big Bang, when the first stars in the Universe formed. The first stars are thought to have been massive giants made of hydrogen and helium, whose short lives ended in the supernovae that created the heavier elements we detect in younger stars today. To see this period in cosmic history, we need sensitive infrared instruments to detect the faint traces of light that have travelled through space and time to reach us. ANCIENT GALAXIES The JWST will also look back to the very first galaxies in the Universe to learn more about their evolution and why there’s so much variety in them. Nearly all the spiral and elliptical galaxies that we see today…

For almost 40 years, our nearest cosmic neighbour, the Moon, was left alone as we looked elsewhere in the Solar System. That changed in 2013, when China’s Chang’e 3 lander touched down on the lunar surface. Since then there’s been an explosion of interest in the Moon. NASA, China and even private companies are racing back to it, with dozens of robotic and human missions being planned. Things are set to get a lot more crowded on the lunar surface over the coming decade, but this time, we’ll be staying. “We know the Moon has potential resources that will be useful for space exploration,” says Ian Crawford, a professor in planetary science from Birkbeck, University of London. “Particularly water ice trapped in the very dark shadows of craters at the…

HOW TO SPOT THE BEEHIVE CLUSTER WHEN: MARCH-APRIL One of the best things to find in early spring, if you have a pair of binoculars, is the Beehive Cluster. Like the Pleiades, the Beehive is an open star cluster, a group of a few thousand relatively young stars (many of them are only 600 million years old, compared to our Sun’s 4.5 billion). These stars are found in the same place because they all developed out of the same huge cloud of gas. At 520-610 light-years away, it’s one of the nearest open clusters to Earth and has more bright stars than most of the other close clusters, such as the Alpha Persei cluster. It can be seen very faintly with the naked eye in dark skies, but is much…

ROB SEDGWICK, DORKING DO ANIMALS HAVE ACCENTS? Some animal communication is entirely hardwired. A moth can’t learn to produce a different mating pheromone, for example. But animals with more complex communication often learn the subtleties of their language by copying those around them. In 1958, researchers at Cambridge University showed that male chaffinch birds reared in isolation would grow up to sing a much simpler song; all the trills and flourishes are apparently learned from other chaffinches. Over time, isolated populations within the same species develop their own regional songs. A 2016 study at Prague University found that yellowhammers introduced to New Zealand from England in the 19th Century were using songs no longer sung by native yellowhammers back home. An accent is more subtle than a whole new song…

ACROSS I Clean land (5) 4 Avoid getting some confectionery (5) 8 Word about your first union contribution (5) 9 Ignorant woman joined conflict to the east (7) 10 Fool removes first slice of bread (3) 11 Returning old king managed to find holy book (5) 12 Overweight, that woman’s relative (6) 14 Excellent landlord is a big character (7,6) 17 Sign of age, finding some bread on the internet (6) 19 Understood one during diplomacy (5) 22 Gamble without diamonds, and get diamonds (3) 23 Cosmetic for musical set (4,3) 24 Bird getting dressed, losing tail (5) 25 Strange omen about small particle (5) 26 Ocean unsuitable for such a vessel (5) DOWN 1 Thrill, following team assistant (8) 2 Argumentative athlete? (5) 3 Bark time, holding single weapon…

Where you left it The February issue’s Explainer (p86) on memory pointed out how it’s all too easy to forget where you left things like your car keys if you don’t pay sufficient attention when you put them down. But there’s a way to solve this problem: decide on specific places to leave these items, then discipline yourself to only leave them in their designated spots. If you live with other people, pick places that your housemates won’t disturb. If you keep putting your ‘loseables’ in these locations, it’ll eventually become a habit and you’ll always know where to find them! Paul Jeffels, Derby PS: I’ve subscribed to BBC Science Focus for years and the ‘How your brain creates reality’ feature (p54, February) is one of the most interesting –…

CHATTERBOXES A study of 800 people carried out at Cornell University found that, on average, they wished that their recent conversations had lasted almost two minutes longer. THE FUTURE The pandemic has made the last year tough for everyone. But there’s at least one silver lining: a survey of 1,000 11- to 17-year-olds, for digital healthcare provider Medicspot, has found that almost half of them are now interested in pursuing a career in STEM. MOTHS The UK’s moths have declined by a third in the last 50 years, a survey by Butterfly Conservation has found. They blame artificial light, pollution and climate change, along with a loss of habitat. CAT ‘OWNERS’ Researchers at Kyoto University had cats watch their owners ask another person for help opening a container. Some people…

Prehistoric heavyweights such as the Tyrannosaurus rex might have outcompeted their smaller rivals while in their teens, leaving medium-sized dinosaurs missing from the fossil record, researchers from the University of New Mexico and the University of Nebraska-Lincoln believe. Palaeontologists have long been puzzled as to why the global diversity of dinosaurs, particularly small- to medium-sized species, is so low. Now, a new study published in the journal Science suggests this may be because the smaller species were outcompeted by adolescent megatheropods (big, bipedal, carnivorous dinosaurs) that were not yet fully grown. Despite growing to the size of double-decker buses, dinosaurs such as the T. rex started life relatively small – about the size of a Chihuahua – on account of having to hatch from eggs. Hence, it’s likely they would…

It’s the sort of thing you’d expect to see in a David Cronenberg film: a species of sacoglossan sea slug is able to live as a detached head for several weeks – long enough for the severed head to grow an entirely new body and a full set of internal organs. The discovery was made entirely by accident by researchers at Nara Women’s University in Japan. A team there was studying the life cycles of sacoglossans, when PhD student Sayaka Mitoh noticed one of the heads was moving around by itself. The head had separated from its heart and body, and immediately afterwards, it started to move about on its own, she said. Within days, the wound at the back of the slug’s head had closed up. Its heart started…

WHAT IS THE UNCANNY VALLEY? The uncanny valley is a point where things like humanoid robots and CGI characters start to give us an eerie feeling. And the reason for that is because they’re not perfect representations of humans – they never quite get there. So, they emit these feelings of terror, unease and unfriendliness. From birth we’re able to detect and analyse faces. And faces play such an important part in our communication. When we start to see things that shouldn’t be there, things that are out of place, we do get that feeling of repulsion. It’s not just appearance, though, it’s in functionality as well. The way robots move, say. If a robot doesn’t move the way we expect it to move, that again gives that feeling of…

“Estimates suggest there are between 30,000 and more than 100,000 seamounts with peaks over 1,500m high” On land, you’d struggle to find a mountain that hasn’t already been climbed. In contrast, in the deep sea there are thousands of unexplored peaks. Seamounts are submerged volcanoes, active or dormant, with foothills planted in the abyss and summits soaring up thousands of metres without breaking the sea surface. These hidden mountains are some of the least known, but most abundant geological features on the planet. They form a fragmented habitat that covers an area rivalling the world’s tropical rainforests. As scientists learn more about seamounts, it’s becoming clear that these dramatic montane seascapes are rich oases of life that play a crucial role across the entire global ocean. ENORMOUS, ABUNDANT AND UNEXPLORED…

Historically, lawless colonisation of a new land has rarely ended well. While there are no indigenous peoples or environments that can be harmed on the Moon, the current state of space law could be setting up future lunar colonists for disaster. Today, the only international law governing space stems from the 1967 Outer Space Treaty that’s overseen by the United Nations. This states that no government can lay claim to the Moon, but failed to foresee that private companies may also want to stake a claim. There’s no discussion of what will happen if two parties want to set up their bases in the same spot. And when it comes to mining, there’s a big grey area over whether the miners would actually be able to claim ownership of the…

NASA’s Psyche mission is currently scheduled to launch in the summer of 2022. This date is critical because the mission needs a gravitational boost from Mars to hoist it into the outer Solar System, and Mars and Earth only come into alignment once every two years. So far, the mission remains on course, despite the problems imposed by the pandemic. AUG 2022 PLANNED LAUNCH The Psyche spacecraft will launch aboard a SpaceX Falcon Heavy in August, during its launch window. This will place it on a trajectory to Mars. MAY 2023 MARS GRAVITY ASSIST Arriving at Mars, Psyche will make a flyby. In the process, it’ll pick up enough orbital energy to propel it to its rendezvous with the asteroid Psyche. JAN 2026 ARRIVAL AT PSYCHE Following a 100-day approach…

HOW IS ARTIFICIAL MEAT MADE? Also known as cultured or cell-based meat, artificial meat is grown from animal cells in a laboratory. Start-up companies have grown artificial beef, pork, chicken and even fish. However, none is commercially available yet. There are different ways to grow artificial meat, but most use adult stem cells from a live animal. For beef, a tiny muscle sample is taken from a cow, under local anaesthesia. The muscle is chopped into smaller pieces, using enzymes to digest it and release the stem cells. In a huge vat called a bioreactor, the stem cells are immersed in a broth containing salts, vitamins, sugars and proteins, as well as growth factors. The oxygen-rich, temperature-controlled environment allows cells to multiply dramatically. The stem cells then differentiate into muscle…

NATURE IS GOOD FOR YOU Studies prove this beyond doubt. We see biological markers of stress reduce and improvements in psychological wellbeing when people spend time in the natural world. Nature helps us to unwind after a difficult day. It can lead to an increase in positive emotions and a reduction in negative thought patterns, such as rumination. It’s good for the environment too. Research suggests that people who feel more connected to nature are more likely to develop pro-environmental behaviour. YOU DON’T NEED TO GO FAR Nature is all around. Just look outside or open a window. Be purposeful. Take the time to stop, and really look and listen. You’ll start to notice things that you never spotted before. LISTENING TO NATURE IS LIKE A SUPERPOWER When you walk…