We finally know how whole planets grow from tiny clumps of dust

dust clouds in space

Planets in the making?

NASA/JPL-Caltech

Electricity may be more important to making planets than we thought. We aren’t sure how tiny particles come together to build baby planets, but dropping glass beads from the top of a tall tower has shown that it may be with some help from static electricity.

The very first seeds of planets are made of micrometre-sized grains of dust, which bump into one another as they orbit a star and stick together in fluffy clumps. As more and more tiny grains stick together, the clumps start to compact, until they are no longer fluffy and start to bounce off one another like billiard balls instead of sticking. This happens when the clumps are millimetres across and is called the bouncing barrier.

In order to build a planet, those millimetre-sized dust bunnies have to overcome the bouncing barrier and get bigger. It has been suggested in the past that this may be enabled by static electricity – as the dust particles collide and rub together, they gain electric charges that can encourage them to stick together.

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Tobias Steinpilz at the University of Duisburg-Essen in Germany and his colleagues investigated this using the Bremen drop tower, a hollow turret about 120 metres high that acts as a vacuum chamber in which falling objects behave like they would in the microgravity of space.

They used the tower’s built-in catapult to throw a chamber containing 0.4-millimetre glass beads up towards the top of the tower, then allowed it to fall, watching it with a high-speed camera installed within the falling chamber. They found that the beads did gain electrical charge from static electricity and stuck together in clumps up to several centimetres across.

“When you have charged particles and they form centimetre-sized clusters like we observed in our experiments and our simulations, we can close this gap in size caused by the bouncing barrier,” says Steinpilz. The particles are then free to clump together even more with the help of gravity and eventually become planets.

Journal reference: Nature Physics, DOI: 10.1038/s41567-019-0728-9

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The race to find wild relatives of food plants before it’s too late

The Millennium Seed Bank

Kew’s Millennium Seed Bank

Kew

Seeds from 400 wild relatives of food crops such as bananas, rice and aubergines have been collected to save their valuable genetic diversity before it is lost. These could be crucial for maintaining food production as the climate changes.

“This was a massive effort,” says Hannes Dempewolf at the Crop Trust in Bonn, Germany, which led the 10-year project. The next step is to use the wild plants to breed new varieties of crops with traits such as drought or disease resistance.

That is important because we know that if farmers keep cultivating the same varieties in the same way, yields can plummet as pests and diseases evolve and spread. For instance, rice yields in Asia were hit by the rice grassy stunt virus in the 1970s, says Dempewolf. Resistant varieties were then created by crossing rice with a wild relative. Now the virus is becoming a problem again. It is a constant battle, a bit like walking up an escalator the wrong way.

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What is more, the speed at which such issues arise is accelerating because of climate change, which is already hitting food production. “You have to walk faster to stand still,” says Alisdair Fernie of the Max Planck Institute for Molecular Plant Physiology in Germany, who wasn’t involved in the project.

Treasure trove

This is why the Crop Trust set out to save the genetic diversity present in wild plants. “Since 2013, more than 12 million seeds have been collected,” says Chris Cockel at Kew’s Millennium Seed Bank in the UK. These come from about 5000 locations of the 400 crop relatives.

Plants sampled include a wild relative of the carrot, one that grows in salty water, an oat relative resistant to the powdery mildew that devastates normal oats, and a kind of bean that tolerates high temperatures and drought.

The seeds are now being sent to non-profit breeding organisations around the world. Some will also be stored in seed banks, including the Svalbard Global Seed Vault in the Arctic.

In some cases, the collectors arrived in the nick of time. In Ethiopia, samples were taken from a region that will soon be flooded by a dam. In Chile, they found only one site where a wild barley was still growing after a massive fire destroyed most of its habitat.

Sometimes they were too late. In Costa Rica, collectors found only sugar cane plantations and urban sprawl where a wild rice used to grow.

Read more: Domesticating tomatoes took millennia – we can now redo it in 3 years

“We have made incredible progress,” Marie Haga, director of the Crop Trust, said in a statement. “But there is more to be done, and as threats to the world’s biodiversity mount, this work is more urgent than ever.”

As well as improving existing crops, we should also be conserving and domesticating wild plants that are rarely grown and eaten, says Fernie. At present the world is over-reliant on a handful of crops, some of which are grown where conditions aren’t ideal.

In these places, domesticating local plants – which can now be done very rapidly – could allow more food to be grown in a more sustainable way. But for farmers to diversify the plants they grow, consumers will have to diversify their diets.

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Controversial DNA screening technique used for at least one pregnancy

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DNA can be taken from IVF embryos and analysed

PASCAL GOETGHELUCK/SCIENCE PHOTO LIBRARY

A company called Genomic Prediction has confirmed that at least one woman is pregnant with embryos selected after analysing hundreds of thousands of DNA variants to assess the risk of disease. It is the first time this approach has been used for screening IVF embryos, but some don’t think this use of the technology is justified.

“Embryos have been chosen to reduce disease risk using pre-implantation genetic testing for polygenic traits, and this has resulted in pregnancy,” Laurent Tellier, CEO of Genomic Prediction, told New Scientist. He didn’t say how many pregnancies there were, or what traits or conditions were screened for.

While a few genetic mutations lead to serious disorders, the effect of most DNA changes is much less clear-cut. A particular mutation may only very slightly raise the risk of heart disease or cancer, for instance. Geneticists attempt to work out the overall effect of thousands of mutations by sequencing people’s DNA and calculating a so-called polygenic risk score, but there are big questions about how accurate or useful these are.

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Genomic Prediction, which is based in New Jersey, is the first company to offer polygenic risk scores for embryos rather than adults, including an option to screen out embryos deemed likely to have very low IQ.

Using polygenic risk scores to screen embryos is controversial. “It is inappropriate to use pre-implantation genetic diagnosis to screen out polygenic risk factors for things like cardiovascular disease,” says Frances Flinter at Guy’s and St Thomas’ NHS Foundation Trust in the UK. “I think it’s a misuse of the technology.”

Such screening places undue emphasis on genetics when it isn’t the biggest factor, she says. For most of us, our risk of heart disease is determined by our diet, whether we smoke, how much exercise we take and so on.

“It’s completely different from using pre-implantation genetic diagnosis to select out embryos at high risk of a very serious disorder, when we can predict with complete accuracy whether or not those embryos will be affected,” says Flinter.

But Steven Hsu, one of the founders of Genomic Prediction, says polygenic scores reveal that a few people – those with the top 3 per cent of scores – have a dramatically higher risk of, say, breast cancer or heart disease. The company’s tests aim to identify these outliers.

“These results are very new,” says Hsu. “A typical pre-implantation genetic diagnosis expert who focuses on single gene conditions might not be aware of how strong the polygenic predictions can be.”

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Robot debates humans about the dangers of artificial intelligence

Project Debater

Project Debater argued both for and against the benefits of artificial intelligence

IBM

An artificial intelligence has debated the dangers of AI – narrowly convincing audience members that the technology will do more good than harm.

Project Debater, a robot developed by IBM, spoke on both sides of the argument, with two human teammates for each side helping it out. Talking in a female American voice to a crowd at the University of Cambridge Union on Thursday evening, the AI gave each side’s opening statements, using arguments drawn from more than 1100 human submissions made ahead of time.

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On the proposition side, arguing that AI will bring more harm than good, Project Debater’s opening remarks were darkly ironic. “AI can cause a lot of harm,” it said. “AI will not be able to make a decision that is the morally correct one, because morality is unique to humans.”

“AI companies still have too little expertise on how to properly assess datasets and filter out bias,” it added. “AI will take human bias and will fixate it for generations.”

Read more: The hardest thing about robots? Teaching them to cope with us

The AI used an application known as “speech by crowd” to generate its arguments, analysing submissions people had sent in online. Project Debater then sorted these into key themes, as well as identifying redundancy – submissions making the same point using different words.

Project Debater

Project Debater summarised arguments put forward by humans

IBM

The AI argued coherently but had a few slip-ups. Sometimes it repeated itself – while talking about the ability of AI to perform mundane and repetitive tasks, for example – and it didn’t provide detailed examples to support its claims.

While debating on the opposition side, which was advocating for the overall benefits of AI, Project Debater argued that AI would create new jobs in certain sectors and “bring a lot more efficiency to the workplace”.

But then it made a point that was counter to its argument: “AI capabilities caring for patients or robots teaching schoolchildren – there is no longer a demand for humans in those fields either.”

Read more: Want to build robots and invent stuff? Here’s where to start

The pro-AI side narrowly won, gaining 51.22 per cent of the audience vote.

Project Debater argued with humans for the first time last year, and in February this year lost in a one-on-one against champion debater Harish Natarajan, who also spoke at Cambridge as the third speaker for the team arguing in favour of AI.

IBM has plans to use the speech-by-crowd AI as a tool for collecting feedback from large numbers of people. For instance, it could be used by governments seeking public opinions about policies or by companies wanting input from employees, said IBM engineer Noam Slonim.

“This technology can help to establish an interesting and effective communication channel between the decision maker and the people that are going to be impacted by the decision,” he said.

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People share fake news online even when they can tell it’s not true

fake news

We spread fake stories even though we can detect them

Thomas Trutschel/Getty

The spread of fake news on social media has been a problem for years. But there may be a simple solution to stop people sharing inaccurate information.

Gordon Pennycook at the University of Regina in Canada and colleagues have found that people can identify fake news easily, but may unwittingly share misinformation on social media because they aren’t thinking analytically.

The researchers presented more than 2500 people from the US with real headlines and images taken either from mainstream news stories or from a cache of stories that …

General election 2019: Who is strongest on climate change action?

Protesters at the YouthStrike4Climate student march pass through Oxford Circus on April 12, 2019 in London, United Kingdom. Students are protesting across the UK due to the lack of government action to combat climate change.

Climate change is rising up the political agenda

GettyImages-1136454906.jpg

Channel 4 News has confirmed that the world’s first ever TV election debate dedicated to climate change will go ahead this Thursday, giving voters the perfect opportunity to see who has the most credible plan to cut carbon emissions.

But while the leaders of Labour, the Liberal Democrats, the Green Party and the Scottish National Party have promised to attend, Boris Johnson of the Conservatives and Nigel Farage of the Brexit party are still yet to commit. Channel 4 News have said they are willing to “empty chair” leaders who do …

A blue whale’s heart beats just twice a minute when it dives for food

blue whale

The blue whale heart beats slowly when the animal feeds

Image courtesy of the Duke Marine Robotics and Remote Sensing Lab

We have checked the pulse of a wild-living blue whale for the first time, and discovered something remarkable. When blue whales dive for food they can reduce their heart rates to as low as 2 beats per minute. This is well below the rates the large animals were calculated to have. Previous predictions were that the whales would have a resting heart rate of 15 beats per minute.

The finding is particularly extraordinary given that whales have an energetically demanding feeding method, says Jeremy Goldbogen at Stanford University, California. During lunge feeding, a blue whale engulfs a volume of prey-filled water that can be larger than its own body.

From a large inflatable boat in Monterey Bay, California, Goldbogen and his team used a 6-metre pole to attach heart rate monitors to a single blue whale. The monitors were held in place with suction cups. The researchers were then able to monitor the whale’s heart rate for almost 9 hours. They detected heart rates of just 2 to 8 beats per minute hundreds of times.

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The whale dived for as long as 16.5 minutes at a time, reaching a maximum depth of 184 metres, and stayed at the surface for intervals ranging from 1 to 4 minutes. The whale’s heart rate was at its lowest when it was diving for food and shot up after it resurfaced, reaching a peak of 37 beats per minute.

The reduction in heart rate during dives enables whales to temporarily redistribute oxygenated blood from the heart to other muscles needed for lunging, says Goldbogen. Whales then recover upon resurfacing by dramatically increasing their breathing and heart rate, he says.

These results demonstrate “the quite extraordinary level of flexibility and control that these diving mammals have over their heart rate and blood flow”, says Sascha Hooker at the University of St Andrews, UK.

Recent technological advances have enabled these kinds of readings to be collected from free-living whales, says Hooker. “These are opening the door to a much greater understanding of how these animals are able to perform some quite amazing feats of diving and exercise,” she says.

Journal reference: PNAS, DOI: 10.1073/pnas.1914273116

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Jupiter’s Great Red Spot is healthy despite looking like it’s dying

Jupiter red spot

Jupiter’s Red Spot is in better shape than we thought

NASA/JPL-Caltech/SwRI/MSSS/Kevin M. Gill/CC BY 3.0

Jupiter’s giant storm, the Great Red Spot, may not be dying any time soon. It seems to have been unravelling for decades, but this is probably down to the movement and shredding of clouds rather than a sign that the storm is abating.

Concerns have been mounting that the Great Red Spot might disappear. Once it was big enough for almost three Earth-sized planets to fit inside it – now it can hold little more than one. Although we know the iconic storm has been shrinking since 1878, the pace of this seems to have picked up since 2012, leading to reports that it could be nearing its demise.

What’s more, photos of Jupiter captured earlier this year by the spacecraft Juno showed red “flakes” measuring 100,000 kilometres across breaking off from the Great Red Spot.

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But this flaking isn’t actually a sign of the storm breaking apart and dying, says Philip Marcus at the University of California, Berkeley, who presented the findings today at a meeting of the American Physical Society in Seattle.

The health of the Great Red Spot has been previously inferred from images of the clouds that sit above its central swirling vortex – shrinking clouds are thought to indicate a shrinking storm. But although the clouds probably affect the vortex, they aren’t crucial to maintaining the storm itself, says Marcus.

Using computer models, he and his colleagues found that the flaking captured by Juno was in fact the effects of a rare event: cyclones that are common in Jupiter’s atmosphere had collided with lumps of cloud that hadn’t yet been pulled into the storm as they passed by. The impact “shattered” the clouds, which appear red because they sit above the storm and are therefore exposed to more of the sun’s UV radiation. This gives the impression that parts of the Great Red Spot are coming apart.

Marcus says he was surprised by how easy it was to simulate the flaking, which “cried out for explanation”.

“It’s wonderful to see serious attempts at numerical simulations being brought to bear on this complex topic,” says Leigh Fletcher at the University of Leicester, UK. We should be careful about making assumptions based on photos alone when we still don’t fully understand the storm’s environment, he says.

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