More stories

  • in

    Mini-Neptunes may become super-Earths as the exoplanets lose their atmospheres

    Mini-Neptunes and super-Earths may have a lot more in common than just being superlatives.

    Four gaseous exoplanets, each a bit smaller than Neptune, seem to be evolving into super-Earths, rocky worlds up to 1.5 times the width of our home planet. That’s because the intense radiation of their stars appears to be pushing away the planets’ thick atmospheres, researchers report in a paper submitted July 26 at arXiv.org. If the current rate of atmospheric loss keeps up, the team predicts, those puffy atmospheres will eventually vanish, leaving behind smaller planets of bare rock.

    Sign Up For the Latest from Science News

    Headlines and summaries of the latest Science News articles, delivered to your inbox

    Thank you for signing up!

    There was a problem signing you up.

    Studying how these worlds evolve and lose their atmospheres can help scientists understand how other exoplanets lose their atmospheres. And that, says astronomer Heather Knutson of Caltech, can provide intel on what types of planets might have habitable environments. “Because if you can’t keep an atmosphere,” she says, “you can’t be habitable.”

    Knutson and her colleagues’ new study bolsters a previous suspicion. Earlier this year, the same researchers reported that helium seemed to be escaping the atmosphere of one these mini-Neptunes. But the team wasn’t sure if their discovery was a one-off. “Maybe we just got very lucky for this one planet, but every other planet is different,” says exoplanet researcher Michael Zhang, also of Caltech.

    So the team looked at three more mini-Neptunes orbiting other stars and compared those worlds to the first planet they had observed. Each of these planets occasionally blocks some of the light from its star (SN: 7/21/21).  Zhang, Knutson and colleagues tracked how long each planet blocked its stars’ light and how much of that starlight was absorbed by helium enveloping the planets. Together, these observations let the team measure the sizes and shapes of the planets’ atmospheres.

    “When a planet is losing its atmosphere, you get this big, sort of cometlike tail of gas coming out from the planet,” Knutson says. If the gas instead is still bound to the planet — as is the case for Neptune in our solar system — the astronomers would have seen a circle. “We don’t fully understand all the shapes that we see in the outflows,” she says, “but we see they’re not spherical.”

    In other words, each planet is steadily losing its helium. “I never would have guessed that every single planet we looked at, that we would see such a clear detection,” Knutson says.

    The astronomers also calculated how much mass those exoplanets were losing (SN: 6/19/17). “This mass loss rate is high enough to strip the atmospheres of at least most of these planets, so that some of them, at least, will become super-Earths,” Zhang says.

    These rates, though, are just snapshots in time, says Ian Crossfield, an exoplanet researcher at the University of Kansas in Lawrence who was not involved with this work. For each planet, “you don’t know exactly how it’s been losing atmosphere throughout its entire history and into the future,” he says. “All we know is what we see today.” Even with such open questions, he adds, the idea that mini-Neptunes turn into super-Earths “seems plausible.”

    Theories and computer simulations of how planets form and lose their atmospheres can help fill in some of the blanks on individual planets, Crossfield says.

    Measurements of more mini-Neptunes will also help. Zhang plans to observe another handful. In addition, “we’ve already looked at one more target, and that target also has a pretty strong escaping helium [signal],” he says. “Now we have five for five.” More

  • in

    How to make a delicious chilli hot sauce by harnessing fermentation

    It might sound daunting, but fermentation can be used to make hot sauces packed with flavourful compounds, says Sam Wong

    Humans

    3 August 2022

    By Sam Wong
    Shutterstock/Fotema
    HOT sauces are popular all over the world. Many are produced by fermentation, using microorganisms to add depth of flavour and create sauces offering more than just a kick of chilli heat.
    The burning sensation comes from capsaicin, a molecule that activates heat receptors. As Clare Wilson explained in her science of gardening column a fortnight ago, Capsicum plants may have evolved the ability to produce capsaicin to deter mammals from eating them, but our species has developed a perverse taste for the pain it brings.
    If you are following Clare’s tips for growing chillies at home, you might … More

  • in

    Untangling life's molecular mysteries using AI is a welcome advance

    DeepMind
    “It has not escaped our notice…” With those famous words published in 1953, James Watson and Francis Crick described the fundamental genetic significance of the double-helix structure of DNA, based on work by Rosalind Franklin. It was a pivotal moment in biology, allowing us to understand for the first time how living organisms store the recipes for making proteins – the molecular machines that do most of the hard work in our bodies – and pass them down the generations.
    Another major step forward came in 2001, with the draft sequence of almost the entire human genome. That revealed the … More

  • in

    Pink Sauce provokes social media savaging

    Feedback investigates the powerful reach of a proprietary condiment, while also looking into the chess robot that broke its opponent’s finger – and a disturbing update to the latest Sims video game

    Humans

    3 August 2022

    Josie Ford
    Dressing down
    Time for elevenses – and what could be nicer to go with this cuppa than a cucumber sandwich slathered in Miami chef Carly Pii’s proprietary Pink Sauce?
    Pii’s product launch wasn’t the smoothest, according to the Los Angeles Times. A couple of misprints on her labelling left purchasers with a 444-gram bottle that provided “444 servings”. Just how powerful is this condiment? Too powerful for some: the dragon fruit that lend the sauce its tang and lurid colour act rather like beetroot, and this distressed some unsuspecting consumers, come their next bowel movement. Pii duly adjusted her formula, … More

  • in

    Nightmare Fuel review: The psychology that underpins horror films

    Scary movies really get under our skin, but why is this the case and how do film-makers know what will scare us? A new book has some interesting answers

    Humans

    3 August 2022

    By Elle Hunt
    Tuan Tran/getty images
    Nightmare Fuel
    Nina Nesseth
    Tor Nightfire
    I HAVE friends who are so afraid of sharks that they won’t swim in the sea – no matter how enclosed the harbour, or full the beach. When I went cage diving with great whites last year, they were appalled. Yet at the same time, I noticed, they couldn’t wait to see the footage.
    This illustrates the idiosyncratic and inexplicable nature of fear. While our desires tend to run along consistent lines – love, happiness, health and wealth – what frightens us is often intensely personal and even perverse.
    So how do film-makers petrify their audiences? And … More

  • in

    Don't Miss: Nope, a chilling new sci-fi thriller from Jordan Peele

    Universal Pictures
    Watch
    Nope is Jordan Peele’s latest chiller featuring Daniel Kaluuya (above) who starred in his earlier film Get Out. Ranch owners spot something in the Californian sky. They will wish it was the cloud it resembles. UK cinemas from 12 August.
    Read
    Methuselah’s Zoo is by animal longevity specialist Steven Austad, who asks what we can learn from long-living animals such as centuries-old sharks and tube worms. It is best to study them in the wild, says Austad. On sale 16 August.

    Visit
    Neofossils are plastics made from biomass that could sequester a … More

  • in

    Explorer review: The amazing story of adventurer Ranulph Fiennes

    An intriguing documentary about the life and adventures of Ranulph Fiennes, one of the last hero-explorers of our time, packs an altogether different punch at the end, discovers Simon Ings

    Humans

    3 August 2022

    By Simon Ings

    Ranulph Fiennes: his expeditions were the last of their kindRoyal Geographical Society/Alamy
    Explorer
    Matthew Dyas
    On release now

    EXPLORER is a documentary about Ranulph Fiennes, who led the first expedition to circumnavigate Earth from pole to pole without recourse to flight.
    Its subject emerges slowly from snatches of past documentaries, interviews, home movies and headlines. The film touts Fiennes’s unknowability: a risky strategy for those new to the man and his achievements, though in time it pays off handsomely for director Matthew Dyas.
    Fiennes isn’t motivated by mysterious and delicate internal forces; this … More

  • in

    A new James Webb telescope image reveals a galactic collision’s aftermath

    It’s not easy being ringed. A newly released image from the James Webb Space Telescope, or JWST, shows the Cartwheel Galaxy still reeling from a run-in with a smaller galaxy 400 million years ago.

    The Cartwheel Galaxy, so called because of its bright inner ring and colorful outer ring, lies about 500 million light-years from Earth. Astronomers think it used to be a large spiral like the Milky Way, until a smaller galaxy smashed through it. In earlier observations with other telescopes, the space between the rings appeared shrouded in dust.

    Now, JWST’s infrared cameras have peered through the dust and found previously unseen stars and structure (SN: 7/11/22). The new image shows sites of intense star formation throughout the galaxy that were triggered by the collision’s aftereffects. Some of those new stars are forming in spokelike patterns between the central ring and the outer ring, a process that is not well understood.

    When the Hubble Space Telescope observed the Cartwheel Galaxy in visible light (left), the spokes between the galaxy’s bright rings were barely visible wisps. JWST’s infrared eyes brought them into vivid focus (right). Near-infrared light (blue, orange and yellow) traces newly forming stars; mid-infrared light (red) highlights the galaxy’s chemistry.Left: Hubble/NASA and ESA; Right: NASA, ESA, CSA, STScI and Webb ERO Production Team

    Ring galaxies are rare, and galaxies with two rings are even more unusual. That strange shape means that the long-ago collision set up multiple waves of gas rippling back and forth in the galaxy left behind. It’s like if you drop a pebble in the bathtub, says JWST project scientist Klaus Pontoppidan of the Space Telescope Science Institute in Baltimore. “First you get this ring, then it hits the walls of your bathtub and reflects back, and you get a more complicated structure.”

    The effect probably means that the Cartwheel Galaxy has a long road to recovery ahead — and astronomers don’t know what it will look like in the end.

    As for the smaller galaxy that caused all this mayhem, it didn’t stick around to get its picture taken. “It’s gone off on its merry way,” Pontoppidan says. More