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    On Sonorous Seas review: What a dead whale can tell us

    When a beaked whale carcass washed up near her home, part of a mass stranding around the region, Mhairi Killin was inspired to launch an artistic challenge to the military’s impact in the area

    Humans

    10 August 2022

    By David Stock
    A “constellation” of data points showing where the dead whales washed upMhairi Killin
    On Sonorous Seas
    An exhibition led by Mhairi Killin in collaboration with others
    An Tobar, Isle of Mull, UKCloses 27 August
    SOMETIMES art and science come together to raise our awareness of a compelling issue. One such occasion is a multimedia exhibition called On Sonorous Seas, led by artist Mhairi Killin and prompted by her experience of a mass stranding of dead whales.
    At the An Tobar gallery on the Isle of Mull in the Inner Hebrides, UK, … More

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    Secrets of an ancient Chinese recipe for bronze finally deciphered

    Metal-making practices described in a 2300-year-old text called the Kaogong Ji are more sophisticated than anyone realised

    Humans

    10 August 2022

    By Jason Arunn Murugesu
    A Chinese bronze container from the fifth century BCB Christopher / Alamy
    THE missing ingredients of an ancient Chinese recipe for bronze may have been uncovered, revealing another level of sophistication in the practice of chemistry at the time.
    Kaogong Ji, a 2300-year-old text, is the oldest technical encyclopedia in the world. The book contains instructions on how to make several objects, such as metal drums, chariots and weapons. It also contains six recipes for bronze that have long puzzled researchers.
    While bronze-making wasn’t unique to China at that time, Ruiliang Liu at the British Museum in London says the style and scale of the bronzes produced there was unrivalled.Advertisement
    “We asked ourselves, how can Asian and Chinese people manage to produce so many bronzes [at that time],” says Liu.
    Bronze is typically made by combining copper and tin. The recipe mystery centres on two ingredients called jin and xi that researchers have been unable to identify. In modern Mandarin, jin means gold, but in antiquity it is believed to have referred to copper or a copper alloy. Meanwhile, xi has long been considered to refer to tin.
    But chemical analyses of bronze vessels from that time period suggest that jin and xi can’t simply be copper and tin.
    Liu and his colleagues analysed previously compiled data on the chemical composition of knife-shaped Chinese coins produced in the same era as when the recipes were recorded. By teasing out the relationships between the metals present in the coins, the researchers suggest the objects were created using pre-made alloys.
    They discovered that the higher the lead concentration in the coins, the lower the concentration of both copper and tin. The coins with the highest concentration of copper also had the highest concentration of tin. These findings suggest that lead was being mixed into an alloy of copper and tin – a bronze alloy.
    By modelling different combinations, the team determined that an 80:15:5 copper-tin-lead alloy mixed with a 50:50 copper-lead alloy in various ratios was the best match with the chemical coin data.
    These pre-made alloys are likely to be jin and xi respectively as recorded in the Kaogong Ji, says Liu. But he adds that the recipes in the book may not reflect how bronze was usually made.
    “If anything, the recipes are too specific,” he says. “The people who actually got their hands dirty probably couldn’t read or write so they wouldn’t have been able to record the recipe. I think there is a gap in knowledge between the person who wrote the recipe and the person who did the real work.”
    Jianjun Mei at the University of Cambridge isn’t totally convinced by the findings. He says these recipes shouldn’t considered accurate records of practices used at the time. “These officials [who wrote the text] might only pay attention to the most important materials, such as copper and tin, rather than all other materials,” he says. The recipes still largely work if you take jin and xi to be copper and tin, he says.
    Bronze was used in ancient China to make large vessels for religious purposes, says Jessica Rawson at the University of Oxford. “In China, they had a huge workforce and so could afford to use a very complicated system with a lot more metal than in the West,” she says.
    Journal reference: Antiquity, DOI: 10.15184/aqy.2022.81).

    More on these topics: More

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    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.

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    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

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    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

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    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

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    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

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    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

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    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