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    Here’s the best timeline yet for the Milky Way’s big events

    A new analysis of nearly a quarter million stars puts firm ages on the most momentous pages from our galaxy’s life story.

    Far grander than most of its neighbors, the Milky Way arose long ago, as lesser galaxies smashed together. Its thick disk — a pancake-shaped population of old stars — originated remarkably soon after the Big Bang and well before most of the stellar halo that envelops the galaxy’s disk, astronomers report March 23 in Nature.

    “We are now able to provide a very clear timeline of what happened in the earliest time of our Milky Way,” says astronomer Maosheng Xiang.

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    He and Hans-Walter Rix, both at the Max Planck Institute for Astronomy in Heidelberg, Germany, studied almost 250,000 subgiants — stars that are growing larger and cooler after using up the hydrogen fuel at their centers. The temperatures and luminosities of these stars reveal their ages, letting the researchers track how different epochs in galactic history spawned stars with different chemical compositions and orbits around the Milky Way’s center.

    “There’s just an incredible amount of information here,” says Rosemary Wyse, an astrophysicist at Johns Hopkins University who was not involved with the study. “We really want to understand how our galaxy came to be the way it is,” she says. “When were the chemical elements of which we are made created?”

    Xiang and Rix discovered that the Milky Way’s thick disk got its start about 13 billion years ago. That’s just 800 million years after the universe’s birth. The thick disk, which measures 6,000 light-years from top to bottom in the sun’s vicinity, kept forming stars for a long time, until about 8 billion years ago.

    During this period, the thick disk’s iron content shot up 30-fold as exploding stars enriched its star-forming gas, the team found. At the dawn of the thick disk era, a newborn star had only a tenth as much iron, relative to hydrogen, as the sun; by the end, 5 billion years later, a thick disk star was three times richer in iron than the sun.

    Xiang and Rix also found a tight relation between a thick disk star’s age and iron content. This means gas was thoroughly mixed throughout the thick disk: As time went on, newborn stars inherited steadily higher amounts of iron, no matter whether the stars formed close to or far from the galactic center.

    But that’s not all that was happening. As other researchers reported in 2018, another galaxy once hit our own, giving the Milky Way most of the stars in its halo, which engulfs the disk (SN: 11/1/18). Halo stars have little iron.

    The new work revises the date of this great galactic encounter: “We found that the merger happened 11 billion years ago,” Xiang says, a billion years earlier than thought. As the intruder’s gas crashed into the Milky Way’s gas, it triggered the creation of so many new stars that our galaxy’s star formation rate reached a record high 11 billion years ago.

    The merger also splashed some thick disk stars up into the halo, which Xiang and Rix identified from the stars’ higher iron abundances. These “splash” stars, the researchers found, are at least 11 billion years old, confirming the date of the merger.

    The thick disk ran out of gas 8 billion years ago and stopped making stars. Fresh gas around the Milky Way then settled into a thinner disk, which has given birth to stars ever since — including the 4.6-billion-year-old sun and most of its stellar neighbors. The thin disk is about 2,000 light-years thick in our part of the galaxy.

    “The Milky Way has been quite quiet for the last 8 billion years,” Xiang says, experiencing no further encounters with big galaxies. That makes it different from most of its peers.

    If the thick disk really existed 13 billion years ago, Xiang says, then the new James Webb Space Telescope (SN: 1/24/22) may discern similar disks in galaxies 13 billion light-years from Earth — portraits of the Milky Way as a young galaxy. More

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    How language evolved: A new idea suggests it’s all just a game

    Our mastery of language presents many mysteries, not least where grammar comes from and how children learn to speak so effortlessly. Now researchers argue that it all makes sense if you think of language as a game of charades

    Humans

    23 March 2022

    By Morten H. Christiansen and Nick Chater
    Harriet noble
    IN THE early afternoon of 16 January 1769, HMS Endeavour dropped anchor in the Bay of Good Success on Tierra del Fuego. When Captain James Cook and his crew came ashore, they were met by a group of Indigenous people, probably Haush hunter-gatherers. Two of Cook’s party advanced. Soon, two of the Haush also stepped forward, displayed small sticks and threw them aside. Cook’s men interpreted this as an indication of peaceful intentions. They were right: the groups were soon exchanging gifts and sharing food. With no common language and inhabiting utterly different worlds, they could nonetheless communicate through a high-stakes game of cross-cultural charades.
    Most of us have faced our own communication challenges, perhaps resorting to pointing and gesturing when abroad. And yet in daily life, we rarely give language a second thought – never mind its many perplexing mysteries. How can noises convey meaning? Where do the complex layers of linguistic patterns come from? How come children learn language so easily, whereas chimpanzees can scarcely learn it at all?
    We believe these questions have remained unanswered because scientists have been looking at language all wrong. A growing body of research undermines prevailing ideas that humans possess an innate language ability somehow wired into our brains, encoding grammatical rules. In our new book, The Language Game, we argue that language isn’t about rules at all. As Cook’s encounter illustrates, it is about improvisation, freedom and the desire to be understood, constrained only by our imaginations. This radical idea helps to explain those long-standing mysteries about language – as well as how language evolved and why it makes humans special.
    For … More

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    Levitating plastic beads mimic the physics of spinning asteroids

    Some asteroids can barely hold it together.

    Rather than solid lumps of rock, ‘rubble pile’ asteroids are loose collections of material, which can split apart as they rotate (SN: 3/16/20). To understand the inner workings of such asteroids, one team of scientists turned to levitating plastic beads. The beads clump together, forming collections that can spin and break up, physicist Melody Lim of the University of Chicago reported March 15 at a meeting of the American Physical Society in Chicago.

    It’s an elegant dance that mimics the physics of asteroid formation, which happens too slowly to observe in real-life space rocks. “These ‘tabletop asteroids’ compress phenomena that take place over kilometers [and] over hundreds of thousands of years to just centimeters and seconds in the lab,” Lim said. The results are also reported in a paper accepted in Physical Review X.

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    Lim and colleagues used sound waves to levitate the plastic beads, which arranged themselves into two-dimensional clumps. Acoustic forces attract the beads to one another, mimicking the gravitational attraction between bits of debris in space. Separate clumps then coalesced similarly to how asteroids are thought to glom onto one another to grow.

    [embedded content]
    Levitated by sound waves, plastic beads, which are about 150 micrometers across, clump together into a loosely bound 2-D conglomeration (shown at 1/50th the original speed). When spun too fast, one such structure deforms then splits apart (shown at 1/70th the original speed).

    When the experimenters gave the structures a spin using the sound waves, the clumps changed shape above a certain speed, becoming elongated. That could help scientists understand why ‘rubble pile’ asteroids, can have odd structures, such as the ‘spinning tops’ formed by asteroids Bennu and Ryugu (SN: 12/18/18).

    Eventually, the fast-spinning clumps broke apart. This observation could help explain why asteroids are typically seen to spin up to a certain rate, but not beyond: Speed demons get split up. More

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    NASA’s exoplanet count surges past 5,000

    It’s official: The number of planets known beyond our solar system has just passed 5,000.

    The exoplanet census surpassed this milestone with a recent batch of 60 confirmed exoplanets. These additional worlds were found in data from NASA’s now-defunct K2 mission, the “second life” of the prolific Kepler space telescope, and confirmed with new observations, researchers report March 4 at arXiv.org.

    As of March 21, these finds put NASA’s official tally of exoplanets at 5,005.

    It’s been 30 years since scientists discovered the first planets orbiting another star — an unlikely pair of small worlds huddled around a pulsar (SN: 1/11/92). Today, exoplanets are so common that astronomers expect most stars host at least one (SN: 1/11/12), says astronomer Aurora Kesseli of Caltech.

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    “One of the most exciting things that I think has happened in the last 30 years is that we’ve really started to be able to fill out the diversity of exoplanets,” Kesseli says

    Some look like Jupiter, some look — perhaps — like Earth and some look like nothing familiar. The 5,005 confirmed exoplanets include nearly 1,500 giant gassy planets, roughly 200 that are small and rocky and almost 1,600 “super-Earths,” which are larger than our solar system’s rocky planets and smaller than Neptune (SN: 8/11/15).

    Astronomers can’t say much about those worlds beyond diameters, masses and densities. But several projects, like the James Webb Space Telescope, are working on that, Kesseli says (SN: 1/24/22). “Not only are we going to find tons and tons more exoplanets, but we’re also going to start to be able to actually characterize the planets,” she says.

    And the search is far from over. NASA’s newest exoplanet hunter, the TESS mission, has confirmed more than 200 planets, with thousands more yet to verify, Kesseli says (SN: 12/2/21). Ongoing searches from ground-based telescopes keep adding to the count as well.

    “There’s tons of exoplanets out there,” Kesseli says, “and even more waiting to be discovered.” More

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    Radioactive gummy bears, renewable trams and moon geese

    Josie Ford
    Hybrid learning
    A man in a hide jerkin and disposable face mask sits knapping flints against the backdrop of an unaccountably large, bright red tractor. Rounding a corner, a 3-metre-high luminous yellow grinning gummy bear suddenly looms over us, from which we flee through a door into a side room where Greater Manchester mayor Andy Burnham is talking soulfully about 100 per cent renewable trams.
    Not Feedback’s latest cheese dream – although close – but sure signs we were on the shop floor at New Scientist Live Manchester, as part of our drive to bring the office stationery cupboard to you.
    Like many people, Feedback currently finds being in real places with real people a discombobulating experience that requires several deep-breathing exercises and us remembering to wear something on our bottom half. Many attendees in Manchester weren’t actually in Manchester, but watching it all from the safety of their own underpants at home, which brings its own challenges, it turns out. When digital attendees complain that the main stage is freezing, getting someone to turn up the thermostat in the hall doesn’t cut it. Lesson learned as the boundaries between the virtual and physical worlds slowly melt, as indeed the people in the hall did.Advertisement
    The truth is out there
    “Don’t think of a black hole as a Hoover, think of it as a couch cushion”. Astrophysicist Becky Smethurst – Dr Becky to her legion of YouTube fans – won the prize for the most unexpected metaphor of the event, her point being that you are less likely to get sucked into a black hole than to lose your car keys down the side of one. Or something like that.
    Meanwhile, we were delighted to learn from Dallas Campbell and Suzie Imber’s talk on how to leave Earth about the 1638 book The Man in the Moone, written by Church of English bishop Francis Godwin, in which the protagonist flies to the moon in a chariot towed by moon geese. We would take this option, which strikes us as classier than the unspeakably vulgar rockets favoured by today’s billionaire class.
    We also now know the current location of the first sandwich in space, what an industrial vacuum does to a marshmallow and how to make a rocket with half an Alka-Seltzer and a 35-millimetre film canister. That’s definitely one not to try at home. For anyone tempted, all the talks are available in the metaverse.
    Going nuclear
    The 3-metre-high mutant gummy bear was, it turns out, advertising the benefits of nuclear power. Feedback regards this as brave, as we also do the UK Atomic Energy Authority titling a talk “Nuclear Fusion: Forever 30 years away”.
    Still, we learn that a gummy bear is about the same size as a uranium fuel pellet, that one fuel pellet produces enough power to drive an electric car 20,000 miles and so a 3-metre-high gummy bear would make enough electricity to power 2 million electric cars for a year in the UK. This makes us happy.
    Blowing in the wind
    Meanwhile, out in the real world, the real world was still going on. The gummy bear is possibly a more appropriate unit of power for a family magazine than that contained in a tweet from the Victorian Trades Hall Council that Paul Campbell forwards us following our session on “how big is a gigawatt?” in last week’s Feedback.
    It celebrates the announcement of 2 gigawatts of wind power capacity to be installed off the Australian state’s coast in the coming 10 years, or as the tweet has it in an accompanying picture: “SH**LOADS OF POWER. SH**LOADS OF JOBS”.
    Clue: it wasn’t “shed”. We idly wonder if this is now a unit of power and how many horses it would take to produce it. Around 2.7 million, we make it. They would be a truly magnificent sight riding in the waves, although we do wonder whether any of this counts as clean energy.
    Butt out
    While our back was turned, we also discover that a portion of Twitter declared 1 to 8 March InverteButt Week in celebration of the backsides of creatures without backbones.
    We doubt the world truly needed this, but then again, with past headlines in this august publication such as “Comb jelly videos are rewriting the history of your anus”, perhaps people in glass houses shouldn’t throw… slugs.
    This leads us to delve rather more deeply than we might otherwise have done into the lifestyle and morphology of the bristle worm Ramisyllis multicaudata, a detailed study of which, published last year, seems to have been a prime mover of InverteButt Week. The worm lives, with delightful specificity, within sponges in Darwin Harbour, northern Australia. Its single head is buried deep within the sponge, but its body randomly branches out into up to 1000 rear ends that poke hopefully out of it. The gut is continuous throughout all these branches, yet doesn’t seem to process any food, leading to speculation that the worm has “adopted a fungal lifestyle”.
    This sounds pleasingly louche, like flying with the moon geese. Even more fun is that, when it comes to reproduction, new heads – complete with brains and eyes – start forming and bud off from the worm’s butts. Cute.
    Got a story for Feedback?Send it to feedback@newscientist.com or New Scientist, Northcliffe House, 2 Derry Street, London W8 5TTConsideration of items sent in the post will be delayed
    You can send stories to Feedback by email at feedback@newscientist.com. Please include your home address. This week’s and past Feedbacks can be seen on our website. More

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    The internet is a key battleground for truth about the Ukraine war

    The threats of cyberwarfare and online disinformation loom over Russia’s invasion of Ukraine, but even in this online age, war is still life or death for those in the firing line

    Humans

    | Leader

    16 March 2022

    Sean Gallup/Getty Images
    THE ever-growing threats of cyberwarfare and online disinformation are now in the spotlight amid Russia’s invasion of Ukraine. With the NATO military alliance reluctant to establish a no-fly zone over Ukraine, or engage in any other actions that could ignite a much wider conflict, the internet has inevitably become a key battleground.
    But that isn’t to say there haven’t been surprises. On page 8, one expert expresses shock at the volume of online fake news about the war. Clearly, the invasion isn’t the first war associated with this issue – researchers and think tanks have also monitored online propaganda in other recent conflicts, including in Syria and Libya – but it is … More

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    How to perform the culinary technique of spherification at home

    By Sam Wong
    Zhanna Tretiakova/Alamy
    IF YOU eat at fancy places, you may have encountered orbs of sauce or puree, held inside a membrane, that burst in your mouth. Making them involves a little chemistry, but it can be done at home.
    Now a staple of modernist cuisine, the spherification technique was patented in 1942 by food scientist William Peschardt and later popularised by chef Ferran Adrià at El Bulli restaurant in north-east Spain in the 2000s.
    To try it, you need two special ingredients that can be ordered online. One is a salt called sodium alginate, which comes from brown algae. Alginate is formed … More

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    Don't miss: The chance to get life lessons from plants and fungi

    Read
    Don’t Trust Your Gut says data scientist Seth Stephens-Davidowitz. You probably know less than you think about how to be healthy and happy. So, it may be time to ignore your instincts and try self-help by data. Out on 9 June.
    Ingela Ihrman
    Visit
    Rooted Beings can teach us a lot about how to connect with each other, according to this exhibition on plants and fungi. Work from the botanical archives will be shown alongside new art at London’s Wellcome Collection from 24 March.Advertisement

    Read
    The Flight of the Aphrodite is a thrilling new sci-fiction novel from S. J. Morden about an eventful mission to Jupiter’s moons. Ship and crew are already at breaking point and then it seems they have uninvited company.

    More on these topics: More