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    These scientific feats set new records in 2024

    2024 was studded with record-setting scientific discoveries. From tracing the origins of glow-in-the-dark animals to developing the world’s fastest microscope, these superlative feats captured our imagination.

    Ancient Airburst

    Some 2.5 million years ago, an asteroid combusted in Earth’s atmosphere before it could hit the ground and leave a crater, making the event the oldest known midair explosion. That conclusion is based on a chemical analysis of nearly 120 microscopic rocks buried deep underneath Antarctic ice. The ancient pebbles are rich in olivine and spinel minerals, which suggests the specimens are the asteroid’s remnants, scientists say.

    Chemical analysis of microscopic bits of rock collected in Antarctica (three shown) suggests they are consistent with a type of asteroid known as an ordinary chondrite that broke up in the atmosphere.  Courtesy of Matthias van Ginneken

    The dawn of photosynthesis

    Microfossils in Australia harbor the oldest evidence of photosynthesis. Fossilized bacteria dating to about 1.75 billion years ago preserve structures that resemble thylakoid membranes, which help modern cyanobacteria convert sunlight into oxygen. Scientists had previously suspected that cyanobacteria were photosynthesizing way back then, but the new finding is the first direct evidence.

    Researchers found microscopic fossils of cyanobacteria dubbed Navifusa majensis (left) in 1.73 billion- to 1.78 billion-year-old shale from Australia). A peek inside the fossils revealed black horizontal lines indicating the bacterium contained stacks of membranes known as thylakoids (right) like those in modern bacteria and plants where oxygen-producing photosynthesis takes place.C.F. Demoulin, et al./Nature 2024

    Fastest backflip

    Dicyrtomina minuta springtails can launch themselves up to 60 millimeters in the air and spin at a rate of up to 368 times per second, making the arthropods the fastest known backflippers (SN: 10/5/24, p. 4). An appendage on the underbelly helps the miniature gymnasts lift off while another helps them stick the landing.

    Backflipping arthropods called globular springtails can vault themselves up to 60 millimeters high and spin up to 29 times in the blink of an eye. Two springtails jump off a platform in a lab in this high-speed camera footage.A. Smith

    Wee-est frog

    At just 6.5 millimeters long, a Brazilian flea toad (Brachycephalus pulex) has been crowned the world’s smallest known frog (SN: 3/23/24, p. 4). Petite enough to sit on a pinkie fingernail, the amphibian beat the previous champion by about a millimeter.

    The Brazilian flea toad has nabbed the title of world’s smallest known amphibian and smallest known vertebrate. At just 7 millimeters long on average, the frogs are a fraction the size of a 27-millimeter-wide $1 Brazilian real coin.W.H. Bolaños, I.R. Dias and M. Solé/Zoologica Scripta 2024

    Large genome, small package

    The largest known genetic instruction manual belongs to a tiny fern (SN: 6/29/24, p. 4). Tmesipteris oblanceolata is 15 centimeters long but possesses a genome that is 50 times as large as humans’. If unraveled, the fern’s spool of DNA would stretch 100 meters long, scientists say.

    The yellow balls on this New Caledonian fork fern are synangia, the spore-producing structures in this group of ferns. Oriane Hidalgo

    Oldest bioluminescence

    Bioluminescence has a new birthday. Ancestors of a group of deep-sea corals glowed in the dark 540 million years ago, scientists say. Scientists had thought that animal bioluminescence began about 267 million years ago in an ancestor of sea fireflies — tiny, seed-shaped crustaceans.

    Colonial false gold coral (Savalia) demonstrates its bioluminescence on a Bahamian reef. This form of bioluminescence in octocorals is the oldest yet dated.Sönke Johnsen

    Supersmall knot

    Knots come in all shapes and sizes. Small figure-eight knots hold people as they scale cliffs. Bigger bowlines secure ships to shore. This year, scientists designed the smallest and tightest knot yet (SN: 2/24/24, p. 4). This trefoil knot is made from a string of 54 gold, phosphorus, oxygen and carbon atoms that is pretzeled over itself three times.

    In this simplified illustration of the smallest known molecular knot, a chain of 54 gold (red), phosphorus (purple), oxygen (mauve) and carbon (black) atoms crosses itself three times to form a pretzel-like shape.Z. Li et al/Nature Communications 2024 More

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    A new microbead proves effective as a plastic-free skin scrubber

    A new degradable microbead could soon replace plastic exfoliants in skin cleansers.

    The polymer spheres effectively remove permanent marker and eyeliner on animal skin samples and break down into molecules similar to sugars and amino acids, researchers report December 6 in Nature Chemical Engineering. The beads offer a more environmentally friendly alternative to microplastic beads, the scientists say.

    In 2015, the United States banned companies from adding plastic microbeads to personal care products that get rinsed down the drain to prevent them from entering waterways where marine life might ingest them. Several countries have implemented similar bans, but others still allow companies to add plastic microbeads as scrubbers and exfoliants. More

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    Generative AI is an energy hog. Is the tech worth the environmental cost?

    It might seem like magic. Type a request into ChatGPT, click a button and — presto! — here’s a five-paragraph analysis of Shakespeare’s Hamlet and, as an added bonus, it’s written in iambic pentameter. Or tell DALL-E about the chimeric animal from your dream, and out comes an image of a gecko-wolf-starfish hybrid. If you’re feeling down, call up the digital “ghost” of your deceased grandmother and receive some comfort (SN: 6/15/24, p. 10).

    Despite how it may appear, none of this materializes out of thin air. Every interaction with a chatbot or other generative AI system funnels through wires and cables to a data center — a warehouse full of server stacks that pass these prompts through the billions (and potentially trillions) of parameters that dictate how a generative model responds. More

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    Climate change made 2024 the hottest year on record. The heat was deadly

    Over and over, the numbers tell the same story: 2024 was Earth’s hottest year on record, knocking the previous record holder — 2023 — out of the top spot (SN: 12/6/23). But temperatures alone can’t describe the human cost: humidity that challenges the body’s ability to cool itself; nighttime temps that rob people of sleep; power outages; wildfire smoke; ruined crops; rising cases of mosquito-borne disease (SN: 9/20/24).

    Meanwhile, record-breaking water temperatures in the Atlantic Ocean and the Gulf of Mexico fueled hurricanes Helene and Milton (SN: 10/9/24). Helene’s torrential rains caused flooding across six states in the U.S. Southeast, killing over 200 people (SN: 10/1/24). More

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    Meet a scientist tracking cactus poaching in the Atacama Desert

    Pablo Guerrero has been visiting cacti in the Atacama Desert his whole life, first on family trips to the Chilean coast and later as a researcher studying the impacts of climate change and illegal poaching on the fragile flora.

    The desert, which is the driest spot on Earth beyond the planet’s poles, can be so desolate that NASA uses it to test Mars rovers. But from a young age, Guerrero learned to spot pockets of life hidden within the arid landscape. More

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    Climate stress may undermine male spiders’ romantic gift giving

    Courtship dazzle in spiders can lose some zing in uncertain climates. Males in places with hard-to-predict rain and temperatures devolve into suitors who woo mostly with cheap, useless gifts.

    Researchers have described gift giving in courtship in only 15 or 20 of the world’s more than 50,000 known species of spiders, says evolutionary biologist Maria José Albo of Universidad La República in Montevideo, Uruguay (SN: 7/26/16). Since 2015, she and her lab have focused on spiders that flirt mostly in evenings and nights among the rocks and pebbles of rivers of Uruguay and southern Brazil. More

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    New videos reveal the hidden lives of Andean bears

    Camera collar footage is unveiling the secret lives of Andean bears (Tremarctos ornatus), South America’s only surviving ursid. A wild Andean bear in Peru was caught eating soil or clay, courting females and even cannibalizing a dead bear cub.

    “It’s so hard to see an Andean bear,” says Ruthmery Pillco Huarcaya, a wildlife biologist at Amazon Conservation, a nongovernmental organization in Cusco, Peru. Scientists estimate there are fewer than 20,000 left in the wild. “And it’s even harder to see what they are doing.” Even though the bears are deep brown or black with bright spectacled faces and can weigh up to 340 pounds, they’re tricky to spot in the dense, steep forests of the Andes. More

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    Starchy nanofibers shatter the record for world’s thinnest pasta

    The world record for the thinnest pasta has been shattered, though the new, narrow noodles are better suited to wound dressings than the dinner table.

    From white flour, researchers made starch-rich nanofibers that are about 370 nanometers thick, on average — or about two hundredths the thickness of a human hair. The nano-noodles could be used in biodegradable bandages, chemist Adam Clancy and colleagues reported October 30 in Nanoscale Advances.

    To make the noodle “dough,” the scientists mixed the flour with formic acid, a liquid that helps uncoil the long starch molecules in the flour. “Normally, if you want to cook starch, then you use water and heat to break up the tight packing of starch,” says Clancy, of University College London. “We do that chemically with formic acid. So we effectively pickle it instead of cooking it.” More