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    A NASA rover finally found Mars’ missing carbon

    The carbon that once warmed Mars’ atmosphere has been locked in its rusty rocks for millennia. 

    That’s the story revealed by a hidden cache of carbon-bearing minerals unearthed by NASA’s Curiosity rover along its route up a Martian mountain. The finding is the first evidence of a carbon cycle on the Red Planet, but also suggests that Mars lost its life-friendly climate because that carbon cycle was slow, researchers report in the April 18 Science. More

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    Yes, there really is a black hole on the loose in Sagittarius

    For the first time, astronomers have confirmed the existence of a lone black hole — one with no star orbiting it.

    It’s “the only one so far,” says Kailash Sahu, an astronomer at the Space Telescope Science Institute in Baltimore.

    In 2022, Sahu and his colleagues discovered the dark object coursing through the constellation Sagittarius. A second team disputed the claim, saying the body might instead be a neutron star. New observations from the Hubble Space Telescope now confirm that the object’s mass is so large that it must be a black hole, Sahu’s team reports in the April 20 Astrophysical Journal. More

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    Check out some of the weird rocks that have turned up on Mars

    As the Mars rover Perseverance crested the top of Witch Hazel Hill, its operators back on Earth expected amazing things. This area on the western rim of the Jezero crater, along an ancient river delta that Perseverance has been exploring since it landed in 2021, is thought to contain some of the oldest rocks on the planet’s surface. The light-toned, layered materials promise a record of a wetter time, possibly one that hosted life.

    The team did not expect what they found on March 11: a dark rock resembling a clutch of frog’s eggs. Dubbed St. Paul’s Bay, the rock looks nothing like its neighbors. Where it came from and how it formed are a mystery. More

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    A nebula’s X-ray glow may come from a destroyed giant planet

    The decades-long mystery of a never-ending explosion of X-rays around the remains of a dead star may have finally been solved. The radiation probably originates from the scorching-hot wreckage left behind by a giant planet’s annihilation.

    This discovery stems from four decades of X-ray observations of the Helix Nebula, located 650 light-years from Earth. The stream of X-ray radiation remained effectively constant over at least 20 years, researchers report in the January Monthly Notices of the Royal Astronomical Society. The best explanation, the scientists say, is that the ruins of a Jupiter-sized world continuously fall onto the nebula’s white dwarf star, getting frazzled and glowing in X-rays. More

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    JWST spots the earliest sign yet of a distant galaxy reshaping its cosmic environs

    The James Webb Space Telescope has caught a distant galaxy blowing an unexpected bubble in the gas around it, just 330 million years after the Big Bang.

    The galaxy, dubbed JADES-GS-z13-1, marks the earliest sign yet spotted of the era of cosmic reionization, a transformative period in the universe’s history when the first stars and galaxies began to reshape their environment, astronomers report in the March 27 Nature.

    “It definitely puts a pin in the map of the first point where [reionization] very likely has already started,” says astrophysicist Joris Witstok at the University of Copenhagen. “No one had predicted that it would be this early” in the universe’s history. More

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    A map of 14 million galaxies and quasars deepens a dark energy mystery

    ANAHEIM, Calif. — Change is in the air. New data strengthen a hint that dark energy, long thought to be constant force in the universe, might change over time.Dark energy explains the observation that the universe’s expansion rate is accelerating. But its origins are unknown. It’s typically expected to have constant density across the billions of years of the universe’s history. So when researchers from the Dark Energy Spectroscopic Instrument, or DESI, reported in 2024 that dark energy might vary over time based on their first year of data, it shook cosmology to its core.

    Many scientists expected that the standard picture would prevail with additional data from DESI. But that hasn’t happened. Instead, with three years of DESI data, the preference for a changing, or dynamical dark energy has grown. More

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    The nearest single star to Earth has four small planets

    The nearest single star to the sun, Barnard’s star, has a brood of planets all its own. The red dwarf star, about six light-years from Earth, hosts four close-in planets each about two to three times the mass of Mars, astronomers report in the March 20 Astrophysical Journal Letters.

    “Barnard’s star has a long history of claimed detections, but none of them could be confirmed for a long time,” says astronomer Ritvik Basant of the University of Chicago. “It’s pretty exciting to know what’s orbiting the nearest stars.” More

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    New baby pictures of the universe deepen a cosmic mystery

    The clearest pictures yet of the newborn cosmos strengthen the prevailing model of the universe but deepen a mystery about its expansion rate.

    Measurements of this rate, known as the Hubble constant, have produced conflicting results. Cosmologists hoped that new data from the Atacama Cosmology Telescope in Chile, which examines the oldest light in the universe, would clear things up and possibly reveal physics that diverges from the standard model of cosmology. But those results, announced March 18 in a webinar, only affirmed that model. More