Could Asteroids Bombard the Earth to Cause a Mass Extinction in 10 Million Years?

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Source:  By Sanna Alwmark, Matthias Meier, Scientific American


Excerpt: Given the evidence that an asteroid triggered the dinosaur extinction, it makes sense to ask whether showers of asteroids could be to blame for regular extinction events....

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Early universe’s ‘little red dots’ may be black hole stars

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By Daniel Clery , Science.  Excerpt: It’s as if the baby universe had caught a case of measles. Since NASA’s JWST observatory began peering into the distant universe in 2022, it has discovered a rash of “little red dots”—hundreds of them, shining within the first billion years of the 13.8-billion-year-old universe, so small and red that they defied conventional explanation. Only in the past few months has a picture begun to emerge. The little red dots, astronomers say, may be an entirely new type of object: a colossal ball of bright, hot gas, larger than the Solar System, powered not by nuclear fusion, but by a black hole. ...JWST couldn’t resolve the dots into a recognizable shape, which meant they must have been tiny—less than 2% of the diameter of the Milky Way....  Full article at https://www.science.org/content/article/early-universe-s-little-red-dots-may-be-black-hole-stars . 
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Planet-Eating Stars Hint at Earth’s Ultimate Fate

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By Matthew R. Francis , Eos/AGU.  Excerpt: Our Sun is about halfway through its life, which means Earth is as well. After a star exhausts its hydrogen nuclear fuel, its diameter expands more than a hundredfold, engulfing any unlucky planets in close orbits. That day is at least 5 billion years off for our solar system, but scientists have spotted a possible preview of our world’s fate. Using data from the  TESS (Transiting Exoplanet Survey Satellite) observatory , astronomers  Edward Bryant  of the University of Warwick and  Vincent Van Eylen  of University College London compared systems with stars in the main sequence of their lifetimes—fusing hydrogen, like the Sun—with post–main sequence stars closer to the end of their lifetimes, both with and without planets. “We saw that these planets are getting rarer [as stars age],” Bryant said. In other words,  planets are disappearing as their host stars grow old . The comparison between planetary systems w...
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Titan might not have an ocean after all

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By Hannah Richter , Science.  Excerpt: In the late 2000s, planetary scientists scoured data gathered by NASA’s Cassini mission, a Saturn orbiter, about the planet’s mysterious icy moon Titan. Their exciting conclusion: The frozen world harbored an ocean sloshing around tens of kilometers beneath a thick ice shell. The ocean, hundreds of kilometers deep itself, might even be a cauldron for the “prebiotic” organic chemistry that led to life on Earth, they proposed. Now, nearly 2 decades later, researchers think they may have gotten the story all wrong. Research  presented today  here at the American Geophysical Union’s annual meeting and  published in  Nature  claims that although Titan may have once harbored a liquid ocean, today it is frozen, except for smaller melted zones deep beneath the surface. If true, the discovery will upend the long-standing assumption that Saturn’s biggest moon is a water world, like other moons in the outer Solar System,  in...
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