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Space Earth

Exploding Stars May Have Assaulted Ancient Earth (sciencemag.org) 24

sciencehabit shares a report from Science Magazine: Over the past 2 decades, researchers have found hundreds of radioactive atoms, trapped in seafloor minerals, that came from an ancient supernova explosion marking the death of a nearby star. Erupting from hundreds of light-years away, the flash of x-rays and gamma rays probably did no harm on Earth. But the expanding fireball also accelerated cosmic rays -- mostly nuclei of hydrogen and helium -- to close to the speed of light. These projectiles arrived stealthily, decades later, ramping up into an invisible fusillade that could have lasted for thousands of years and might have affected the atmosphere -- and life. In a flurry of studies and speculation, astronomers have sketched out their potential effects, including a depleted ozone layer, cancer-causing particles, wildfires, and a cooling of the climate that could have helped initiate the ice ages 2.5 million years ago. Most paleontologists are yet to be convinced, but astronomers argue that such supernovae could explain some extinction events that lack customary triggers like volcanic outbursts or asteroid impacts.
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Exploding Stars May Have Assaulted Ancient Earth

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  • When dealing with something like atoms, hundreds is not a big number...

    • When dealing with something like atoms, hundreds is not a big number...

      From reading TFA, they think they're from a supernova explosion in what is now a part of the Scorpius-Centaurus OB Association (Sco OB2), which seemed to be in the perfect spot—300 light-years from Earth—about 2.5 million years ago. How many atoms of iron-60 would you expect to (easily) find here from that radius, so long ago?

      One team also found 181 atoms of plutonium-244, which they believe is a product of collisions between neutron stars—cinders left behind by supernovae. These collis

      • I'm fascinated by their ability to quantify the number of atoms so precisely. AMS technology is really impressive. I found myself more interested in that aspect of the article than the scientific conclusions and speculation.

  • Please (Score:1, Funny)

    by Tablizer ( 95088 )

    My dog died in a supernova explosion, you insensitive clod!

  • What's the statute of limitations on interstellar assault? How many light years before you can't pursue charges?

  • and become a space faring species with colonies hundreds of light years away. A supernova close by could wipe out complex life on earth. This is in addition to the other threats that could harm us, eg: asteroid impact, or things as a result of our own stupidity like climate change and atom bombs.

  • This was a fairly interesting idea when i first heard it.... back in the 70's. Still is; i guess younger people needed reminding.
  • by rickb928 ( 945187 ) on Saturday July 17, 2021 @03:49PM (#61592421) Homepage Journal

    "hundreds of light-years away...."

    "decades later...."

    Math. As if anyone really uses it anymore.

    • by eric777 ( 613330 )
      Reading comprehension - possibly as important as math.

      Allow me to clarify: "These projectiles arrived stealthily, decades [after the arrival of the flash of x-rays and gamma rays] later"

      The word "later" is meant in respect to the arrival time of the x-rays, not the creation time of said x-rays.

Were there fewer fools, knaves would starve. - Anonymous

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