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Supernova Left Its Mark In Ancient Bacteria

Posted by samzenpus on from the don't-look-directly-at-the-supernova dept.

ananyo writes "Sediment in a deep-sea core may hold radioactive iron spewed by a distant supernova 2.2 million years ago and preserved in the fossilized remains of iron-loving bacteria. If confirmed, the iron traces would be the first biological signature of a specific exploding star. Scientists have found the isotope iron-60, which does not form on Earth, in a sediment core from the eastern equatorial Pacific Ocean, dating to between about 1.7 million and 3.3 million years ago. The iron-60, which appears in layers dated to around 2.2 million years ago, could be the remains of magnetite chains formed by bacteria on the sea floor as radioactive supernova debris showered on them from the atmosphere, after crossing inter-stellar space at nearly the speed of light."

5 of 37 comments (clear)

  1. I'm not saying it's aliens, but... by DougOtto · · Score: 3, Funny

    it's aliens.

    --
    Solving Unix problems since 1989...
  2. One supernova of many in Local Bubble by Morgaine · · Score: 5, Informative

    Our solar system resides in an area of our galaxy called the "Local Bubble", roughly a few hundred lightyears across. This region is very empty compared to the average interstellar medium in the galaxy, as a result of a large number of supernovae that blew out a sort of cavity in our interstellar neck of the woods long ago. In actual structure it's more of an irregular "Local Chimney" going right through the galactic disc rather than a spherical bubble.

    As a result, pinning the cause of TFA's observations to a single supernova is not all that simple, as supernovae were very common in the Sun's general neighborhood in our galactic past..

    Here's a nice graphic of the larger features in and around our local bubble. It's a fascinating subject if you enjoy understanding our location in a galactic context.

    --
    "The question of whether machines can think is no more interesting than [] whether submarines can swim" - Dijkstra
    1. Re:One supernova of many in Local Bubble by argStyopa · · Score: 4, Interesting

      It's one of the few (to me) persuasive arguments that life might be quite rare, in that so many other ways our sun and system is apparently entirely pedestrian.

      Our seemingly interesting local neighborhood and circumstances for only the last 5-10 million years might mean that intelligent life - on this planet at least - might be existing only in what (on a galactic scale) amounts to a spark floating for a moment in the flickering gap between tongues of a campfire's flame.

      It's humbling, really.

      --
      -Styopa
    2. Re:One supernova of many in Local Bubble by smpoole7 · · Score: 3, Interesting

      > life might be quite rare ...
      and ...
      > life is much more resilient ...

      I'm going to split the difference between you two. I just finished reading John Gribbin's "Alone In The Universe: Why Our Planet Is Unique." Yes, it's another rehash of the "Rare Earth" hypothesis, but he bases it on some of the latest computer simulations.

      Gribbin says that *simple single-celled life* might be very common throughout our Galaxy. But Gribbin makes the argument that *sentient* life is probably quite rare.

      You may not agree with his conclusion, but he presents the latest evidence and theories for solar system formation. Well worth the read.

      --
      Cogito, igitur comedam pizza.
  3. Suprnova is gone by Spy+Handler · · Score: 3, Funny

    but piratebay and isohunt are still here