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Supernova evidence found in terrestrial bacteria

 

Not long ago, a rare form of iron was found in oceanic crust worldwide dating to about 3.5 million years ago. Astronomers at the time noted that would be consistent with a relatively nearby supernova explosion. Now, another groups of scientists have the same substances incorporated into bacteria dating to the same time:

Columbus Dispatch — Dust from supernovae contains a radioactive isotope of iron called Fe-60, which could settle on Earth and be taken up by certain types of bacteria called magnetotactic. These single-cell organisms take up small bits of iron, producing nanometer-size grains of an iron-oxygen compound called magnetite, which they presumably use for navigation.The recent news from the American Physical Society meeting is that Fe-60 was detected in these bacterial fossils using clever technology developed for particle accelerators. Fe-60 does not occur naturally on Earth and is produced almost exclusively in supernova explosions.

These measured amounts of Fe-60 are small, but they are well within the detection limits of modern technology. In fact, two previous measurements by a different group using the same accelerator technology found Fe-60 in other ocean-floor sediments of about the same age — about 2.5 million years ago. The newly reported results are different in that the Fe-60 is now linked to fossils of magnetotactic bacteria.

And what is the most likely candidate for that supernova? The Scorpius–Centaurus Association, which our system drifted by beginning about three millions years ago and which includes, among other massive stars, the mighty Antares. Better known as the ruby red heart of Scorpio.

Comments

  1. StevoR : Free West Papua, free Tibet, let the Chagossians return! says

    Thinking of which, it’d be oddly symetrically apt if Antares – a supernova candidate itself -were to go supernova tonight then – and it’d be well placed in the sky right now too.

    Although, I’f miss it.

  2. docsarvis says

    Cool information, Steven. Thanks for posting. This is the type of stuff that makes science interesting, and is useful when people ask why we should spend money on this type of research.

  3. StevoR : Free West Papua, free Tibet, let the Chagossians return! says

    No worries. Really is my pleasure -love this kinda stuff.

    Desperately hope to see a supernova in my lifetime but if I could order one up it’d be Eta Carinae on a clear night!

    (Sorry northern hemisphere. Yeah, I missed SN1987 A at the time. Yeah I knoew its kinda greedy. One near the equator that all of us could see would be great too if it left the familiar constellations pretty much as they are too! I.e. I’d miss Betelgeuse too. Raslagethi (Alpha Herculis) not so much so yeah, that one could go!)

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