Supernova Left Its Mark In Ancient Bacteria

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."

Comments

Re:One supernova of many in Local Bubble

[argStyopa]

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.