Supernova Remnants Likely Captured By Ancient Deep Sea Bacteria

If scientists are correct about a certain iron-loving deep-sea bacteria, then their fossilized remains hold iron traces from a supernova that exploded 2.2 million years ago.

The find would mark the first biological signature of an exploding star found on Earth, Nature reports.

Physicist Shawn Bishop based his research on the 2004 findings of the isotope iron-60, which does not form on Earth, in a chunk of sea floor from the Pacific Ocean. The scientists who discovered the iron-60 concluded it must have come from a supernova.

Bishop and colleagues took samples of ocean core dating between 1.7 and 3.3 million years ago and took samples every 100,000 years in the rock, treating the samples with chemicals that would isolate only the iron-60.

The only place they could find traces of the iron-60 was in sediment samples dated around 2.2 million years old.

According to Nature, "This apparent signal of iron-60, Bishop said, could be the remains of magnetite (Fe₃O₄) 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."

Bishop, a physicist at the Technical University of Munich in Germany, reported preliminary findings on April 14 at a meeting of the American Physical Society in Denver, Colo.

"For me, philosophically, the charm is that this is sitting in the fossil record of our planet," Bishop said.