The Loh Down On Science

How scientists know a supernova once hit Earth

Ever wonder what an exploding star tastes like?

This is Sandra Tsing Loh with the Loh Down on Science

Saying, me, too!  Let's ask a germ!

What?  Let me back up.  Millions of years ago, a supernova went kablooey.  That star was close enough that some debris flew to Earth and sank in the Pacific Ocean.  The debris included iron-60, a radioactive isotope forged in a supernova's fiery heart.

Fast forward.  A lot!  Just ten years ago, scientists found iron-60 from that supernova in a rock on the ocean floor.  Exciting!  But it gets better. 

Physicist Sean Bishop thought:  If it's in a plain old rock, maybe it's in the fossil record, too!  So he and his team studied ancient fossil sediment dredged up from beneath the Pacific.  Lo and behold, there it was, iron-60.  Not much, but some.

How did the iron get into Earth's fossils, you ask?

GERMS!  Bishop thinks that ancient iron-loving bacteria may have digested the radioactive supernova debris.

Talk about a stellar snack!  Sorry.

***** For more 90-SECOND SCIENCE FACTS, click here.*****

The Loh Down on Science is produced by LDOS Media Lab, with 89.3 KPCC. And made possible by the generous support of the Gordon and Betty Moore Foundation.

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