IT CAME FROM SPACE: Celestial Events and Terran Extinctions

Space is a hostile and chaotic place, and yet on our little rock, life – as Richard Attenborough famously said – finds a way. Unless a gentle shift in stellar fortune BRUTALLY DESTROYS IT.

We know about the threat of comets, aliens, the inevitable nova-ing of our star and the eventual heat death of the universe, but space also has some more subtle tricks…this post explores one of them.

Two million years ago a slightly underwhelming marine extinction event occurred: fossil evidence shows a mass death of molluscs and Plankton which is considered to be the marker between the  Pliocene and Pleistocene epochs. What puzzled palaeontologists who studied this extinction was that it occurred in conjunction with a spike in levels of the iron isotope 60Fe in the sediments where these fossils were found. Were the extinction and the isotope related?

Phytoplankton By NOAA MESA Project (http://www.photolib.noaa.gov/bigs/fish1880.jpg [1]) [Public domain], via Wikimedia Commons

Phytoplankton By NOAA MESA Project (http://www.photolib.noaa.gov/bigs/fish1880.jpg [1]), via Wikimedia Commons

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