For years, researchers have puzzled over evidence that a supernova exploded somewhere in Earth's vicinity a couple of million years ago.
Now, a new study presents additional evidence of a supernova explosion near Earth 2.5 million years ago.
The 60Fe found on the Earth is potential evidence of a supernova explosion in Earth's rough vicinity.
Because its half life is 2.6 million years, any 60Fe on Earth should have decayed into nickel long ago.
So it's possible that the 60Fe found on Earth came from one of these within the last few million years, rather than a supernova.
And its presence means there definitely was a supernova explosion in Earth's vicinity, about 2.5 million years ago.
And while this SN was mostly just a close call for life on Earth, it's also a good reminder that Earth will be in the suspected kill-zone of a supernova once every 800 million years. »