A bear of little brain asks...
A bear of little brain asks: where is this 'rain of Iron-60' coming from?
Is this ejecta from the supernova, travelling at something close to the speed of light, so that it gets to the Earth only a few thousand years after the radiation - close enough that the two appear to be more or less the same in the fossil record?
Or is it a reaction that takes place on Earth - the supernova radiation striking an atom (regular Iron presumably?) and converting it to Iron-60 on Earth?
A cursory Google doesn't seem to offer an explanation and my knowledge of chemistry is so little that I'm not sure what else to search under.
Biting the hand that feeds IT
