Radioactive debris from supernova blasts discovered in ocean crust

Two massive explosions, 2.2 and 1.5 million years ago, could have been as close as 300 light years distant, and would have been visible from Earth Radioactive shrapnel from one of the biggest blasts in the universe – a supernova explosion – has been identified in the ocean crust. The evidence is a scatter of a rare isotope of iron that could only have come from an exploding star.Scientists think the explosions – they believe there must have been at least two – could have