Supernovae showered Earth with radioactive debris
https://phys.org/news/2016-04-supernovae-showered-earth-radioactive-debris.html Supernovae showered Earth with radioactive debris by Australian National University An international team of scientists has found evidence of a series of massive supernova explosions near our solar system, which showered the Earth with radioactive debris. The scientists found radioactive iron-60 in sediment and crust samples taken from the Pacific, Atlantic, and Indian Oceans. … Supernovae showered Earth with radioactive debris