The team was surprised to find a strange element in the ice: iron 60. This version of iron is produced in only two known places. It is the product of nuclear reactions such as those that occur in reactors. The scientists knew, given the prevailing winds, and the great distance between any nuclear reactors and the Kohnen Station, that a nuclear plant was not the source. The only remaining possibility was that the iron 60 came from a large supernova in outer space.
