Scientists believe some heavy elements are forged when a massive star goes through its death throes and explodes as a supernova. Here, the supernova Cassiopeia A was captured in a false-color image from NASA. Traces of rare forms of iron and plutonium have been found at the bottom of the Pacific Ocean, after some kind of cataclysm in outer space created this radioactive stuff and sent it raining down on our planet. The extraterrestrial debris arrived on Earth within the last 10 million years, according to a report in the journal Science. Once it hit the Pacific Ocean and settled to the bottom, nearly a mile down, the material got incorporated into layers of a rock that was later hauled up by a Japanese oil exploration company and donated to researchers.