Extraterrestrial radioactive isotope found in seabed has implications for Earth's origins. The dating of the sample confirms two or more supernova explosions occurred near Earth. "Our data could be the first evidence that supernovae do indeed produce plutonium-244."
The Next 500 Years review: Engineering humanity for life after Earth
Rare 'Alien' Isotopes in Earth's Crust Point to Recent Brush With a Cataclysmic Event
