Approximately 2.6 million years ago (Pliocene epoch), a tsunami of cosmic energy from a massive supernova or a series of them about 150 light-years away reached Earth and pummeled the atmosphere, touching off climate change and triggering the mass extinction of large marine animals, according to University of Kansas Professor Adrian Melott and co-authors. An artist’s rendition of a supernova explosion. Image credit: ESA / Hubble / L. Calcada / NASA’s...