There's strong evidence – including a radioactive type of iron – that supernovae occurred close to Earth between ~2m-8 million years ago. A new study shows how X-rays from such stellar explosions could threaten any life on surrounding planets for decades. https://go.nasa.gov/3op5LvX #NASAExoplanets
Astronomers have determined supernova explosions pose yet another threat to planets and their atmospheres. This result comes from analysis of X-ray observations for over 30 supernovae using NASA’s Chandra X-ray Observatory and other telescopes.
