We now have a new explanation for an unexplained extinction event about 440 million years ago – cosmic rays. Now, while that might sound friendly, since we exist on this planet based on the fruits of the Sun’s energy, it’s not. This particular type of cosmic ray is called a gamma ray burst, and it’s what happens when a supernova explodes. It’s the greatest short term destructive weapon nature has in its arsenal, and makes nuclear bombs look cute and fuzzy by comparison.
We’ve known there are several clusters around us that have let of Gamma Ray Bursts while humans have been alive, but thankfully they’ve been pointed in other directions. It appears that when one was pointed our way, most of life on earth died out, and only the small creatures or the very prolific survived.
With luck, humanity won’t be sitting all in one basket when the next arrives.