You probably almost recognize
this night sky painting, but see that it isn't quite right. It's a depiction of a Christmas Day gamma-ray burst, modelled on Van Gogh's famous “Starry Nightâ€.
On Christmas Day 2010, NASA's Swift observatory detected a gamma-ray burst (GRB). We can't see gamma rays, so need special detectors. They are most powerful radiation that we know of and when they are given off, we know that a really massive explosion has happened somewhere.
Astronomers are still not too sure what caused this GRB. There were two main theories at the time – and since then a third has been proposed. I'll settle for being glad that whatever happened it was a long way, as a nearby GRB would definitely be Very Bad News for
us.