Supernova 1987A, as the supergiant explosion was called, was the first one in nearly 400 years to be visible to the naked eye. Specifically, I want to tell you about something that happened with a star nearly 30 years ago. Well, actually it happened about 168,000 years ago, but we earthlings first found out about it on 24 February 1987. In fact, a truly massive star, one astronomers call a supergiant, exploded. That halo is actually material from the star that the supernova flung into space, and it is still travelling outward at more than 7,000km per second.

Source: Mint November 17, 2016 19:49 UTC