It’s almost like a cosmic hurricane warning signal… From Bad Astronomy: “So, what’s the deal with Betelgeuse? What is it, will it explode, and if so, when?”
The constellation Orion’s biggest star is Betelgeuse (pronounced “beetle-juice”), a red supergiant, and it’s one of the brightest stars in the sky - that’s the “what”.
Will it explode? Well, according to some observers, the star is not round, and it’s getting smaller. This could be the signs of Betelgeuse heading toward a supernova phase, but it also could be explained away by large sunspots that fool our observations.
Bad Astronomy seems to think that this is likely an astronomical doomsday rumor. It may be interesting only because it’s close to the 2012 doomsday date that is the end of the Mayan calendar. But read the Bad Astronomy article for yourself to get the best information on the topic.