The red supergiant star Betelgeuse is getting ready to go supernova. The explosion will be so bright that Earth will briefly seem to have two suns in the sky. From

The star is located in the Orion Nebula, about 640 light-years away from Earth. It's one of the bright and biggest stars in our galactic neighborhood - if you dropped it in our Solar System, it would extend all the way out to Jupiter, leaving Earth completely engulfed. In stellar terms, it's predicted to explode in the very near future. Of course, the conversion from stellar to human terms is pretty extreme, as Betelgeuse is predicted to explode anytime in the next million years.

Whether the explosion occurs in 2011 or 1002011, it's going to make for one of the most unforgettable light shows in our planet's history. For a few weeks, the supernova will be so bright that there will appear to be two stars in the sky, and night will be will indistinguishable from day for much of that time. Indeed, just in case anyone is concerned, Betelgeuse is way too far away from Earth to do us any damage. There's been some doomsday speculation of late around the eventual supernova - which might not happen for a million years, it bears repeating - but, as with pretty much all doomsday speculation, you can just ignore it.