|Crab Nebula from the Hubble Telescope (Public Domain)
There is no shortage of End-of-the-World millenarian nut jobs out there, including the Y2Kers, the Mayan Long-Counters, and, more recently, those convinced a supernova will wipe out the Earth in December 2012.
Apparently NASA has gotten fed up with the pseudoscientific panic and has issued the following statement: "...astronomers can say with certainty that there is no threatening star close enough to hurt Earth."
Not to let the sanguine totally off the hook, Discovery News has published the following SLIDE SHOW: Top 5 REAL Cosmic Doomsday Events of 2011 It has some pretty good images and explanations and is worth a gander.
They also provide their own analysis why Earth is Unlikely to Be Wiped Out by a Supernova.