This is a myth based on the irresponsible, (and repeated) airing of a ridiculous pseudo-documentary on the History Channel. That network, and the Discovery Channel and Fox, will air anything they feel will get a bigger audience. Sometimes, their shows are good and worth watching. Other times, they are foolish, sensationalist, tabloid-style hype. It is often difficult to tell which is which, unless you know about a subject. I know about the history of doomsday predictions, pseudoscience, and astronomy.
The Mayan calendar does not predict the end of the world. They did keep an accurate calendar, but contrary to popular opinion, never predicted any world event accurately. They couldn't predict their own demise; why should they be able to predict ours?
The alignment with the galactic center is not going to happen. It comes fairly close to happening EVERY year on Dec 21, and will be exactly the same as it always is, in 2012. Even if some perfect alignment did occur, there is nothing about it that could affect the earth. It's like saying, "When these three parking spaces are occupied by three red cars, the world will come to an end."
Doomsday prophets have always been around and they are always wrong. Every 5 to 10 years, some prediction catches the public's attention and scares a lot of kids...usually thanks to irresponsible media decisions. Dozens of different doomsday scenarios have been piggy-backed on to this date since the show aired. Go to this site to see how many predicted apocalypses we have already missed.
http://www.abhota.info/index.htm
All that Nibiru stuff is bunk, too. No such planet has ever been discovered. The claim that it was discovered some 25 years ago is not true.
