I found this on yahoo answers when someone asked if 2012 was the end of the world.
I do not believe the world will end but all life on it might. Every 2,150 years we change from one star sign to another it just so happens that change will be on 21st December 2012. At the moment we are in the Pisces star sign and have been since the last Ice age. The Mayans, Babylonians and many other ancient communities found that in 2012 the world was meant to end when we change from Pisces to Aquarius. Now some scientists from the present have discovered that every 25800 years since the birth of time, there has been a catastrophe when the earth has shifted from a complete loop of the star signs. Think about the song age of Aquarius.
Source(s):
http://en.wikipedia.org/wiki/Age_of_Aquarius