According to bible predictions, the world will not end. It was intended to be an earthly paradise filled with perfect humans who live forever. No sickness, no death, no pain. What will end is the way this world is run, with violence, bigotry, hatred, and unfairness; full of trial and sickness, death and heartache. No one knows when this end will happen. There are things you can do to make sure you are included in those who make it. Don't worry about 2012. It's nothing
There is no why is it going to end but a when is it going to end. Scientist have been trying to figure this out for along time. There are many predictions to the end on the world but none have been proven as fact.