At 2004 study told us that a GRB from a distance of just one kilo parsec could destroy half of Earth's ozone layer. It suggests that historical mass extinctions may have been caused by GRBs. NASA explains how gamma-ray radiation from a relatively nearby star explosion, hitting the Earth for only ten seconds, could deplete up to half of the atmosphere's protective ozone layer.

Recovery could take at least five years. With the ozone layer damaged, ultraviolet radiation from the Sun could kill much of the life on land and near the surface of oceans and lakes, and disrupt the food chain.

Possibility this century = 7

Possibility in 2012 = 7

Could Ancients Predict It? = 5

TOTAL 19

Alien Invasion that conceive will come along 2012 is another hypothesis makes the end of the world. And the truth about alien invasion is no evidence, but plenty of trusters. Connected with this are recent clip circles that have 2012 and Mayan themes. Whenever aliens are the creators of clip circles, and so one would expect the circles to be a cautionary of sorts.

Possibility this century = 7
Possibility in 2012 = 6
Could Ancients Predict It? = 7
TOTAL 20

NASA 2012 at youtube.com — http://www.hobeze.com showed a terrific digest by revelatory issues that could bump whenever the giant meteor 'Armageddon' style come near earth target falls upon the earth. And they thought it was come at 2012