Will the earth stop spinning for 3 days in december 2012 then start turning the other way round?
No. it will not happen. It is virtually impossible and if it did happen the forces involved would rip the Earth to shreds. There is no evidence of cosmic disaster 11500 years ago. However, there is evidence of the end of the last ice-age. This caused sea levels to rise about 300 feet. To the ancients this would have seemed like the end of the world, because most of their settlements would have been on the coast. The Mayan calender is going to end on the 21st December because it just ends there. it is like our calendar ends at the end of each year, then we start again. The Mayans just used a bigger cycle that’s all.