One theory suggests a galactic alignment which would create chaos on Earth because of the gravitational effect between the Sun and the Black hole called Sagittarius A, which is located at the center of our galaxy. NASA scientists have been thoroughly studying and analyzing the possibility of the Earth ending in 2012, but concluded that 21st December 2012 it will be nothing more than a normal December solstice. n response to theories about planetary alignments leading to an apocalypse on Earth on December 21, 2012, the scientists say no planetary alignments will occur in the next few decades. But even if they did, the effects on our planet would be negligible.
NASA also says the 'polar shift' theory is totally impossible. Although continents move slowly throughout time, a magnetic reversal is very unlikely to happen in the next few millennia and wouldn’t cause any harm to life on Earth. The scientists’ conclusion is that the end of the Mayan calendar does not imply the end of the world, only the end of the Mayan long-count period.
The 'long count' is a part of the Maya calendar shaped like a wheel. When we reach the end of the wheel, it will simply turn to the beginning again, just like our modern Gregorian calendar starts again every January 1.There is simply no scientific evidence to support any claims of an apocalypse on Earth in December 2012. Another theory involves a 'polar shift', which means a reversal of the north and south magnetic poles. Scientists believe that the Earth is overdue for a geomagnetic reversal. However this can take up to 5,000 years to complete and does not start on any particular date.