There is going to be no doomsday event in 2012. When something ends (even something as innocent as an ancient calendar), people seem to think up the most extreme possibilities for the end of civilization as we know it.
When astrologers speak of the planets being aligned (something which doesn't really concern astronomers) they don't mean that the planets will actually all lie on a straight line at some instant of time. One calculation of alignments within around thirty degrees (about as close as they can get) shows that the last such alignment was in 561 BC, and the next will be in 2854. All eight planets are somewhat aligned every 500 years, and are grouped within 30 degrees every 1 to 3 alignments.
There is absolutely no scientific evidence supporting the claim that there could be a geomagnetic reversal around the time of December 21st, 2012.
the effects of such a reversal have been totally over-hyped.
We'll most likely experience aurorae at all latitudes whilst the dipolar magnetic field settles down to its new, reversed state, and there might be a small increase in energetic particles from space
we'll still be protected by our thick atmosphere.
Nostradamus was, by profession, an apothecary – which, in modern terms, is a pharmacist.
The predictions of Nostradamus can be compared to that of an arrow being shot at a blank wall on which the believers paint a target around its landing!