There are a lot of information about the December 21, 2012. Mayan calendar and others seen as the end. Gregorian calendar has been built to serve sheckle. A number of other things done to make appropriate at different times in the history of the earth. Now we think that the date of the end of the calendar, meaning the last chance is part of that created by illsuion calendar that we use. We tend to think there is certainty in it. First let's look at a real example of the natural cycle. Now astrology somewhat accurate, also not a true cycle in balance with our galaxy. There are actually 13 constellations in the sky, which marks the birth of 13, not 12 we are told there. Birth signs are taken 12 to 12 months in accordance with the Gregorian calendar. Out of sync? Yep, another part of illsuion. Lost or removed constellations, but perhaps the most important thing is Ophiuchus. (aka The Snake Holder interesting part metaphysical energy).
Two important things are not so strange is the fact that the use of Maya 13, not 12 months in their calendar and the moon made out of 13 trips around the planet once a year. We''ll use sunsign Aries. Usually if you were born in Aries, then from (using the 12 astrological signs are not normal) March 21 to April 21 of any given year. Some think if you were born on Apr.22, you then Taurus, because Aries ended. It is known as many know a tipping point. The influence of one or other marks overlap days / hour / minute.
Sunsign period in mid-Aries, you can be a stronger influence, but even that can not be responsible as a predictor of eliminating the influence of other planets that also affect people at that time. Some effects can be deadly even planetry many people who should be Aries, others can strengthen it. This is not now and will never be cut and dry, but not exactly one of the 13 constellations of astrology and professional. Even then the best estimate they will give you, is' the influence of that period, not the results. That's up to you and how you deal with the effects. And for this, we do not really need astrology, we just need to learn to deal with the effects.