And even more from Wikipedia on the 2012 doomsday that never happened and was mostly made up by American new-age drug addicts:
Some people interpreted the galactic alignment apocalyptically, claiming that its occurrence would somehow create a combined gravitational effect between the Sun and the supermassive black hole at the center of our galaxy (known as Sagittarius A*), creating havoc on Earth. Apart from "galactic alignment" already having happened in 1998, the Sun's apparent path through the zodiac as seen from Earth does not take it near the true galactic center, but rather several degrees above it. Even if this were not the case, Sagittarius A* is 30,000 light years from Earth; it would have to be more than 6 million times closer to cause any gravitational disruption to Earth's Solar System. This reading of the alignment was included on the History Channel documentary, Decoding the Past. John Major Jenkins complained that a science fiction writer co-authored the documentary, and he went on to characterize it as "45 minutes of unabashed doomsday hype and the worst kind of inane sensationalism".
Some believers in a 2012 doomsday used the term "galactic alignment" to describe a different phenomenon proposed by some scientists to explain a pattern in mass extinctions supposedly observed in the fossil record. According to this hypothesis, mass extinctions are not random, but recur every 26 million years. To account for this, it suggests that vertical oscillations made by the Sun on its 250-million-year orbit of the galactic center cause it to regularly pass through the galactic plane. When the Sun's orbit takes it outside the galactic plane which bisects the galactic disc, the influence of the galactic tide is weaker. However, when re-entering the galactic disc—as it does every 20–25 million years—it comes under the influence of the far stronger "disc tides", which, according to mathematical models, increase the flux of Oort cloud comets into the inner Solar System by a factor of 4, thus leading to a massive increase in the likelihood of a devastating comet impact. However, this "alignment" takes place over tens of millions of years, and could never be timed to an exact date. Evidence shows that the Sun passed through the plane bisecting the galactic disc only three million years ago and is now moving farther above it.
A third suggested alignment was some sort of planetary conjunction occurring on 21 December 2012; however, there was no conjunction on that date. Multi-planet alignments did occur in both 2000 and 2010, each with no ill result for the Earth. Jupiter is the largest planet in the Solar System; larger than all other planets combined. When Jupiter is near opposition, the difference in gravitational force that the Earth experiences is less than 1% of the force that the Earth feels daily from the Moon.