Kahim wrote:Some also say planet X will complete a long revolution and enter our solar system to close to our plantes gravitational pull and pull it into earth destroying both wolrds completely
TL;DR: It's all bollocks, and there's some links at the bottom.
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We can detect planets that are circling other stars halfway accross the galaxy, and black asteroids further than pluto that reflect almost no light at all. We have instruments that can detect the energy released by the striking of a match on the surface of the moon (300 000km away). Objects the size of planets that are hurtling through space towards earth would be, you'd think, very easy to find.
The 2012 and Planet X (or Nibiru, or Eris, or whatever) people think it IS easy to find, but the best images they have of Planet X look something like this:
http://upload.wikimedia.org/wikipedia/commons/d/d3/V838_Mon_HST.jpgIf you're familiar with the sky at all, you'll recognise the structure instantly.

If you're asking WHY people believe the world is going to end in 2012, well... the only answer I can give you is that people are stupid. People have a habit of believing stupid things. One of those stupid things has been that the world is going to end. The worlds religions havn't helped in this regard. At least Christianity, not a small religion by any count, has a world-is-coming-to-and-end myth, when jesus returns, takes the believers to heaven, judges the living and the dead, and condemns the remainder to years of war and pestilence. Some doomsayers are of the UFO kind, that believe that ET is going to swoop down in the mothership and carry the believers to safety while the earth is destroyed.
So, people believe that the earth is coming to an end, but they have no idea when or how. There is a scramble to decide, in fact, when and how the earth is going to come to and end. Science' only answer is that the sun is going to explode in 5 billion years, and in any case the human race is going to be long gone by that time. So, obviously, science is WRONG, or it's all a gigantic conspiracy to HIDE THE TRUTH. People who fall into the former camp turn to scripture, invariably, and try to divine from century-old tomes of awful stories when God says the world is coming to an end. The people that fall into the latter camp (the tinfoil hat wearing conspiracy theorist camp) will try to work it out themselves, but basically have to make things up for the science to conform with their belief, or radically misinterpret existing scientific findings through their government cover-up lense.
Every year there's another Doomsday Prediction, and every year, on the appointed month, on the appointed day, the world promptly fails to end.
For a comprehensive list of known doomsday predictions throughout history, see
A Brief History of the Apocalypse (
http://www.abhota.info/). The most important ones (and there's A LOT) would be in the 2000 - present list. The Future predictions list is interesting for a giggle.
</rant>
For what the believers are saying about 2012 specifically, you could start at
http://www.2012doomsday.com/For the skeptics answer, you can try
http://www.skepdic.com/maya.htmlAnd don't stop there. The interwebs are full of information from all sides. Get some reading in.
