I skimmed through most of the replies as much as I could, so sorry if someone's already mentioned this, but:

I've looked this up before a couple of months ago, after much discussion with family about the year 2012. This end-of-the-world scenario is mentioned on the website Exit Mundi (you can google it for the URL). There, one of the things mentioned in the article that makes the scenario seem less likely (from a scientific standpoint) is that if a planet such as this had had this elliptical for so long, it would eventually swing loose from our solar system and fly off into space. The article is a good read and cites things for and against it.

But that doesn't mean it can't happen. There are some things in this universe that physics can't explain (try as they might) and stranger things have happened, so I'm definitely not ruling it out.

There is growing feeling amongst people friendly with the earth (Gaia) that the earth has "conciousness" as indeed does all created matter, and the earth will only tolerate so much rape and pillage of her/his/its? body before acting in self defence and squirting a few million of us pesky humans away in order to protect herself. The cause of world wide floods and fire from heaven in so many cultures suggests that comet strikes in the past have caused massive global changes and it is the most likely way things will get interupted in the future.  Twin earth scenarios are way down on the list of likely causes for disruption.  Scientists have been powering up satelites with a deadly little thing called plutonium generators for thirty years now. Plutonium being one of the most deadly poisons to mankind.  When the sattelites decay in orbit and they generaly do, everything in them gets incinerated by the heat of re entry.  This scatters deadly plutonium dust into our atmosphere where its slowly falls to earth so we and all other living things can eat it from our food chains.  The immense damage can never be cleaned up as the half life of plutonium is measured in thousands of years. The changes this is causing in our genes is already being measured and ghastly effectys worse than the thalidomide horror are upon us already.  When we wake up to what is slowly mutating within our very dna we may very well cry out to the "gods" to give us all a quick mercifull death in 2012 and the prophecys may be our mercifull end.
Or not!

The one thing to consider is if this is not just some small planet, but sister star, even if brown dwarf, what is mass. If mass is great enough would not fling off.

I got as far as King Enki, and couldn't read more.  That's the name of an ancient Sumerian god of the sea...  Give me a break.

Enki... yeah, that's what I first thought of when reading the thread. Btw, about floods, the Sumerian legend when the Gods flood the Earth and they watch from ?space? what happens there might be of some help?

I, for one, don't know what to think about all these theories... We'll just live and see, whatever it will be (or won't be), I for sure am gonna live my life till that and beyond (if possible).