That's petty funny timing. One of the guys at work just loaned me a copy of 'Worlds in Collision', insisting that I read it. When I can point out 3 or 4 massive flaws in the guy's cosmology within chapter 1, it doesn't promise to be a very well supported hypothesis.
I love this bit, from your one link:
When Comet Elenin first was discovered in December last 2010 it was calculated to pass 8.8 Au (8.8 times the distance of the Sun form us) away. But now these calculations has once changed again. Today the orbital calculation is down to 0.24 Au with a minimum as low as 0.15. But these data is being recalculated all the time and it could get even closer but that depends what it encounters in the Oort belt. Just so you know the Moon is 0.00256 away from us to give you a comparison.
Sooooo ... what you're telling me is that I should be panicking because a comet is going to pass within FIFTY-NINE times the distance from the earth to the moon? Not panicking over here.
So, what's this Nibiru stuff? I'm still doing searches for stuff, over here.