As far as I percieved it until now every question on Skeptics.SE should question a certain claim or (better and) provide sources for that claim (unless it is a widely know one).
The question about chances that an asteroid will hit the earth has neither a claim that this happens or a source for a statement like that. I actually think that this is an interesting topic to discuss, but there were other interesting topics that got closed down very quick (because there were no skeptic claims).
I voted for closing the question, the vote got marked als helpful, yet moderators and high rep members supply answers to the question. I don't think that it would be good to actually close the question any longer, but it should be moved to astronomy.SE.