I used to check the NASA/JPL tables now and then just out of idle curiosity, and kind of got into it back when Apophis first hit the news. Assuming they would actually post the truth about a pending cataclysmic collision (Giving no odds on that one), there doesn't appear to be any predicted risk of a known kilometer-plus sized object hitting the Earth for the foreseeable future, aside from an uncertainty about what track Apophis will take after its next near approach (It's a miss, but so close Earth's gravity will have an unpredictable effect on its subsequent trajectory, and there is a small window it may go through which would bring it back around for a true hit later.
However however however....
Both Apophis and a couple of other large objects over a kilometer in size DO pass within a Lunar orbit of Earth this Century. Passing inside the Lunar orbit actually raises two possible collisions with the Moon per close approach. Imagine the consequences of an object, especially a metallic one, smacking into the Moon at a few Ks per second, and where a lot of the collision ejecta is going to go....
I expect I'll be checked out by the time these things become an immediate issue, so this is more of an academic interest than a real one. Thoughts?
