Near Earth Objects, such as the Geminids’ 3200 Phaethon, don’t just pose a potential risk to Earth. One NEO, 2007 WD5, was only identified on 20 November this year and, having been eliminated as a potential threat to Earth, is now heading towards Mars – ETA 30 January 2008. Interactive 3D orbit diagram here [Java req].
NASA astronomers calculate that the chance of a collision with Mars, by the approximately 50m wide asteroid, is currently 1 in 75, although there is still work to do to refine those odds. Listen to astronomer Steve Chesley in this NASA podcast [transcript and mp3 file] and you might get the idea that he’s hoping it will strike the red planet.. as any curious scientist would..
Narrator[Jane Platt]: OK, so a good chance it will miss, a very good chance it will miss. But nonetheless, 1 in 75 chance that it will hit Mars is pretty high, right?
Chesley: This is a very high impact probability for what we’re used to dealing with, which is usually in the one in a million, even one in a billion odds. So 1 in 75 is certainly startling for us, and we’ve been paying close attention to this object since as soon as we realized that it was going to come so close to Mars.
NASA have provided a useful animated gif to illustrate the uncertainty involved in calculating the position of 2007 WD5 when it crosses Mars orbit
And here’s another short NASA animation showing the possible area of collision on Mars of asteroid 2007 WD5 on 30 January 2008.
But, as Jane Platt in the earlier linked podcast pointed out, “OK, so a good chance it will miss, a very good chance it will miss.”
“But nonetheless, 1 in 75 chance that it will hit Mars is pretty high, right?”