I was expecting more reaction to my recent post about global warming and extinction level events, but I got much less mail about that than I did regarding my post talking about the recent Apple iPhone rumours.
Then you get a close call, and an asteroid passes near by and you end up with a bucket load of mail in your inbox.
While it was pretty small at only 5 meters, and would probably have entirely burned up in the atmosphere depending on the composition, 2004 YD5 passed below geostationary orbit and was the second closest asteroid approach ever observed. The closest involved 2004 FU162 that flew by last March which we didn't even spot until August.
2004 YD5 was discovered on December 21st by Stan Pope of the FMO project, but it was later calculated that closest approach had been two days earlier on December the 19th. So, like the other one we only saw this one after it had gone by as there is a significant blind spot for people trying to detect NEOs. As, just like all those old war films with aerial dog fights, they come at you out of the sun. This isn't very reassuring...
Like all the other near misses, this one illustrates that we really should be doing more to detect near-Earth asteroids before they become a threat. It's always suprised me that the Shoemaker-Levy 9 impact with Jupiter in 1994 didn't cause more comment. After all, what sensible species would watch a rock the size of a large mountain strike a nearby planet and then do absolutely nothing about it?