That may not sound very big but it was an asteroid of a similar size that famously flattened 800 square miles of forest in Tunguska, Siberia in 1908. In the Tunguska case, it is believed the damage was caused, not by striking the Earth, but by exploding approximately 5 miles above the Earths surface.
In the near-miss on Monday the asteroid whizzed by the Earth as close as 44,750 miles, that may not seem that close, it's actually a fifth of the distance of the Moon from Earth, or to put it another way it skimmed the Earth at an altitude only twice the distance of satellites in geosynchronous orbit!
Earth has of course been littered by impacts, although fortunately for us, but not so fortunate for the Dinosaurs, mostly before Human civilisations evolved. In recent years, aside from the aforementioned Tunguska incident there have been many 'near' Earth impacts including a very close asteroid in 2004 passing us at a breath-taking 4,000 miles.
On the plus side, there are many groups and individuals monitoring the skies for Earth approaching asteroids. Indeed Mondays asteroid, now officially named '2009 DD45' was first spotted by the Siding Spring Survey in Australia who exist specifically to search for near-Earth objects. It's also reassuring to know that the UN has in place a Working Group on Near-Earth Objects, set up to draft procedures for handling the threat of asteroids. This is all very well, imagine there is an asteroid on a path likely to plough straight into the Earth, the UN have put together a plan and that plan is implemented. So far, so good. Or is it? This brings me to my main concern, when asteroid 2009 DD45 was first spotted, it was less than two days before the asteroid reached it's closest point to the Earth. I'm not sure but I don't thing 48 hours would give us adequate time to give Bruce Willis a call and get him to do his stuff.
This seems to me to be an area of space research and investigation which could genuinely do with a little more attention and I would guess, a lot more cash.
[Source: BBC News]