Did you hear that whooshing sound? A few hours ago a ‘small’ asteroid (30 metres across) flew past the Earth, missing by just 60,000 km (roughly twice the altitude of orbiting communication satellites).
This little cosmic surprise, designated 2009 DD45, turned up two days ago as a 19th-magnitude blip in images taken by Rob McNaught at Siding Spring Observatory in Australia. It was already within 1½ million miles of Earth and closing fast.
Thankfully, the news media have become less sensationalistic when it comes to these asteroidal close calls — especially since one actually struck our planet last October 7th, at night, and the impact went virtually unnoticed.
I’m not sure whether the lack of sensationalism is a good thing. Perhaps we *should* be shocking people into considering the possible threat from space impacts. As the article points out, this asteroid was spotted for the first time *two days ago* – an amount of time for which the countermeasures probably translate into “get the hell out of there”. Although, as Phil Plait mentions, at least we are spotting them – it’s now a matter of working out how we deal with them when spotted (and perhaps it would be nice to spot them a little earlier…).
For a primer on the danger of asteroids, and every other menace from space, see the Bad Astronomer’s book Death from the Skies (Amazon US and UK).
