Earth dodges yet another one
Yesterday morning at about the time my daughter was dancing her “snow day” dance – about 8:45 am – a rock 2/3rd the length of a football field was sailing past the Earth at a range of 40,000 miles. The asteroid was discovered by Australian astronomers last Friday.
2009 DD45, as the asteroid is tagged, was about 200 feet wide. While 40,000 miles sounds like a lot, that’s well inside the circle of the Moon’s orbit and just under twice the altitude of our telecom satellites. Should it have hit, its size would have pretty much guaranteed that it would make it to the ground (or close enough for jazz) and its impact would have looked like a large nuke going off. We’d have had 3 days notice that it was going to happen.
Exit question: think we can evac a large city to safe distance with 3 days’ notice?
Comments
Comment from Ric James
Time March 4, 2009 at 10:36
Well, this was no pebble, by any measure, but it’s not the extinction-level rock either. According to the story, it would have been the equivalent of a large nuke, so you should think of the hydrogen bombs set off by us and the Russians during the cold war tests. Those were big – the largest was somewhere close to 100 Megatons – but they didn’t produce the kinds of comet-strike effects you’re talking about. Based on that, I believe this one wouldn’t have, either. Still, having that come down in New York or London or Sydney would have been Very Bad™.
It’s the lack of advanced warning that concerns me. To say nothing of the loss of life and damage done, if a city suddenly went *poof* in something that looked just like a big nuke strike, and that city had been, say, Tehran we might see a shooting war touched off by a natural disaster.
Comment from Bob James
Time March 4, 2009 at 09:53
Safe distance? In this context, given the wave effects of the impact (land or water, doesn’t really matter) and the ejecta into the atmosphere, what is “safe distance”?