Coozer Prophesy: Asteroid to hit Earth in 160 years?

Well, at least we don't have to worry about the environment now... From New Scientist:

AN ASTEROID that had initially been deemed harmless has turned out to have a slim chance of hitting Earth in 160 years. While that might seem a distant threat, there's far less time available to deflect it off course.

Asteroid 1999 RQ36 was discovered a decade ago, but it was not considered particularly worrisome since it has no chance of striking Earth in the next 100 years - the time frame astronomers routinely use to assess potential threats.

Now, new calculations show a 1 in 1400 chance that it will strike Earth between 2169 and 2199, according to Andrea Milani of the University of Pisa in Italy and colleagues (www.arxiv.org/abs/0901.3631).

With an estimated diameter of 560 metres, 1999 RQ36 is more than twice the size of the better-known asteroid Apophis, which has a 1 in 45,000 chance of hitting Earth in 2036 (New Scientist, 12 July 2008, p 12). Both are large enough to unleash devastating tsunamis if they were to smash into the ocean.