Astronomers re-assess comet threat

Astronomers re-assess comet threat

The Australian National University (ANU) has discovered the chances of a comet hitting earth are lower than previously thought.

ANU astronomer Paul Francis says new research shows the previous estimates, which were based on work by amateurs, are actually more accurate than originally thought.

He says this implies the chances the earth will be hit by a comet is seven times lower than previously expected.

"We've also found that most of the comets seem to be close to the sun and not far away which is not what we expected at all," he said.

"Theory predicts that for every big comet there should be 100 small comets, we're actually finding for every big comet there's only one small comet, which also doesn't make sense."

Mr Francis says new telescopes have allowed professional astronomers to do more accurate research.

"It used to be the case that professional astronomers couldn't really study, find comets because our telescopes were enormously powerful and could only look at really tiny bits of the sky," he said.

"So there could be any number of comets going from anywhere else and you'd missed them [but] what's happened in the last few years [is] they've built huge robotic digital areas of the sky and [this helps] find comets."

http://www.abc.net.au/news/newsitems/200509/s1455825.htm