Jupiter under 'asteroid' attack for third time in 13 months

Two Japanese amateur astronomers have discovered a comet or asteroid strike on Jupiter -the third time the giant planet has been bombarded in 13 months.

The observations show that impacts on the giant planet occur more frequently than previously thought.

The last two attacks occurred in June 2010 and July 2009.

Before these three events were recorded, the only definite case of an asteroid or a comet colliding with Jupiter was in 1994 - a collision with fragments of comet Shoemaker-Levy 9.

So many observations in such a short period is probably because of a technique that makes sharp still images by combining the clearest frames from a video recording, says Glenn Orton of NASA's Jet Propulsion Laboratory in Pasadena, California.

"The results are quite impressive," New Scientist quoted Orton as saying.

Orton and a group of astronomers led by Australian amateur Anthony Wesley have suggested setting up a worldwide network of small, automated telescopes to continuously monitor Jupiter for impacts.