An amateur astronomer in Australia has discovered that the planet Jupiter was struck recently by an object up to two kilometres in diameter.
Anthony Wesley noticed what he described as a black scar near the south pole of the planet last Thursday.
He reported his observations to Nasa's jet propulsion laboratory in California, where astronomers were able to determine that it was caused by an impact, possibly a stray comet or a block of ice.
Nasa officials say the dent created in Jupiter is about the size of Earth.
First broadcast 22 July 2009