March 6, 2014 - The break up of an asteroid
has been captured on film for the first time.
Experts pictured the P/2013 R3 asteroid breaking into ten pieces using Nasa's Hubble space telescope.
Publishing details in Astrophysical Journal Letters, they said that although fragile comet nuclei have been seen falling apart as they near the sun, nothing resembling this type of breakup has been observed before in the asteroid belt.
The pictures show the asteroid splitting up into smaller fragments between October last year and mid-January.
The four largest are up to 200 yards in radius, the astronomers said.
They said the asteroid's debris will provide a "rich source of meteoroids" in the future. While most will plunge into the sun, a small fraction may one day enter the Earth's atmosphere as meteors.
"Seeing this rock fall apart before our eyes is pretty amazing," said Professor David Jewitt, of the University of California, Los Angeles. Fragments were seen drifting away from each other at about one mile an hour.
The astronomers said the asteroid began coming apart early last year, but new pieces continue to emerge.
They said it was unlikely that the asteroid is breaking up because of a collision with another, because that would have caused an "instantaneous and violent" break up.
They said that the break up is also unlikely to have been caused by interior ices warming and vapourising because it is too cold – being nearly 300 million miles from the sun.