“This is a rock, and seeing it fall apart before our eyes is pretty amazing,” said David Jewitt of the University of California at Los Angeles.
The crumbling asteroid, named ‘P/2013 R3’, was first noticed as an unusual, fuzzy-looking object late last year.
A follow-up observation revealed three bodies moving together in an envelope of dust nearly the diameter of earth.
“With its superior resolution, space telescope observations showed there were really 10 embedded objects, each with comet-like dust tails. The four largest rocky fragments are up to 400 yards in diameter, about four times the length of a football field,” explained Jewitt.
It is unlikely the asteroid is disintegrating because of a collision with another asteroid.
This leaves a scenario in which the asteroid is disintegrating due to a subtle effect of sunlight, which causes the rotation rate of the asteroid to gradually increase.
For this scenario to occur, ‘P/2013 R3’ must have a weak, fractured interior – probably as the result of numerous non-destructive collisions with other asteroids.
The asteroid’s remnant debris, weighing about 200,000 tonnes, would provide a rich source of meteoroids in the future.
Most would eventually plunge into the sun, but a small fraction of the debris may one day blaze across the Earth’s skies as meteors, scientists say.