A cosmic cluster of rocks first spotted in 2011 could have spawned the Chelyabinsk meteor that exploded over Russia earlier this year, researchers say.

Scientists at Complutense University of Madrid, Spain, say they believe the culprit is asteroid 2011 EO40, a 220-yard-wide cluster of rocks previously listed as hazardous by the International Astronomical Union's Minor Planet Center in Cambridge, Mass.

Researcher Carlos de la Fuente Marcos and his brother Raul used a computer simulation to create hypothetical orbital paths around the sun that would have intersected with Earth at the time the meteor hit.

Then they searched a database of known asteroids for ones following those orbits, zeroing in on 2011 EO40.

If 2011 EO40 really is Chelyabinsk's parent, future observations should help predict if Chelyabinsk has any siblings still in orbit that might pose a threat to Earth, Carlos said.

Most asteroids aren't solid rocks but rather rock clusters that have been gradually fragmenting for eons, he said.

"Most asteroids are rubble piles, very fragile."