Smashed asteroids may be related to dinosaur killer

Astronomers have found a comet-like object they believe was created by the collision of two asteroids, possible siblings of the rogue rock blamed for killing the dinosaurs millions of years ago.

The object, known as P/2010 A2, was circling about 144 million kilometres from earth in the main asteroid belt between Mars and Jupiter when it was spotted last week by the Hubble Space Telescope.

"The truth is we're still struggling to understand what this means," lead scientist David Jewitt with the University of California at Los Angeles, said. "It's most likely the result of a recent collision between two asteroids."

If so, he said, "It'd be the first case we've seen of an asteroid smash happening, basically caught in the act."

The object resembles a comet, but its nucleus is severed from its tail, which "has a very strange appearance, the likes of which we've never seen before," Mr Jewitt said.

Studies of the object - and searches for similar ones - would improve scientists' understanding of how asteroids break apart, information that may be useful to thwart a future asteroid strike on earth.

"The thing that we want to understand is how the asteroids smash into each other and destroy each other," Mr Jewett said. "It might help us understand even how to destroy an asteroid and prevent one from hitting us."

Scientists believe a giant comet or asteroid that hit earth about 65 million years ago was linked to the extinction of the dinosaurs, possibly by throwing up dust or chemical clouds that blocked the sun or by igniting global wildfires.