How to prevent asteroid collision with Earth

September 14th, 2010 - 4:45 pm ICT by ANI  

London, Sep 14 (ANI): Researchers at Tel Aviv university have got a clue that could help in developing a defensive strategy in case an asteroid were on track to collide with the Earth.

Although it was once believed that all asteroids are giant pieces of solid rock, later hypotheses have it that some are actually a collection of small gravel-sized rocks, held together by gravity.

If one of these “rubble piles” spins fast enough, it’s speculated that pieces could separate from it through centrifugal force and form a second collection — in effect, a second asteroid.

Now Tel Aviv researchers, in collaboration with an international group of scientists, have proved the existence of these theoretical “separated asteroid” pairs.

Ph.D. student David Polishook of Tel Aviv University’s Department of Geophysics and Planetary Sciences and his supervisor Dr. Noah Brosch of the university’s School of Physics and Astronomy have said that the research has not only verified a theory, but could have greater implications if an asteroid passes close to Earth.

Instead of a solid mountain colliding with Earth’s surface, says Brosch, the planet would be pelted with the innumerable pebbles and rocks that comprise it, like a shotgun blast instead of a single cannonball.

This knowledge could guide the defensive tactics to be taken if an asteroid were on track to collide with the Earth.

Brosch said that separated asteroids are composed of small pebbles glued together by gravitational attraction.

Their paths are affected by the gravitational pull of major planets, but the radiation of the Sun, he says, can also have an immense impact.

Once the Sun’s light is absorbed by the asteroid, rotation speeds up. When it reaches a certain speed, a piece will break off to form a separate asteroid.

The phenomenon can be compared to a figure skater on the ice.

“The faster they spin, the harder it is for them to keep their arms close to their bodies,” Nature quoted Brosch as saying.

As a result, asteroid pairs are formed, characterized by the trajectory of their rotation around the Sun. Though they may be millions of miles apart, the two asteroids share the same orbit.

Brosch said that this demonstrates that they come from the same original asteroid source.

The study has been published in the journal Nature. (ANI)

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