Asteroid collision

The Nordic Optical Telescope, located in the Canary Islands has detected an strange object located at 2.25 astronomical units from the Sun.
This observation was confirmed two nights later with the Gran Telescopio Canarias, off 10.4 m. The asteroid P/2010 A2 is approximately 120 m wide and orbit between Mars and Jupiter in the asteroid belt.
It's January 6, 2010, Hubble showed that it was an asteroid adorned with a long filament of debris.
Thanks to the Hubble Space Telescope took images of this event between January and May 2010, NASA was able to announce that this was due to a collision of two asteroids that occurred in early 2009.
The long tail of 50 000 km, the asteroid P/2010 A2 consists of particles with diameters ranging from one millimeter to 2.5 centimeters. The asteroid that struck P/2010 A2 is much smaller, it measures from three to six meters wide (journal 'Nature' on 14 October).
The two celestial bodies have faced nearly 18 000 km/h. The impact smashed the smallest asteroid and reduces the weight of the largest.
According to David Jewitt, an astronomer at the University of California at Los Angeles, the collision occurred in February or March 2009.
The collision itself was not observed. 

The event is not rare but the observation of such an event is lucky because small asteroids collide about once a year in this area.
When these shocks asteroids lose mass by ejecting dust into interplanetary space.
Astronomers rely on computer models to predict the frequency of collisions and the volume of dust produced.
"These observations are important because we need to know where does the dust of the solar system and the part resulting from collisions between asteroids compared to that from comets as they pass," says David Jewitt.
Although the pictures from Hubble show evidence of a collision between two asteroids, David Jewitt believes it does not have enough information to rule out other explanations for this strange object.

NB: The Lincoln Near-Earth Asteroid Research (LINEAR) is a joint research project of the U.S. Air Force, NASA and MIT's Lincoln Laboratory.
LINEAR robotic telescopes have detected the December 31, 2007, 225,957 asteroids, 2 019 comets and 236 objects cruisers.