When Asteroids Collide

P/2010 A2
Image Credit: JPL / NASA

The Hubble telescope, in a rare peek into our own Solar System, garnered this image. JPL / NASA report that “a mysterious X-shaped debris pattern and trailing streamers of dust that suggest a head-on collision between two asteroids”.

The new Wide Field Camera 3 (WFC3), which was placed on board Hubble by last years final Space Shuttle servicing mission, took these images on 25 and 29 January 2010. The object was about 180 million miles from the sun and 90 million miles from Earth.

The Lincoln Near-Earth Asteroid Research (LINEAR) sky survey first observed this object on 6 January 2010. The initial reaction was that this was a rare main belt comet. That is, a comet orbiting in the asteroid belt between Mars and Jupiter.

“This is quite different from the smooth dust envelopes of normal comets,” says principal investigator David Jewitt of the University of California at Los Angeles. “The filaments are made of dust and gravel, presumably recently thrown out of the nucleus. Some are swept back by radiation pressure from sunlight to create straight dust streaks. Embedded in the filaments are co-moving blobs of dust that likely originated from tiny unseen parent bodies.”

The Kuiper belt and the Oort cloud are the normal origins for comets in our Solar System. When a comet is disturbed and it begins its fall toward the Sun, ice near the surface vaporizes and ejects material from the solid comet nucleus via jets. However, this object is not following such a path.

This leaves open the possibility that there has been a collision between two asteroids:

Asteroid collisions are energetic, with an average impact speed of more than 11,000 miles per hour–five times faster than a rifle bullet. The main nucleus of P/2010 A2 would be the surviving remnant of this so-called hypervelocity collision.

P/2010 A2
Image Credit: NASA, ESA, and D. Jewitt (University of California, Los Angeles). Photo No. STScI-2010-07 [larger image]

David Jewitt notes that “The filamentary appearance of P/2010 A2 is different from anything seen in Hubble images of normal comets, consistent with the action of a different process”. Ground based observations indicate there is no large envelope of gaseous products, which are typical of comets.

100 million years ago, a collision of two asteroids produced the Flora asteroid family. There is speculation that this collision may have produced the fragment that struck the Earth 65 million years ago, triggering a mass extinction that wiped out the dinosaurs. This is the first direct evidence of an asteroid collision.

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3 thoughts on “When Asteroids Collide

  1. Pingback: Smashed asteroids may be related to dinosaur killer – Reuters | .:: MrCoi Blog ::.

  2. Pingback: Asteroids Collide Nasa | Hubble, sky survey catch rare asteroid crash, NASA says | imacroautobots.com

  3. Pingback: When Asteroids Collide – Part II « The National Space Society of Phoenix

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