An object discovered on 6 January in the Asteroid Belt appearing superficially like a comet, could turn out to be a rare collision of two asteroids.

The object, known as P/2010 A2, was discovered by the Lincoln Near Earth Asteroid Research (LINEAR) sky survey and occupies an orbit inside the main Asteroid Belt – not the typical location of comets, which swoop close to the Sun on long elliptical orbits. P/2010 A2 shares striking similarity to a comet, however, with a long tail of debris that appears to stream from a denser nucleus.

The tail of debris could instead be the tell-tale sign of an asteroid-asteroid collision, and would be the first time that such an event has unfolded in front of our eyes. Further supporting evidence for the collision theory comes from the observation of a nearby 200 metre-wide object that is moving in the same direction and with the same speed as the 'tail', and which may represent the largest fragment of one of the colliding asteroids.

The Asteroid Belt is littered with rocky bodies that show evidence for a violent history, but it is not certain how often major collisions take place. Over time, these collisions convert small asteroids into dust.

Continued observations, perhaps even with the Hubble Space Telescope, will shed more light on the ongoing event that is playing out in this region of the Asteroid Belt.