X-Shaped Faux-Comet Likely Related to Prehistoric Dinosaur-Smasher

P/2010 A2, the mysterious object streaking through the solar system, appears to belong to the same family of asteroids that sent a huge rock our way 65 million years ago. Maybe it's trying to see whether Tyrannosaurs have re-evolved?

The item known as P/2010 A2 was first spotted on January 6, traveling through the main asteroid belt between Mars and Jupiter. For a while, no one could put a finger on its exact nature. Comet? Asteroid? The object's singular shape didn't help clarify matters. In recent images from the Hubble, P/2010 A2 appears as a glowing, airborne X with a ghostly vapor trail. It looks like nothing else in the sky.

By now, we're pretty sure that P/2010 A2 (also known by its cooler nickname, "Object X") is the result of two asteroids crashing into each other at speeds of about eleven thousand miles an hour. This collision probably happened sometime in the last few weeks. The contrails are bits of debris tumbling away into space. Ray Villard at Discovery posited that the crossed lines of the "X" might describe the trajectories of the original colliding bodies.

Astronomers suspect that P/2010 A2 originated in the Flora family of asteroids, a grouping in the inner main belt where asteroids are thought to bounce off each other with a fair amount of regularity. If this is the case, then Object X could be related to the K/T impactor — the asteroid that probably struck the Earth at the end of the Cretaceous Period, wiping out the dinosaurs and paving the way for endotherms to take over the world.

Because of its unique form, and because this is the first opportunity we've had to witness an asteroid mash-up firsthand, P/2010 A2 will probably remain an item of close study for some time. Therefore, we'll know about it relatively early if this body, like its Flora predecessor, shows any signs of moving in an Earthward direction (though there's absolutely no evidence to suggest this might happen). Attention, Object X: In case there was any confusion, we'd just like to clarify that "Jurassic Park" was a movie. No dinosaurs remain on Earth, as far as we know. So no need to come around and do a spot-check.

Image credit: NASA, ESA, David Jewitt (UCLA).