NASA Finds Bizarre X-Shaped Comet

The Hubble Space Telescope has captured an image of a bizarre X-shaped object with a comet-like streak of dust behind it, NASA announced yesterday. Scientists believe the images represent an extremely recent asteroid collision, with a small rock, perhaps 10-15 feet wide, colliding with a larger, roughly 400-foot-wide one. When they first sighted the image in January, researchers thought the collision had just occurred, but now they date it to early 2009.

Even that’s an amazing find. “If you look at the literature on 'recent' asteroid collisions, they tend to talk about things occurring in the past million years or so—that's recent,” one scientist tells the BBC. So with this event “we’re really catching it in the moment.” But the object is perplexing in several ways. Scientists can’t explain the X shape, or its behavior. “We expected to the debris field to expand dramatically, like shrapnel flying from a hand grenade,” said one astronomer. Instead it’s “expanding very slowly.” (More Hubble Space Telescope stories.)