Smacked asteroid's debris trail more than 6,000 miles long

The asteroid that got smacked by a NASA spacecraft is being trailed by thousands of miles of debris, with scientists expecting the tail to get even longer and more dispersed.

The image shows an expanding, comet-like tail more than 6,000 miles (10,000 kilometers) long, consisting of dust and other material spewed from the impact crater.

This plume is accelerating away from the harmless asteroid, in large part, because of pressure on it from solar radiation, said Matthew Knight of the U.S. Naval Research Laboratory, who made the observation along with Lowell Observatory's Teddy Kareta using the Southern Astrophysical Research Telescope.