When Is an Asteroid Not an Asteroid? When It's a Chunk of a Comet.

If you think of them at all, you probably think of asteroids and comets as two distinct classes of objects. Asteroids are rocky and/or metallic, while comets are more icy and have fuzzy heads and long tails. But nature isn't so picky. Sometimes lines get blurred ... On Jan. 22 a small asteroid was seen in observations made by the Pan-STARRS survey telescope. The 'scope sweeps the sky every night, looking for (among other things) tiny specks of light that move among the background stars. These us...