NEOWISE: A Solar System Safari     1 2 3 4 5 6 7 8 9 10 11 A Comet's Telltale Tail A Comet's Telltale Tail The fuzzier one on the left is a comet, and the one on the right is an asteroid. When comets travel toward the sun, ice and dust evaporate away, forming cocoon-like clouds and tails. NEOWISE scientists spot comets with their own eyes by looking for the tails. This comet has a faint tail pointing toward the upper right. › Larger image › Read more     Jet Propulsion Laboratory    California Institute of Technology Start slideshow