While waiting for high-energy outbursts and cosmic explosions, NASA's Swift Gamma-ray Explorer satellite is monitoring Comet Lulin as it closes on Earth. For the first time, astronomers are seeing simultaneous ultraviolet and X-ray images of a comet.

Astronomers say a greenish backward-flying comet will make its way past Earth this month, as it takes its only trip toward the sun from the farthest edges of the solar system.

In 1996, a 7-year-old boy in China bent over the eyepiece of a small telescope and saw something that would change his life--a comet of flamboyant beauty, bright and puffy with an active tail.

A once-faint comet has made a sudden leap from obscurity to center stage. Comet 17P Holmes, now visible to northern hemisphere residents, increased its brightness by a factor of one million this week, going from magnitude 17 to 2.