As the MER rovers blow out the candle on their one-year anniversary, they continue to make new discoveries on the Red Planet. How long they'll keep running is an open question, but NASA has several programs in the works for an encore.

Titan is a world where bits of muck continually fall out of the smoggy sky, blanketing the frozen surface like dark gooey snow. Squalls of methane rain periodically wash the surface clean, sweeping the organic gunk into rivers.

The Deep Impact spacecraft launched today and is now on its way to a rendezvous with comet Tempel 1. On July 4th, a specially designed impact spacecraft will detach from the mothership and crash head-on into the comet.

The Deep Impact mission will send a large copper projectile crashing into the surface of a comet at more than 20,000 miles per hour, creating a huge crater and revealing never before seen materials and the internal compostion and structure of a comet.

Looking at sun-like stars known to harbor planets, the Spitzer Space Telescope has found evidence of dusty rings similar to the Kuiper Belt in our own solar system. Beautiful new images from Hubble show how such systems might appear, looking from the outside in.

Most scientists believe a large meteorite impact in the Yucatan Peninsula led to the extinction of the dinosaurs 65 million years ago. But could a second, larger impact off the coast of India share the blame?

On Tuesday, October 26, the Cassini spacecraft will make its closest approach yet to Saturn's largest moon, Titan. Cassini will analyze the moon's thick atmosphere and take pictures of its mysterious surface.

The Chicxulub meteorite impact is largely credited with the extinction of 50 percent of the world's species, including the dinosaurs. But could there have been more than one meteorite impact 65 million years ago?

Planet-building is a violent, messy process. Observations made with the Spitzer Space Telescope indicate this process may last much longer than previously thought.

At least 50 percent of the world's species, including the dinosaurs, went extinct 65 million years ago. While most scientists now blame this catastrophe on a large meteorite impact, others wonder if there is more to the story.