What is inside a comet?

When comet Tempel 1 collides with a NASA space probe in the early morning hours of July 4, 2005, scientists at the Jet Propulsion Laboratory expect some holiday sizzle - a brilliant flash and a dramatic spray of debris.

This cosmic collision will create a crater exposing Tempel 1's interior. Like all comets, Tempel 1 consists of the frozen remains of material that formed the solar system. But what, precisely, is this stuff? How is it put together? Peter Schultz, crater expert, will help find out.

Schultz is a professor of geological sciences at Brown University and a leading expert in impact cratering, the science of what happens when a massive, fast-moving cosmic train slams into something. His work helps explain when and how comets, asteroids and other space travelers shaped the face of planets such as Earth and Mars, as well as the Moon and other satellites.

Schultz's expertise landed him a spot in the inner scientific circle for "Deep Impact," the joint space mission coordinated by the Jet Propulsion Lab and the University of Maryland. Schultz is one of 13 co-investigators overseeing the mission, which will provide a first-ever look inside a comet when scientists release an impactor into Tempel 1's path for a planned collision.

"This is heady stuff," Schultz said. "The ice inside comets has been in the deep freeze since the creation of the solar system. Now we are finally going to see what this stuff looks like and what it is made of. This is important information. Comets may have been the messengers that carried the ingredients of life to Earth