Fireworks

How cool is this:

NASA's Deep Impact spacecraft completed a flawless journey to oblivion early today, slamming into an onrushing comet to vaporize itself in an Independence Day blaze of glory.

Scientists and engineers at NASA's Jet Propulsion Laboratory cheered as spectacular images taken by a second "fly-by" spacecraft positioned nearby confirmed that the "impactor" had scored a perfect bull's-eye, smacking into comet Tempel 1 at its lower edge at 1:52 a.m. EDT, spewing dust and ice in a column of debris that lit up the heavens

You know this would be cool even if it served no scientific perpose whatsoever. The good is that it does:

By assessing the shape and size of the crater and chemically analyzing the debris that belched from it, scientists hope to gain new insights into the composition of the solar system at the time of its formation 4.5 million years ago.

Comets, composed mostly of dust and ice, periodically migrate in from deep space, their outer layers burning away as they approach the sun. To get to the ancient material within, Deep Impact needed to punch through the boiling crust.