APOD

APOD brings us...

Approaching the nucleus of comet Tempel 1 at ten kilometers per second, the Deep Impact probe's targeting camera recorded a truly dramatic series of images. Successive pictures improve in resolution and have been composited here at a scale of 5 meters per pixel -- including images taken within a few meters of the surface moments before the July 4th impact. Analyzing the resulting cloud of debris, researchers are directly exploring the makeup of a comet, a primordial chunk of solar system material. Described as a recipe for primordial soup, the list of Tempel 1's ingredients - tiny grains of silicates, iron compounds, complex hydrocarbons, and clay and carbonates thought to require liquid water to form - might be more appropriate for a cosmic souffle, as the nucleus is apparently porous and fluffy. Seen here, Tempel 1's nucleus is about five kilometers long, with the impact site between the two large craters near the bottom.

Very interesting how they put this synthetic image together; a good demonstration of the power of modern computers. This would have been impossible not so very long ago...

The science reports starting to trickle out show Tempel-1 being surprisingly fluffy; a collection of powder "snow" (made of an exotic chemical mix) and sand that is just barely held together by the weak gravity of the "snowball". Before the mission scientists had a range of expectations about the comet's composition, from solid rock to "wet snowball". Tempel-1 seems to be outside that entire range...

Click on the picture for a larger view.