Studying their composition and behavior may lend clues about how our planets formed.
The Deep Impact collision, which was observed by more than 70 telescopes operated by teams the world over, was designed to mimic a meteorite smashing into a comet.
So far, scientists have learned from the collision that Tempel 1 originated from the area now occupied by Uranus and Neptune, and that it is a very fragile ball of dust and ice.
Only 6 percent of Tempel's surface is ice, and the rest is dust.
Willingale will present the his team's findings today at the National Astronomy Meeting in Leicester.
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