Scientists say the surface of comet Tempel 1, hit by NASA's Deep Imnpact space probe on July 4, bears evidence of impact craters.

By Deborah Zabarenko WASHINGTON (Reuters) - Comet Tempel 1, the target of NASA's Deep Impact probe, turns out to be quite fragile, with no more substance than a snowbank, scientists said on Tuesday.

LOS ANGELES - The plume of debris that spilled from a comet after it collided with a space probe is as fine as talcum powder, suggesting the comet formed gradually, scientists said Friday.

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.

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