Comets are crumbly
By terryh on Sep 14, 2005
Nature is reporting that analysis of the Deep Impact results has shown that the nucleus of a comet has very little cohesion. Its a very weakly bound aggregate of grains, held together mostly by gravity. So when you think of the "dirty snowball" model, don't think of a ball that's been moulded in your hand, think more of falling snow.