NASA finds comets dirty and fragile

According to the first detailed results from the NASA probe, the comet targeted by the Deep Impact comet-hunting mission on July 4 turns out to be a ‘‘snowy dirtball’’, made mostly of dust.

The outer surface ‘‘is unbelievably fragile,’’ Michael A’Hearn, an astronomy professor at the University of Maryland said, speaking of comet Tempel 1. ‘‘The comet is mostly empty, mostly porous.’’

One of the most interesting findings from the $333 million mission, published in this week’s issue of the journal Science, was the large number of organic molecules detected in the material blasted off the surface of the comet. The findings support the theory that comets seeded the barren infant planet of Earth with the chemical precursors of life, reported indianexpress.com