SPECIAL DELIVERY:

How comets may have 'seeded' life on Earth: A new look at a comet's core could reveal its role in our planet's early history (Peter N. Spotts, 9/08/05, The Christian Science Monitor)

Some scientists have long held the notion that comets delivered many of the chemical building blocks of organic life. NASA's Deep Impact mission to comet Tempel 1 has substantially strengthened their case.

This week, at a meeting in London and in results published in Thursday's edition of Science Express, Deep Impact scientists say they have found high levels of organic chemicals beneath the surface of Tempel 1's core. [...]

One surprise: The team has detected an unexpectedly high concentration of methyl cyanide. Biologists say methyl cyanide is a key player in reactions that form DNA.

"If methyl cyanide is a particularly abundant component, it would suggest that comets could have delivered an abundance of these highly reactive compounds to the early Earth," notes Tom McCollom, a researcher at the University of Colorado at Boulder's Laboratory of Atmospheric and Space Physics.