Update:
December 14th 2006:
Comets As Toolkits For Jump-Starting Life
The idea that comets delivered the chemical "seeds" for life to the early Earth has been given a big boost. Scientists studying the tiny grains of
material recovered from Comet Wild-2 by Nasa's Stardust mission have found large, complex carbon-rich molecules.
"These results show that comets could have delivered nitrogen rich organic compounds to the early Earth where they would have been available for the origin of life," said Scott Sandford of NASA's Ames Research Center, Moffett Field, Calif.
http://stardust.jpl.nasa.gov/news/news109.html
"That's of interest because we know that in laboratory simulations where we irradiate ice analogues of types we know are out there, these same experiments produce a lot of organic compounds, including amino acids and a class of compounds called amphiphiles which
if you put them in water will spontaneously form a membrane so that they make little cellular-like structures."
http://news.bbc.co.uk/1/hi/sci/tech/5173992.stm
NASA Study Finds New Kind of Organics in Stardust Mission
Our studies of the comet dust show that the organics are very rich in oxygen and nitrogen," Sandford said. "The data are not incompatible with some of it being in the PAHs, but we still have a lot to learn in this area."
Although some of the other organics captured by the Stardust spacecraft look somewhat similar to the fairly stable organics found in meteorites, Sandford noted that many of the organic compounds appear to be very volatile.
One sample even showed an abundance of material containing alcohols.
Many scientists believe that comets are largely made of the original material from which our solar system formed and could contain pre-solar system, interstellar grains. According to scientists, continued analysis of these celestial specks may well yield important insights into the evolution of the sun, its planets and possibly, even the origin of life.
http://stardust.jpl.nasa.gov/news/news108.html
Stardust Findings Suggest Comets More Complex Than Thought
One of the major discoveries from the analysis of the comet samples was finding particles rich in organic matter. "Comets are believed to have brought water and organic matter to the early Earth, and it is important to understand the nature of these materials because they are necessary ingredients for the origin of life," said Lindsay Keller, NASA scientist at JSC and Stardust co-investigator. "One of the first analyses we obtained on the samples showed abundant hydrocarbons in many of the particles."
Subsequent analyses revealed that some of the organic matter formed in the cold cloud of dust and gas that was the precursor to the solar system.
http://stardust.jpl.nasa.gov/news/news110.html