Wednesday, September 07, 2005

Comets and Organic Molecules

Deep Impact collision ejected the stuff of life

Millions of kilograms of fine dust particles and water and a "surprisingly high" amount of organic molecules sprayed into space when NASA crashed its Deep Impact spacecraft into Comet 9P/Tempel 1 on 4 July 2005, reveal a trio of new studies.

The observations bolster theories that comets may have seeded Earth with the raw materials for life and suggest they may be sponge-like – rather than hardened – at their cores.

Observers estimate the impact released about 5 million kilograms of water from beneath the comet's surface and between two and five times as much dust. There was so much dust, in fact, that mission members have not been able to see the impact crater with the high-resolution camera on the mission's flyby spacecraft, about 500 km away.

But here is the interesting part:

The team estimates the impact blasted away a crater about 100 metres wide and up to 30 m deep. Crucially, organic molecules were among the material ejected. Neither the full range of molecules nor their abundances have been determined yet, but researchers say they have found a surprisingly high amount of methyl cyanide, a molecule seen in large quantities in another comet.

This supports theories that comets may have brought water and the building blocks of life to Earth, and the team hopes to eventually "identify all the species comets brought in abundance to early Earth", says A'Hearn.