Tuesday, December 26, 2006
Comet Wild2 Data Causes Rethink of the Origin of Life
Results from the Stardust mission that returned last January 2006 to Earth with tiny particles from a July 2004 rendezvous with Comet Wild2 now has scientists rethinking the idea of the origin of life itself no less. The early solar system was shaken and stirred far more than astronomers ever thought, analysis of dust collected from a comet reveals. Comets may have brought exotic ingredients to the primordial stew that formed life on Earth.
The microscopic particles of dust from the tail of a comet collected from the Stardust spacecraft encounter have been analyzed by a one-of-a-kind atomic-resolution electron microscope and a team of 200 scientists. The group have been given a unique and unprecedented look at the building blocks of life. The samples contain clues to how the sun and planets formed from a giant gaseous cloud more than 4.6 billion years ago.
The most significant scientific surprise has been that Comet Wild2 contained a mineral called osbornite that forms at extremely high temperatures - nearly 5,000 degrees - and must have come from near the sun. The finding suggests the solar system couldn't have formed as was previously thought, from a slowly inward condensing cloud known as a solar nebula. Because the comet formed near the cold outer edges of the solar system, there must have been a great deal of mixing in the cloud. Material wasn't moving only inward; some was moving outward in a more dynamic solar formation process than previously suggested in theory.
Organic materials have also been found in the microscopic dust particles, older than the solar system, could reveal clues about the origin of life and whether it exists elsewhere in the universe. Because there was some sort of mechanism that spread matter from the inner solar system to the outermost area where comets were formed, the same stuff must have been sprinkled on all the other comets and planets in the solar system.