This image provided by NASA shows comet Tempel 1 at the moment of impact with NASA's Deep Impact probe as it smashed into its surface.(AP photo)

    BEIJING, Sep. 8 (Xinhuanet)-- NASA's Deep Impact mission to comet Tempel 1 has supported the notion that comets seeded the barren infant planet of Earth with the chemical precursors of life.

    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.

    They have yet to identify all of the chemicals present in the material, which was ejected on July 4, when the comet collided with a projectile the Deep Impact spacecraft released.

    Scientists expect to identify all of the chemicals that comets brought in abundance to the early Earth in an effort to understand comets' roles in our planet's early history.

    One surprise is that the experts have detected an unexpectedly high concentration of methyl cyanide which 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.

    Methyl cyanide's abundance may also confirm that comets like Tempel 1 can open a window on conditions from which the sun and solar system formed some 4.6 billion years ago.

    NASA probe results imply that the nearly four-mile-wide comet nucleus is a loose ball of rubble.

    Moreover, when the impact struck, it burrowed into a layer of loosely bound, fine icy dust that is at least 30 feet deep.

    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." Enditem

(Agencies)