Comets - Possible Vehicles for Prebiotic Compounds
D.W. Hughes (2001), JBIS, 54, 169-179Refcode
It is beyond debate that life exists on Earth. It is also quite clear that comets not only contain large amounts of water, and considerable amounts of organic material, but also have orbits that enable them to scatter this material throughout the solar system. But are comets and life inexorably linked? Would life have broken out on Earth without cometary seeding? Do comets harbour microorganisms which they distribute throughout the universe? Or do comets bring to the surface of Earth nothing that we do not already have `down here' in ample quantities? This paper reviews the known physical and chemical characteristics of cometary nuclei and con- cludes that their extremely low temperatures and light-less existence probably make cometary nuclei extremely hostile laboratories for the complicated chemistry that converted basic organic building blocks into the com- plexity of early primitive life forms.
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