Comets and Biogenesis

More than 45 years ago, the chemist John Oro from the University of Houston, Texas, suggested that biomolecules or their precursors could have been formed in space and brought to our Earth by comets (Or6, 1961). Delsemme made similar suggestions at the ISSOL Conference in Mainz in 1983 (Delsemme, 1984). 

Which results led to the idea that comets are important in the evolution of life For more than ten years, some scientists have believed that life has (possibly) existed on Earth for more than 3.5 billion years recently, however, doubts have arisen as to whether this is really the case. It does seem clear that the heavy bombardment of the primeval Earth slowly started to decrease about 3.8 billion years ago. Many biogenesis researchers believe that a period of about 300 million years after the bombardment ceased would not have been long enough for life to evolve from inanimate systems. Thus the idea that comets (or perhaps even meteorites) played a role in the biogenesis process on Earth is quite appealing. Three possibilities are under discussion  

Life itself was brought to Earth from somewhere in the universe. 

The heavenly bodies which landed on Earth already had biomolecules on board . 

These bodies brought building blocks to Earth for the synthesis of biomolecules. 

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