comet /asteroid was a source of origin of life? A comet is a dirty icy snowball and much of the dirty materials are organic material formaldehyde, hydrogen and more complex substances. In cold interstellar molecular clouds gaseous species such as H2O2, CO, CO2, CH3OH, H2O and NH3 are believed to condense on to sub micron carbonaceous grain to form these icy mantes. By a combination of process that included gas grain, chemical reactions, ultraviolet photolysis and cosmic ray bombardment these components could meet further to produce small amount of complex organic compound. Icy planetismals that probably formed through successive aggregation and agglomeration of such ice-coated grain might have carried significant amount of pre-biotic organic molecules to this earth during its early history. But these organic substances must had been destroyed by the heat generated of impact as comet bombarded in the early earth? If these fragile compounds had some how survived, they could have provided the starting point for the chemical evolution that led to more complex molecules like amino acids, nucleic acids and ultimately giant molecule “The RNA or DNA’. So in that case there needed extra terrestrial source of organic compounds. Carl Sagon told that only small parts of comets flowing in the earth atmosphere would stay cool enough to preserve the organic chemicals. J.Mayo Greenberg was however in favoring of comet as source of compounds as origin of life in this planet the earth. According to Greenberg the Icy particles make up the comets. In his laboratory, he made icy particles that make up comets. To create them he condensed mixture of water vapor, methane, CO, and other gases present in the interstellar spaces on a glass plate cooled to~100K. The Icy was amorphous like a comet ice, having a disorderly molecular structure rather then crystalline one. Amorphous ice conducts heat more slowly then the crystalline ice. Greenberg found that when ice was deposited very slowly as it would be in the interstellar grains it’s thermal conductivity become slower and slower by a factors 10,000-100,000, because of lesser connectedness’ of water molecules that had accumulated slowly. The effect of this lower thermal conductivity might have to insulate the organic materials against the heat of a cometary’s impact. While the outer layer of grains were vaporized during the comet collision on earth atmosphere, the inner part might survived unscalled and floated gently on sea of earth. But one of the most mysterious feature of present day is the fact that ribose and deoxyribose sugar in RNA and DNA are all right handed while amino acids that make up proteins are all south. This is a puzzle because sugars and amino acids are chiral molecule i.e. they can exist in two different mirror image. But on earth they do not exist as chiral. No one could answer how this enantiomeric excess came about on earth. Comet /asteroid was a source of origin of life? A comet is a dirty icy snowball and much of the dirty materials are organic material formaldehyde, hydrogen and more complex substances. In cold interstellar molecular clouds gaseous species such as H2O2, CO, CO2, CH3OH, H2O and NH3 are believed to condense on to sub micron carbonaceous grain to form these icy mantes. By a combination of process that included gas grain, chemical reactions, ultraviolet photolysis and cosmic ray bombardment these components could meet further to produce small amount of complex organic compound. Icy planetismals that probably formed through successive aggregation and agglomeration of such ice-coated grain might have carried significant amount of pre-biotic organic molecules to this earth during its early history. But these organic substances must had been destroyed by the heat generated of impact as comet bombarded in the early earth? If these fragile compounds had some how survived, they could have provided the starting point for the chemical evolution that led to more complex molecules like amino acids, nucleic acids and ultimately giant molecule “The RNA or DNA’. So in that case there needed extra terrestrial source of organic compounds. Carl Sagon told that only small parts of comets flowing in the earth atmosphere would stay cool enough to preserve the organic chemicals. J.Mayo Greenberg was however in favoring of comet as source of compounds as origin of life in this planet the earth. According to Greenberg the Icy particles make up the comets. In his laboratory, he made icy particles that make up comets. To create them he condensed mixture of water vapor, methane, CO, and other gases present in the interstellar spaces on a glass plate cooled to~100K. The Icy was amorphous like a comet ice, having a disorderly molecular structure rather then crystalline one. Amorphous ice conducts heat more slowly then the crystalline ice. Greenberg found that when ice was deposited very slowly as it would be in the interstellar grains it’s thermal conductivity become slower and slower by a factors 10,000-100,000, because of lesser connectedness’ of water molecules that had accumulated slowly. The effect of this lower thermal conductivity might have to insulate the organic materials against the heat of a cometary’s impact. While the outer layer of grains were vaporized during the comet collision on earth atmosphere, the inner part might survived unscalled and floated gently on sea of earth. But one of the most mysterious feature of present day is the fact that ribose and deoxyribose sugar in RNA and DNA are all right handed while amino acids that make up proteins are all south. This is a puzzle because sugars and amino acids are chiral molecule i.e. they can exist in two different mirror image. But on earth they do not exist as chiral. No one could answer how this enantiomeric excess came about on earth. See further
