Simulating a high-velocity comet collision with Earth, a team of scientists has shown that organic molecules hitchhiking aboard a comet could have survived such an impact and seeded life on this planet.
The results give credence to the theory that the raw materials for life came from space and were assembled on Earth into the ancestors of proteins and DNA.
"Our results suggest that the notion of organic compounds coming from outer space can't be ruled out because of the severity of the impact event," said research geologist Jennifer G. Blank of the Department of Earth and Planetary Science in the College of Letters & Science at the University of California, Berkeley.
Blank and her colleagues Randy Winans and Mike Ahrens of the Chemistry Division of Argonne National Laboratory, and engineer-mathematician Gregory Miller of the Applied Numerical Algorithms Group of Lawrence Berkeley National Laboratory, will report their preliminary findings on April 5 at the national meeting of the American Chemical Society in San Diego, Calif. The talk is part of an April 4-5 session on extraterrestrial organic chemistry organized by Blank and colleague Max P. Bernstein, a chemist in the Astrochemistry Laboratory at NASA Ames Research Center in California.
Blank's team shot a soda-can sized bullet into a nickel-sized metal target containing a teardrop of water mixed with amino acids, the building blocks of proteins. More than seventy varieties of amino acids have been found in meteorites - many the suspected cores of comets that smashed to earth - and are presumed to exist in interstellar dust clouds.
Not only did a good fraction of the amino acids survive the simulated comet collision, but many polymerized into chains of two, three and four amino acids, so-called peptides. Peptides with longer chains are called polypeptides, while even longer ones are called proteins.