I, for one, had/have no more belief that life came to Earth from comets than I do babies are brought by storks, but if one did/has, new research says you might have to drop that idea.
“Deteriorated DNA from microbes, frozen for millions of years in the Antarctic ice, shows that organisms could not have survived the bombardment of cosmic radiation during deep space travel from outside the solar system, said Paul Falkowski, a Rutgers biologist and oceanographer.”
“"It's almost an impossibility for comets to seed other planets with life after they've been in space for millions of years," Falkowski said.”
*Notice the word “almost” is used. Is this due to the idea of “no absolutes” or to leave an out incase they one day find life hitching a ride on the back of a comet?
“The Rutgers study refutes at least part of the "panspermia hypothesis" -- a theory from the Greeks, and popular among many scientists since the 19th century -- that microorganisms and biochemicals were carried to the planet by comets, meteors and asteroids.”