Did comets stir up earths brew?

Answer 1

Here is an account of two scientists who think so:

"NASA researchers: Comet
shower triggered life on Earth
comet

April 17, 1997
Web posted at: 7:00 p.m. EDT

From Correspondent Don Knapp

SAN FRANCISCO (CNN) -- It's one of the amazing, puzzling questions about the origin of life on Earth: What was the trigger that led to the formation of those primitive life forms that crawled out of the primordial soup many eons ago?

Two NASA researchers now say we may have some distant comet cousins of Hale-Bopp to thank for life itself.

Comets crashing into the Earth brought water, nitrogen and carbon dioxide that make up our atmosphere. But researchers Chris McKay and Bill Borucki have demonstrated that the crashing itself may have been a key event in the origin of organisms.
laser

McKay and Borucki created a vial of gas simulating the best guess of scientists as to the composition of the early atmosphere. They then mimicked a collision of a comet and Earth by aiming a laser blast at the primitive mix.

What they found was that the powerful shock waves from this "micro" blast created temperature and pressure changes that altered the molecular composition of the pseudo-atmosphere.

"Those new molecules, when mixed in with water, form amino acids. They're the start, the first step toward life," Borucki says."

More at the website below

Answer 2

Some people think a lot of our water is from comets.