Re: Small Comets source of earth's ocean

Hal Finney (
Sun, 24 Aug 1997 10:20:18 -0700

Mark Grant writes:
> Interestingly, I was watching a documentary about Jupiter recently where
> Gene Shoemaker (I think) was claiming that without a large gas giant in
> the system to 'hoover up' comets events like the dinosaur extinction would
> be so common that sentient life could not have evolved on Earth. If true,
> this could be another reason why life seems so rare in the universe.

BTW, for those who have not heard, Gene Shoemaker died this summer, in
an auto accident while doing field work in Australia. Shoemaker was a
well known and articulate astronomer/geologist/planetary scientist, most
famous for discovering comet Shoemaker-Levy, which crashed spectacularly
into Jupiter in 1994. He had made his mark earlier by establishing the
extraterrestrial origin of Meteor Crater, near Winslow, Arizona.

My wife took an intro geology class from Shoemaker when she was in college,
and he had always been one of her favorite instructors.