Army Navy

Thursday, October 06, 2011

Earth's Water Delivered By Comets?

Comet Hartley 2
Well, why not?

Interesting report from BBC News Comet's water 'like that of Earth's oceans':







Given the amount of water on earth, the delivery schedule must have been a long one.


  1. When you have, as Carl Sagan actually didn't say, billions and billions of years, FEDEX (formerly Flying Tiger)rates of delivery aren't quite necessary.
    Pretty cool stuff. This is the sort of thing we covered in a planetary geology course I once took which also included such wild images as icebergs of rhyollite floating inlunar seas of molten basalt, hot ehough to glow blue.
    One of the guys who taught the course recently died, so to Dr. Mulberger, rest well, Marine.

  2. Anonymous9:38 AM

    A typical comet contains some 10 to the 13th power kg of water ice. How many comets would have to strike the Earth in order to account for the roughly 2 X 10 to the 21st power kg of water presently found on our planet? If this amount of water accumulated over a period of 0.5 billion years, how often would Earth be hit by a comet during that time?
    Divide the mass of the Earth's water by the mass of a typical comet: (2 X 10 to the 21st power kg) / (10 to the 13th power kg) = 2 X 10 to the 8th power comets.
    Divide this number by 5 X 10 to the 8th power years to get 0.4 comets hitting per year, or one comet every 2.5 years