On Sun, 2010-01-03 at 09:27 -0800, Alastair wrote: > Hansen seems to believe that Venus had oceans, but that is now seeming > unlikely. It is now thought that Earth's oceans were formed from > impacts from Main Asteroid Belt Comets. > http://www.solstation.com/stars/asteroid.htm > These are icy outer asteroids which had there orbits distorted by > Jupiter. As their orbits became more elliptical, they collided with > Earth, which protected Venus and kept it dry. The runaway state of > Venus's atmosphere must be due to CO2, not H2O!
A scale model might help to visualize. If the Earth is a peppercorn, then the Sun is a 20 cm ball about 26 meters away. Get a peppercorn and a ball, and make a scale model of the Earth/Sun system. If you please, you could also add Venus another peppercorn 19 meters from the Sun, and the Earth's Moon, a bit of gravel 2 cm away from the Earth. Now imagine that there are comets coming from the outer solar system, in the neighborhood of Jupiter, another 110 meters beyond the Earth. Just how many of these comets will the Earth prevent from hitting Venus? -- Phil Hays <[email protected]> -- You received this message because you are subscribed to the Google Groups Global Change ("globalchange") newsgroup. Global Change is a public, moderated venue for discussion of science, technology, economics and policy dimensions of global environmental change. Posts will be admitted to the list if and only if any moderator finds the submission to be constructive and/or interesting, on topic, and not gratuitously rude. To post to this group, send email to [email protected] To unsubscribe from this group, send email to [email protected] For more options, visit this group at http://groups.google.com/group/globalchange
