URTH |
From: "Dan'l Danehy-Oakes" <ddanehy@siebel.com> Subject: RE: (whorl) moon information! Date: Wed, 9 Jan 2002 09:31:36 -0800 > All right, guys. Finally got some real information that is pretty cool. > At confluence, Green is 30,000 leagues away (every six years). At one > point, someone mentions that at the moment of their comment Green is > 80,000 leagues away. Ok here is the cool part: 30,000 leagues is 89,996 > miles; 80,000 leagues is 239,988 miles. The distance from the earth to > the moon on average is 239,000 miles! I think we have to rethink what a "league" is here then. I assume that Green must have _at least_ the mass of Lune/Luna, because it manages to hold on to an atmosphere thick enough for Urthian humans. (I don't have the figures available. If we were to put an atmosphere around the Moon, could it hold on to it? I don't know. But I'm quite sure nothing much smaller could.) But the problem is this. The tidal force is gravitational, which means that it increases or decreases as the square of the distance. If the Moon (or a body the size of the Moon) had a spiral orbit that came in as close as 90K miles, water tides would be immense and wouldn't be our biggest problem - we'd experience noticeable ground tides, i.e., earthquakes that would make the Richter scale pretty much meaningless. And if Green is bigger than the Moon, well --! Incidentally, and again I haven't done the math so I can't be sure, but I _believe_ the much-larger mass of Earth/Urth would produce tides that would pretty much rip the Moon/Lune apart at that distance and we'd wind up with a ring instead of a moon. If this is right, then "30K leagues" _has_ to be more than 90K miles for the Blue/Green system to work at all. --Blattid