Aphs.219 net.space utcsrgv!utzoo!decvax!duke!phs!dennis Sun Feb 7 10:51:10 1982 Re: sri-unix.707: Horseshoe Orbits Nope -- it's not ignorance, it's just a point of view problem. Higher orbits are slower only in terms of angular velocity (speed relative to the surface). In linear velocity (yeah, orbits are ellipses, but that's the idea) higher orbits are faster. You need to accelerate from a low orbit to achieve a higher one. The ground speed is slower because the circumference grows quickly wrt speed and it has more distance to cover than it has extra speed to do it with. Thus, the two moons exchange kinetic energy (orbital speed) via gravitational attraction, and they BOTH (mutual and opposite) change orbits. The higher moon (the one caught up on) is decelerated and the lower moon is accelerated, causing them to exchange orbits. This will collapse eventually (tidal forces ALWAYS eat some of that kinetic energy), and either they will collide or just take up the same orbit; I suspect collision. ----------------------------------------------------------------- gopher://quux.org/ conversion by John Goerzen of http://communication.ucsd.edu/A-News/ This Usenet Oldnews Archive article may be copied and distributed freely, provided: 1. There is no money collected for the text(s) of the articles. 2. The following notice remains appended to each copy: The Usenet Oldnews Archive: Compilation Copyright (C) 1981, 1996 Bruce Jones, Henry Spencer, David Wiseman.