Bill Arnett, I am pretty sure that the outer moons of Jupiter have chaotic orbits. They are so far from Jupiter that their orbits are 3-body problems and more. I cannot tell you which moons are the most unpredictable. As you say, all orbits are chaotic over a long time period, but I am talking about practical matters, predicting the positions in the next 10 years or so. Dance of the Planets was one of the best programs for orbits, and they could not predict Pluto's position a century from now, if I remember correctly. This depends on the required accuracy, of course. They had orbits for all known moons, but could not give current positions for about half of the moons. Asteroids also have very chaotic orbits because of their proximity to Jupiter. Don't expect to predict asteroid positions accurately enough to identify them in a telescope if you don't have recent orbital elements. Some orbits are very stable and others change significantly. I do not have any references here at work, and would have to research the topic. As it stands, you can take my comment as anecdotal. -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]]On Behalf Of Bill Arnett Sent: Friday, October 27, 2000 2:51 PM To: Starry Night Discussion Subject: Re: [Starry Night] Saturn's new(ly discovered) moons on 00/10/27 2:13 PM, Gary Goodman at [EMAIL PROTECTED] wrote: > Concerning minor moons of Jupiter and Saturn > > The distant moons of these planets have chaotic orbits, i.e., they do not > follow Keplarian orbits because their motions are affected by both the > parent planet and the Sun (and other moons)... Are you sure about this? References? All the orbits in the solar system are chaotic on a time scale of billions of years but SNP doesn't go that far (which is probably the right choice). -- Bill Arnett [EMAIL PROTECTED] Emerald Hills, CA USA http://nineplanets.org/ -- To unsubscribe from this list or to subscribe to other SPACE.com Canada, Inc. mailing lists please visit, http://www.starrynight.com/cgi-local/lists.cgi -- To unsubscribe from this list or to subscribe to other SPACE.com Canada, Inc. mailing lists please visit, http://www.starrynight.com/cgi-local/lists.cgi
