Re: Circular orbits, and other stuff

[Chuck Britton <britton@odie.ncssm.edu>]

I've heard that highly elliptical planetary systems are also scarce
(non-existent?) due to instabilities caused by orbit crossing. Precession
of an elliptical orbit will eventually cause a significant perturbation
that is usually destructive. There are lots of simulations available for
studying these things. Newton's Aquarium is one that comes to mind for the
Mac.

> > I have another question for those who teach astronomy. The first question
> > (how is solar spinning angular momentum transferred to the revolving planets
> > via magnetic forces?) was not answered. I assume it is not a simple topic.
>
> See below. It is not a simple topic, but it is sort of a nontopic.
>
> > This question has to do with the fact that planetary orbits are often
> > nearly circular. The same is true for numerous moons and rings. Kepler's
> > laws would not be violated if eccentricities of planetary orbits were
> > very large. Why are most orbits nearly circular?
>
> Tidal dissipation is strongest near periapse, and energy lost
> near periapse tends to circularize an orbit.
>
> > How do elipticities change when the spin of our Sun is being transferred to
> > planets?
>
> The Sun has negligible angular momentum, so the question is
> not really relevant to the solar system.
>
> Leigh


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Chuck Britton  					Education is what is left when
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North Carolina School of Science & Math		you learned in school.
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