Elliptical Orbits

~~Shahin.Omar~~ · Nov6-09, 02:41 AM

Why revolving bodies have their orbits elliptical and not perfectly circular (please correct me if I am wrong)?

**A.T.** · Nov6-09, 03:21 AM

Originally Posted by Shahin.Omar

Why revolving bodies have their orbits elliptical and not perfectly circular (please correct me if I am wrong)?

Is there anything in nature that is perfectly circular? Perfect circles exist in math only.

**Vanadium 50** · Nov6-09, 03:50 AM

Because ellipses (technically, conic sections) are the trajectories of particles in a 1/r potential. If gravity had a different relation of force vs. distance, there would be different shaped orbits.

~~Shahin.Omar~~ · Nov6-09, 03:58 AM

Originally Posted by Vanadium 50

Because ellipses (technically, conic sections) are the trajectories of particles in a 1/r potential. If gravity had a different relation of force vs. distance, there would be different shaped orbits.

Just for a comparison, and I actually wonder about it: Celestial bodies revolve around other objects due to gravity, does the same apply to Saturn's rings too (or is it just like Saturn's atmosphere)?

I was looking for an example for a circular orbit. Saturn's rings are a set of large number of bodies and they together form a perfect circular orbit.

**mikelepore** · Nov6-09, 04:10 AM

If a satellite were in a circular orbit, but then it gets knocked by a meteoroid so that the direction of its tangential velocity is no longer exactly perpendicular to the direction of the gravitational force, that would make the orbit become elliptical.

**A.T.** · Nov6-09, 04:25 AM

Originally Posted by Shahin.Omar

Saturn's rings are a set of large number of bodies and they together form a perfect circular orbit.

They don't have one orbit, just individual orbits which are not perfect circles. The average of the individual orbit is closer to the circle but not a perfect circle either.

~~Shahin.Omar~~ · Nov6-09, 04:27 AM

Originally Posted by A.T.

They don't have one orbit, just individual orbits which are not perfect circles. The average of the individual orbit is closer to the circle but not a perfect circle either.

Thanks for the information, and is gravity responsible for their revolution as it is for the revolution of other celestial bodies?