'Vertical Structure' in Saturn's Rings., page 2

reply to post by Mogget

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I looked up Daphnis on Wiki and your right about its orbit being inclined to Saturn's rings, it has a slight inclination and eccentricity. This moon takes about 14 hr 15 min to complete one orbit in which time its inclination causes it to move up and down by about 17 km and eccentricity varies its distance from Saturn by about 9 km.

Originally posted by Mogget
Notice how the "ripples" in the ring structure are on the outside ahead of Daphnis, and on the inside trailing it? That is a perfect demonstration of gravity at work.

I don't understand how this demonstrates gravity at work though. I would expect the effects of Daphnis' gravity to radiate outward and not just in its orbital path. I haven't read much about the orbital period of Saturn's rings compared to its moons. I originally thought these moons like Daphnis moved through the rings clearing out a path thus making the gaps that we see but now I don't know.


[edit on 8/11/2009 by Devino]

The following link provides an explanation of the "waves" produced by the gravity of Daphnis....

blogs.discovermagazine.com...

As for the "stars" attached to my original post....I have never really paid any attention to them in the past (or those "flags" that people mention from time to time). In fact, I didn't notice the "stars" above my post until Exuberant1 mentioned them!


[edit on 12-8-2009 by Mogget]

reply to post by Mogget

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Thank you very much
I've looked in exactly the wrong places for the explanation...and it's expressed in a 'knuckle dragging' manner I can understand perfectly.

And you can clearly see the ripples it causes in the rings, too! To the left of Daphnis the waves are on the edge of the rings outside the Keeler Gap, and on the right they are on the inside of the Gap. This may seem weird — it threw me for a moment — but remember the rings are made of particles that are traveling at almost but not quite the same speed as the moon itself. The particles in the ring outside the moon’s orbit (farther from Saturn) move a bit slower, and inside the moon’s orbit (closer to Saturn) move a bit faster. So it’s like cars on a racetrack, catching up and passing each other. When Daphnis passes the outer edge particles it pulls on them, and as the particles on the inside edge pass Daphnis they get pulled too.

The combined motions are pretty complicated, but add together to produce the effect you see here. And what an effect: those ripples are big, from 0.5 to 1.5 kilometers (1/3 to 1 mile) high. Even then they’re dwarfed by the immensity of the rings, though, which only rams home the scale of these images.

Mogget's Link

reply to post by Mogget

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Yes, thank you Mogget. I have read about the orbital velocities of the rings decreasing with distance but I was still lost.

Is this image viewed from the southern hemisphere? The rings appear to be moving in a clockwise direction so I assumed this view must from down under.

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