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The waves and mountains of Saturn

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Arenamontanus Arenamontanus's picture
The waves and mountains of Saturn
http://io9.com/5678790/two+mile+high-mountains-discovered-in-saturns-rings http://www.ciclops.org/view_event/139/A_Story_of_Saturns_Rings Those images really bring home how strange the surroundings of Pan, the Hamilton cylinders and other habitats are. And why preservationists want to keep the rings as they are, rather than be used as a playground for megascale engineering.
Extropian
root root's picture
Re: The waves and mountains of Saturn
root@waves and mountains of Saturn [hr] I couldn't quite tell from the article what time scale the mountains change on. Are these standing waves such that you could build on them, or are they unstable so you could only build on large chunks of matter moving through the wave medium? It really brings a new meaning to poetics about the songs of the heavens, doesn't it? [EDIT] Where would I find the equations to model systems like this? And are there any Matlab scripts to be had for them?
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Arenamontanus Arenamontanus's picture
Re: The waves and mountains of Saturn
The mountains change over hours and days. They, like the rings, are composed of lots of ice fragments. Some are several meters across, others just snowballs or ice crystals. You cannot really build anything on them, but I guess you could park a small EVA vehicle on a big fragment and have a picnic. As for simulating, I think it can partially be done (the io9 article has a link near the end to a preprint doing simulations) but it is pretty complex. The main rings are due to resonance patterns with the Saturn moons, and then the new weirdness is partially due to "hydrodynamic" instabilities - very complex.
Extropian
root root's picture
Re: The waves and mountains of Saturn
root@The waves and mountains of Saturn [hr] As complex as Riemann Sphere maths? I'm apparently going to have to take a complex analysis math course next semester, and a naive understanding of the resonance issues here make put them right in the field of signal analysis. It's all just waves in the end, right? Riiiight. Maybe I should learn to do the math before I mouth off.
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Arenamontanus Arenamontanus's picture
Re: The waves and mountains of Saturn
The resonances are not that strange. Think of a ring particle orbiting. It will be perturbed by the weak gravity from a moon, occasionally dragged outwards, occasionally dragged inwards. In some places this averages out to zero: the particle and the moon have orbits that are so different that the total effect is random. But imagine that the particle has a period exactly half of the moon: every other time the particle is in a certain place the moon will be outside there too, perturbing it. The result is that the attraction adds up, and the particle goes somewhere else. The result is an empty gap in the ring wherever particles find themselves in a resonance with a moon. In other places you get a reverse effect that thickens the particles. Mathematically, you get gaps where the periods of ring particles is some simple integer ratio p/q of a moon period: the big Cassini division is due to the presence of Mimas. Some gaps are due to small moonlets inside the rings who have a 1/1 resonance (like Pan in the Encke gap). The same thing happens in the asteroid belt with Jupiter, but these gaps (the Kirkwood gaps) are less obvious since the asteroids have so eccentric orbits and with big inclinations. Saturn's ring particles move almost perfectly circularly in a plane.
Extropian