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eppur_se_muova

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25. Most of the satellites, except for a few very small "shepherd moons", are very far out.

Mon Jan 19, 2015, 03:28 PM

Jan 2015

Since, within the Roche limit, tidal forces overwhelm the gravitational forces that might otherwise hold the satellite together, no satellite can gravitationally coalesce out of smaller particles within that limit. Indeed, almost all known planetary rings are located within their Roche limit, Saturn's E-Ring and Phoebe ring being notable exceptions. They could either be remnants from the planet's proto-planetary accretion disc that failed to coalesce into moonlets, or conversely have formed when a moon passed within its Roche limit and broke apart.

Roche limit

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What Huygens Saw On Titan - New Image Processing | Video [View all] Stephen Retired Jan 2015 OP

That was great! Thanks abakan Jan 2015 #1

Gosh, that's so cool... MrMickeysMom Jan 2015 #2

K/R Jack Rabbit Jan 2015 #3

Nice! Plucketeer Jan 2015 #4

That's great. Thanks and welcome to DU alfredo Jan 2015 #5

K&R BumRushDaShow Jan 2015 #6

Very cool! Enthusiast Jan 2015 #7

That's really interesting! 2naSalit Jan 2015 #8

Wow. SoapBox Jan 2015 #9

That was phenomenal edhopper Jan 2015 #10

Welcome to DU! And thanks for that facinating clip. FailureToCommunicate Jan 2015 #11

Very soon VWolf Jan 2015 #12

That was awesome! Stargazer09 Jan 2015 #13

I'm a space nerd too! Thanks for posting!!! LongTomH Jan 2015 #14

I don't know much about space... zanana1 Jan 2015 #15

Thanks for the post. ctsnowman Jan 2015 #16

Any shots of Jupiter from Titan's surface? Correction: Saturn leveymg Jan 2015 #17

That seems unlikely -- but Saturn should look impressive, if the haze doesn't obscure it. nt eppur_se_muova Jan 2015 #20

Oops. Glad someone was paying attention. leveymg Jan 2015 #23

Most of the satellites, except for a few very small "shepherd moons", are very far out. eppur_se_muova Jan 2015 #25

Interesting. Didn't realize Saturn was so much less dense than Jupiter. leveymg Jan 2015 #27

Saturn is the only planet that would float like a boat. :) nt eppur_se_muova Jan 2015 #28

It would make a cool pool toy. leveymg Jan 2015 #29

Yeah, this was an awesome post. Grateful am I. byronius Jan 2015 #18

Fascinating drm604 Jan 2015 #19

These are the kinds of worlds we will eventually be walking on.... Spitfire of ATJ Jan 2015 #21

Neato mosquito!! Manifestor_of_Light Jan 2015 #22

K&R! stonecutter357 Jan 2015 #24

awesome, thanks Duckhunter935 Jan 2015 #26

Really good video... polynomial Jan 2015 #30

Very good clip. Half-Century Man Jan 2015 #31