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Pan's weird shape


cypher_00

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Cool. I was guessing that Saturn's gravity was squeezing these moons into these shapes but according to the wiki info of Atlas it actually is captured material that accumulates around the equator and the size is related to it's Roche lobe. Very interesting.

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9 minutes ago, rudi1291 said:

Pan´s gravity must be really low for that ridge to not collapse. Almost looks like a disk seperating the two halves...

From the "hydrostatic equilibrium" wiki page:

"According to the definition of planet adopted by the International Astronomical Union in 2006, one defining characteristic of planets and dwarf planets is that they are objects that have sufficient gravity to overcome their own rigidity and assume hydrostatic equilibrium."

"assume hydrostatic equilibrium" = "become a sphere"

Edited by p1t1o
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40 minutes ago, Steel said:

Wow, I don't exactly know why but I'm blown away by those images!

"Home, sweet home!"

P.S.
Btw, we have already "seen" hot Jupiters, and now this is a "frozen Saturn", with rings under snow.

Edited by kerbiloid
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2 hours ago, cypher_00 said:

Cool. I was guessing that Saturn's gravity was squeezing these moons into these shapes but according to the wiki info of Atlas it actually is captured material that accumulates around the equator and the size is related to it's Roche lobe. Very interesting.

That was what I suspected. The ridges are in the plane of the rings, right? And because it's equatorial on the moon, it's going to stay stable in that orientation.

How thin the ridge is I think demonstrates dramatically how thin the rings are. Less than a kilometre thick, I believe.

And yes, Pan and Atlas have very low gravity. KSP's Gilly is about 25 times stronger.

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Critical params of celestial body:

Mass ~= (strength / G) 3/2 / density2

Radius ~= (strength / G) 1/2 / density

  Ice Lunar ground Granite Iron
Density, kg/m3 1000 2500 2700 7800
Strength, Pa 3*106 3*107 1*108 1*109
         
Critical mass, kg 1*1019 3*1019 3*1020 1*1021
Critical radius, km 200 300 500 500

Max height of mountain / pit = 3 * strength / (density * gravity)
For the Earth ~11 km

Pan: diameter = 26 km, mass = 5*1015 kg.
gravity ~= 2*10-3 m/s2.
Max mountain height ~= 3 * 3 * 106 / (1000 * 2 * 10-3) = 4.5*106 m = 4500 km >> 13 km.

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On 11/3/2017 at 10:36 PM, insert_name said:

It's obviously a flying saucer. Wake up sheeple!

Lol jk

Funnily enough the first thing that went through my mind on seeing those images was "Hogland's going to have a field-day with these images".

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On 3/10/2017 at 2:00 PM, rudi1291 said:

Pan´s gravity must be really low for that ridge to not collapse. Almost looks like a disk seperating the two halves...

Well, it is really small.

 

I wonder whether its related to the ring on iapetus, a larger moon who also has a ring on the equator (this one  at least looks sorta equitorlial, judging by sun angle.)

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