Pan's weird shape

[cypher_00]

Cassini has made close up pictures of Saturn's moon Pan:

https://www.nasa.gov/image-feature/jpl/cassini-reveals-strange-shape-of-saturns-moon-pan

It sure is weird looking with that ridge..

[Kryten]

The only other ring moon we've got good pictures of, Atlas, also looks like that.

[cypher_00]

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.

[kerbiloid]

LBA2. Twinsun.

Spoiler

Now they should search for the 

Spoiler

Emerald Moon

 

[rudi1291]

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

[p1t1o]

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 March 10, 2017 by p1t1o

[Steel]

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

[kerbiloid]

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 March 10, 2017 by kerbiloid

[cantab]

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.

[kerbiloid]

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.

[JetJaguar]

Interesting.  I'm making a planet right now that happens to have rings, and I was thinking to add a shepherd moon in a gap between them.  If I do, I'll try to make it a lenticular moon like this.

[cypher_00]

Iapetus which is also imaged by Cassini has a ridge but it's not really clear what caused that one..

https://en.wikipedia.org/wiki/Iapetus_(moon)

Saturn sure is a interesting system.

[Mitchz95]

And I thought Hyperion was bizarre!

[cypher_00]

Hah Hyperion looks like a teenager with Acne

[Atlas2342]

On 10/03/2017 at 8:47 PM, Kryten said:

The only other ring moon we've got good pictures of, Atlas, also looks like that.

That's me! 

[insert_name]

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

Lol jk

[Tyko]

One of Saturn’s Moons is Making Astronomers Hungry

New images of the tiny moon are drawing comparisons to a ravioli, empanadas, walnuts, hamburgers…nom, nom, nom

http://www.smithsonianmag.com/smart-news/saturns-moon-pan-making-astronomers-hungry-180962488/

 

[DerpzGames]

Looks tasty.

[Vanamonde]

Thank you for bringing this up, @Tyko, but we already have a thread for it. Merged.

[Vahal]

15 hours ago, insert_name said:

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

Lol jk

That's no moon! 

[kerbiloid]

Looks like a rubbered ball in an old computer mouse after several months of usage.

[Wjolcz]

This is how baby saturns look like.

[pxi]

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".

[Newt]

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.)

[kerbiloid]

Two balls with a ring of dirt sticked along their perimeters in rotation plane.