Solar System B

[Adi1008]

Answer (Click to Show Hidden Text)

[b]1.[/b] Could be a remnant of an older Iapetus in which it spun a lot faster, height suggests a max. rotation time of 17 hours. If Iapetus cooled fast enough to preserve the ridge but remained plastic long enough for the tides raised by Saturn to have slowed the rotation to its current tidally locked 79 days, Iapetus must have been heated by the radioactive decay of aluminium-26. This isotope to be abundant in early solar system 
[b]2.[/b]The ridge could be icy diapir If it had formed away from the position of the equator at the time, this hypothesis requires that the rotational axis would have been driven to its current position by the ridge. 
[b]3.[/b] Iapetus could have had a ring system during its formation due to its large Hill sphere, and that the equatorial ridge was then produced by collisional accretion of this ring. However, the ridge appears too solid to be the result of a collapsed ring. Also, recent images show tectonic faults running through the ridge, probably isn’t true. The bulge is in isostatic equilibrium typical for terrestrial mountains. It means that under the bulge there is material of low density (roots) 
[b]4.[/b] Iapetus could have had a moon that went inside the Roche limit and was torn apart by the tidal forces. The debris formed the ridge as it came crashing down. The initial impacts made a small indentations that went around the planet, but it was soon filled up.

Correct, your turn.

Explain the difference between a resonant and classical TNO. Give details on the orbits (eccentricities, semi-major axis, etc.) and examples.

[platinumfalcon]

What is the moon Iapetus mainly composed of?

It is actually known that only 20% of Iapetus is rock; the rest, as said above, is made of ice. Just a little fact

[goldfalcon]

nice

[platinumfalcon]

Oops, this thread is kind of dead. Let's revive!
Cassini-Huygens discovered these kinds of landforms at the poles of Titan, largest moon of Saturn.

[goldfalcon]

It found hydrocarbon lakes at the poles of the moon

[platinumfalcon]

@goldfalcon: Correct, your turn.
EDIT: Also, remember to hide your answers!

[goldfalcon]

Titan, the largest moon of Saturn is primarily composed of what material?
(Remember to hide your answer)

[platinumfalcon]

Answer (Click to Show Hidden Text)

Ice and rock; about half of each.

[VikP]

Since there hasn't been much activity for a while..... A quick one to kindle the fire
What is this and where is it found:


Bonus:
What mission studied these?

Added bonus:
What other large "landform"/(hint: "area") did this mission study?

[Panda Weasley]

This is a complete guess, but is it... (Click to Show Hidden Text)

Permafrost on Mars?