Solar System B

[GoofyFoofer]

Welcome to the Solar System Question Marathon 2015!
I'll kick off!
What is the moon Iapetus mainly composed of?
[Hint: it causes Iapetus to have a low density]

[Unome]

Answer (Click to Show Hidden Text)

Ice

What main geological characteristic does Triton share with Io?

[Adi1008]

Answer (Click to Show Hidden Text)

Ice

What main geological characteristic does Triton share with Io?

Answer to Unome's Question (Click to Show Hidden Text)

This is an interesting question as both bodies in question are geologically active. [b]Both moons have volcanic activity, although they differ in nature as I'll briefly explain below.[/b] 

On Io, lava flows are silicate (i.e. molten rock), containing basalt silicate lavas with either ultramafic or mafic  compositions iirc. Silicate pyroclastics are thrown into the air and volcanoes on Io are scattered all over the planet. The term for this type of volcanism is [b]silicate volcanism[/b]. However, on Triton, it is much colder, as it is much farther away from the sun. The silicate volcanism phenomena are instead with [i]ice[/i]* . The term for this is [b]Cryovolcanism[/b]. On Triton, they seem to be concentrated near the southern (and likely northern iirc) pole

*usually just frozen/really cold stuff, like various clathrade hydrates, nitrogen gas, etc.

[Unome]

I mostly just asked that question to learn stuff

[Adi1008]

I mostly just asked that question to learn stuff

so, assuming I got that question right...

For the JUICE mission, explain how the 3GM instrument works and the type of data that can collected from it

[Ant-on-knee]

For the JUICE mission, explain how the 3GM instrument works and the type of data that can collected from it

The 3GM has a KA transponder and an ultra stable oscillator. It intends to measure the magnetic field of Ganymede and the extent of internal motions. I will also study the upper atmosphere of Jupiter and other Jovian moons.

[Adi1008]

For the JUICE mission, explain how the 3GM instrument works and the type of data that can collected from it

The 3GM has a KA transponder and an ultra stable oscillator. It intends to measure the magnetic field of Ganymede and the extent of internal motions. I will also study the upper atmosphere of Jupiter and other Jovian moons.

correct, your turn

[Ant-on-knee]

correct, your turn

What are the 4 theories for the formation of Iapetus's equatorial ridge?

[Adi1008]

correct, your turn

What are the 4 theories for the formation of Iapetus's equatorial ridge?

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.

[Ant-on-knee]

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.