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Titan, the largest moon of Saturn, is a fascinating and deeply alien world. Many bodies in space are, well, dead. No weather, no climate, no geology. Not Titan! Things are Happening on Titan, but none of the elements building the complexity and weather of this planet are the same as those on Earth.
I really enjoyed this video, and here are some exciting images. What happens when a river of methane carves "rock" of water-ice and organic sand?
@futurebird even a dead world can have geology if something collides with it. Or if it gets enough radiation.
@llewelly @futurebird tidal heating too (elliptical orbit around a gas giant that causes enough variability in the gravitational forces that the moon’s rock flexes enough to heat up)
@c0dec0dec0de @futurebird maybe this is a pointless theoretical distinction, but, can't you get tidal heating from a perfectly circular orbit as well? The "in" side of the orbiting world is going to be closer than the opposite side, and will get a stronger pull. If the world's rotation isn't tidally locked to its primary, the tidal bulges on each side will move through the rock as the world rotates, and cause tidal heating.
@llewelly @futurebird beyond my understanding, but it sounds plausible, might be lower magnitude?
@c0dec0dec0de @futurebird hm. I have always assumed the effect of rotating through the tidal bulges typically resulted in more heating than the elliptical orbit, but that may be a case of thinking about Earth as affected by solar tides (setting lunar tides aside for now), with a relatively low orbital eccentricity, and 365.24(somthing something) rotations per orbit.
@llewelly @c0dec0dec0de @futurebird
With a circular orbit; eventually rotation damps to being tidally locked and there is no more heating.
With an elliptical orbit; libration keeps tidal heating going even when the average rotation period is the same as the orbital period. This usually requires some third object (another moon, another planet, a star) to keep perturbing the orbit to stop the eccentricity from going to zero.
@llewelly @c0dec0dec0de @futurebird
Titan does have tidal heating, but it is small compared to sunlight.
So it matters for the subsurface water ocean; but not for the surface methane hydrology: https://www.science.org/doi/10.1126/sciadv.adl4741
What I also love about Titan is:
- It's cool name
- That it can be seen easily even with a small telescope. Saturn with its rings and Titan at its side is one of the coolest spots on the night sky.
