Author Topic: NASA - Cassini updates  (Read 162740 times)

Offline Star One

  • Senior Member
  • *****
  • Posts: 6334
  • UK
  • Liked: 1009
  • Likes Given: 146
Re: NASA - Cassini updates
« Reply #500 on: 03/14/2017 02:03 PM »
Enceladus' south pole is warm under the frost

https://phys.org/news/2017-03-enceladus-south-pole-frost.html

Offline Ben the Space Brit

  • Senior Member
  • *****
  • Posts: 6747
  • A spaceflight fan
  • London, UK
  • Liked: 426
  • Likes Given: 467
Re: NASA - Cassini updates
« Reply #501 on: 03/14/2017 02:23 PM »
Tidal heating from Saturn and Titan's gravitational fields?
"Oops! I left the silly thing in reverse!" - Duck Dodgers

~*~*~*~

The Space Shuttle Program - 1981-2011

The time for words has passed; The time has come to put up or shut up!
DON'T PROPAGANDISE, FLY!!!

Offline Star One

  • Senior Member
  • *****
  • Posts: 6334
  • UK
  • Liked: 1009
  • Likes Given: 146
Re: NASA - Cassini updates
« Reply #502 on: 03/14/2017 04:12 PM »
Tidal heating from Saturn and Titan's gravitational fields?

Sounds more than likely. As these hot spots vary in position over geological time by the sound of it, does that indicate there are variations in the moons orbits over the longer term?

Offline CuddlyRocket

Re: NASA - Cassini updates
« Reply #503 on: 03/14/2017 11:26 PM »
Tidal heating from Saturn and Titan's gravitational fields?

Sounds more than likely. As these hot spots vary in position over geological time by the sound of it, does that indicate there are variations in the moons orbits over the longer term?

More likely, perhaps, is that the axis of rotation shifts?

Offline TakeOff

  • Full Member
  • **
  • Posts: 295
  • Liked: 61
  • Likes Given: 84
Re: NASA - Cassini updates
« Reply #504 on: 03/15/2017 11:53 AM »
Tidal heating from Saturn and Titan's gravitational fields?
Isn't it more likely with tidal heating from Saturn's internal gravity concentrations (the effects of which can be seen in the ring structure) and its flatness and it rotating three times faster than Enceladus orbits? Saturn is 5,000 times more massive than Titan and five times closer to Enceladus.

I wonder how the heating occurs on a pole instead of at the equator, where tidal effects are the greatest on earth?

EDIT: Gaah, you wrote Saturn's AND Titan's gravity field, yes, I agree with that, I only saw titan when I posted this.
« Last Edit: 03/15/2017 11:56 AM by TakeOff »

Offline CuddlyRocket

Re: NASA - Cassini updates
« Reply #505 on: 03/16/2017 08:17 PM »
I wonder how the heating occurs on a pole instead of at the equator, where tidal effects are the greatest on earth?

It may depend on the inclination of the axis of rotation to the orbital plane. Tidal effects on Enceladus due to Saturn are greatest along the line connecting the centres of the two bodies.

Online ugordan

  • Senior Member
  • *****
  • Posts: 7258
    • My mainly Cassini image gallery
  • Liked: 1397
  • Likes Given: 289
Re: NASA - Cassini updates
« Reply #506 on: 03/16/2017 09:29 PM »
I wonder how the heating occurs on a pole instead of at the equator, where tidal effects are the greatest on earth?

I believe it might be a case of the region with the thinnest ice reorienting itself to one of the poles due to a tidal gradient on a non-spherical body. IIRC, the active south polar region is actually topographically slightly depressed compared to the rest of the ice shell on account of liquid water underneath having higher density than bulk ice.

It doesn't mean there's necessarily a mechanism that somehow concentrates the heating to the pole, just that the largest liquid pocket ended up there on account of either ice shell (if the ocean is really global, but deepest at the pole) or entire moon rotational drift.

Tags: