Mystery of Saturn's Two-Faced Moon Solved |
Mystery of Saturn's Two-Faced Moon Solved |
![]()
Post
#1
|
|
![]() Member ![]() ![]() ![]() Group: Members Posts: 524 Joined: 24-November 04 From: Heraklion, GR. Member No.: 112 ![]() |
Carolyn Porco comments included in this space.com article :
http://www.space.com/scienceastronomy/0710...ni-iapetus.html |
|
|
![]() |
![]()
Post
#2
|
|
![]() Member ![]() ![]() ![]() Group: Members Posts: 809 Joined: 11-March 04 Member No.: 56 ![]() |
Iapetus doesn't need a huge differentiation in brightness to start with; it just needs any amount of differentiation that will preferentially and predictably distribute ice from one location to another, rather than randomly; so that sublimation events remove ice from a slightly darkened area (making it darker and warmer) and deposit it in a slightly brighter area (making it brighter and colder). The (ice-)rich regions get richer, and the (ice-)poor get poorer.
The "natural" state of Iapetus, unaffected by external forces, would be, I think, an overall icy globe, all-white at the poles, but with darker sun-facing ridges and crater floors in the lower latitudes, just as we see in the middle of Roncevaux Terra. Cassini Regio is then a deviation from this basic state, motivated by an external force. That force would have to be solid particles, I think; surely a gas (of what origin?) suspended in circumSaturnian space would quickly become far too diffuse to have any real effect? But a very thin dusting, not needing to do more than to turn the ice cover from white to off-white, if it covered enough area would be enough to start the ball rolling. My question is whether it was a one-time event (something that disintegrated near Iapetus, for instance, leaving the dusting) or a series of repeated events, possibly still going on. I imagine the latter is more probable. |
|
|
![]() ![]() |
![]() |
Lo-Fi Version | Time is now: 24th June 2024 - 10:09 AM |
RULES AND GUIDELINES Please read the Forum Rules and Guidelines before posting. IMAGE COPYRIGHT |
OPINIONS AND MODERATION Opinions expressed on UnmannedSpaceflight.com are those of the individual posters and do not necessarily reflect the opinions of UnmannedSpaceflight.com or The Planetary Society. The all-volunteer UnmannedSpaceflight.com moderation team is wholly independent of The Planetary Society. The Planetary Society has no influence over decisions made by the UnmannedSpaceflight.com moderators. |
SUPPORT THE FORUM Unmannedspaceflight.com is funded by the Planetary Society. Please consider supporting our work and many other projects by donating to the Society or becoming a member. |
![]() |