On a ring origin of the equatorial ridge of Iapetus Options

[Guest_AlexBlackwell_*]

Wing Ip just had an interesting Iapetus-related paper published in GRL.

[Rob Pinnegar]

I guess this idea probably originated with those images of Pan from a while back. If this proposed ring actually existed, it must have been very long-lived to last beyond the main era of heavy bombardment (either that or it was impact generated towards the end of said era).

The only thing that bothers me a bit about this idea is that, looking back at some of the images from the New Year's encounter a year and a half ago, there seem to be places in the ridge where the structure shows multiple parallel linear features -- which seems a bit more complex than this theory would seem to allow. However, given that we can't really see what those features are, they can't rule out the idea.

[tasp]

The only thing that bothers me a bit about this idea is that, looking back at some of the images from the New Year's encounter a year and a half ago, there seem to be places in the ridge where the structure shows multiple parallel linear features -- which seems a bit more complex than this theory would seem to allow. However, given that we can't really see what those features are, they can't rule out the idea.

It is the identical diverging attendant ridges that to me fairly shout externally caused.

Not counting the subsequent random cratering damage, the 'off ramps' are perfectly matched in slope, length, start and end points, and angle (north and south) to the main equatorial ridge structure.

Additionally, the 2 diverging attendants (btw, they are not parallel) describe segments of a great circle about Iapetus. Extend them all the way around Iapetus with your minds eye, and they cross the equator 180 degrees around and return to their starting point at the high end of the ridge. How could an internal geological process do something like that? It can't. All orbiting bodies ground tracks follow either the equator, or if inclined, great circle paths. We have a feature that shows three ground tracks that can only originate from an orbiting causation.


Handy way to get an idea of the scale of the ridge is to observe the very top of a vigorous thunderstorm anvil cloud in the US midwest. Such features can sometimes hit 20 km in height, similar to the 20 km height of the high end of the equatorial ridge.

An amazing feature.

Good place to send another pancam equipped rover . . . .