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.

[tasp]

I am having trouble seeing how the precipitating linear stalagmite idea could generate 2 perfectly (less subsequent cratering damage) symmetrical diverging attendant ridges . . . .

Having an equatorial ring 'synced' up to the highest pre-existing spot along the Iapetan equator for its' emplacement generates a structure very similar to what we see. Having the highest spot along the equator either penetrating the ring plane twice per revolution, or having an inclined feature in the ring encountering that same high spot while it sweeps out a ground track +/- a few degrees either side of the equator explains the attendant ridges nicely.

Watch the ground tack of the ISS on NASA TV. Imagine dropping something overboard (neglecting orbital velocity effects to make the point) every time the ISS is directly over a fixed point in the equator. When the ISS is passing N to S across the equator, object always lands along the ground track S of the equator, for the passes S to N across the equator, the item lands along the ground track to the N. You get 2 piles diverging (at a 55 degree angle to the equator in this example, rather than the few degrees as we see on Iapetus) away from the fixed point on the equator.

The 'off ramps' are the 'smoking gun' for the emplaced ring material idea, its' the only way to make such a structure without a bulldozer.


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(extend the < arms with your minds eye if you will, I have very limited CG skills )