Has anyone read any theories on the origin of the equatorial ridge on Iapetus? This is one of the most interesting planetary features I've ever seen. On first look, it appears to be a compression feature, although I wouldn't exclude volcanism. The linearity and length (1/3 the satellite's circumference) is remarkable, as well as the altitude of the ridge peaks. The grade appears to be much steeper than Olympus Mons, which has really a quite gentle slope; this moon has some scenery indeed! Chesley Bonestell would be dancing with glee if he saw these photos, and I'd love to hear what Sir Arthur has to say. I can't wait for the next close approach (almost 2 years away darnit). I also wonder if it's related to the albedo difference between leading and following hemispheres. Current theories for that seem to be trending toward deposition, from sources either exterior to the moon or from within. Could it be that this body is actually composed of two formerly separate bodies of different compostion? Viva Cassini, a hearty "well-done" to the mission team! __________________________________ Do you Yahoo!? Meet the all-new My Yahoo! - Try it today! http://my.yahoo.com