From Sciencedaily.comNASA scientists are on the trail of Iapetus' mysterious dark side, which seems to be home to a bizarre "runaway" process that is transporting vaporized water ice from the dark areas to the white areas of the Saturnian moon. This "thermal segregation" model may explain many details of the moon's strange and dramatically two-toned appearance, which have been revealed exquisitely in images collected during a recent close flyby of Iapetus by NASA's Cassini spacecraft. Infrared observations from the flyby confirm that the dark material is warm enough (approximately minus 230 degrees Fahrenheit or 127 Kelvin) for very slow release of water vapor from water ice, and this process is probably a major factor in determining the distinct brightness boundaries.
3 comments:
I think the ridge is more interesting, and perhaps even harder to explain
But be honest Shaun, when is the last time you heard of Thermal Segregation!? Yes, the ridges are interesting, but a force that is pulling water vapor out of the ice at temps. below -200f? I am having trouble even conceptualizing this method. Every time I can recall having high concentrations of water vapor in the air, it would precipitate out at temps. well above -30 and that is at 1 atmosphere! I would have expected water to have boiled away long ago at substantially lower pressures.
Fair call :-)
I'd say that's two mysteries and counting.
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