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Unmanned Spaceflight.com _ Cassini general discussion and science results _ Science issue focused on Cassini's finale

Posted by: JRehling Jun 15 2019, 08:19 PM

There are multiple articles here about Cassini and Saturn, with particular focus on the rings.
https://science.sciencemag.org/content/364/6445

Two highlights: The mass of Saturn's rings is about 0.41 times that of Mimas and the age of the rings is estimated at 10 to 100 million years.

Posted by: Bjorn Jonsson Jun 17 2019, 10:47 PM

Lots of interesting results. A very interesting result is that the gravity measurements are not consistent with interior models relying on uniform rotation - deep differential rotation is required. The zonal wind flows are very deep and extend to a depth of ~9000 km. Interestingly, this is much deeper than Jupiter's winds (~3000 km).

Posted by: JRehling Jun 18 2019, 01:17 AM

One summary of Juno results included the supposition that Jupiter's magnetic field may be what dampens the deep winds – certainly a mechanism alien to terrestrial meteorology.

I just did the math on what the mass of Saturn's rings means in more relatable units: Given the area of the main rings, that mass corresponds to a solid disk 28 cm thick. Of course, we've known for centuries that that's not how their structure works. That would correspond to, say, rings 50 meters thick at about 200:1 empty space to solid matter. That would correspond to ring particles floating in a matrix with the space between particle centers about 6 times the particle diameter. At least on average, the gaps between the snowballs making up the rings would be too small for a person to nudge their way through without bumping into some. Of course, the density is known to be variable, but that paints a picture for me that's more vivid than I've had been before.

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