http://joshuacolwell.com/blog/index.php/2006/accreting-moons-in-saturns-rings/ Science, astronomy, politics, movies, and various minutiae. Tue, 13 Mar 2012 23:50:00 +0000 hourly 1 http://wordpress.org/?v=3.3.2 http://joshuacolwell.com/blog/index.php/2006/accreting-moons-in-saturns-rings/comment-page-1/#comment-485 JC Sat, 16 Dec 2006 06:17:30 +0000 http://joshuacolwell.com/blog/?p=121#comment-485 In answer to the first question: no. In answer to the second question: a qualified yes. It's not that the moons' densities themselves help provide reservoirs for moons, it's that they indicate that moons are in fact forming in Saturn's rings. The pre-Cassini view was that there was a one-way collisional cascade, and any moons in the rings were the leftover fragments from a disruption and there is no going back. We now see that the moons are rubble piles, and their growth may be fundamentally limited by external disruption rather than tidal forces (assuming that over long times there could be cold sintering and compaction of the individual pieces to form a more coherent and tidally resistant moonlet). Thus, the rings can be recycled rather than just the eroded fragments of one or two original precursor moons. In answer to the first question: no. In answer to the second question: a qualified yes. It’s not that the moons’ densities themselves help provide reservoirs for moons, it’s that they indicate that moons are in fact forming in Saturn’s rings. The pre-Cassini view was that there was a one-way collisional cascade, and any moons in the rings were the leftover fragments from a disruption and there is no going back. We now see that the moons are rubble piles, and their growth may be fundamentally limited by external disruption rather than tidal forces (assuming that over long times there could be cold sintering and compaction of the individual pieces to form a more coherent and tidally resistant moonlet). Thus, the rings can be recycled rather than just the eroded fragments of one or two original precursor moons.

]]> http://joshuacolwell.com/blog/index.php/2006/accreting-moons-in-saturns-rings/comment-page-1/#comment-483 John Weiss Sat, 16 Dec 2006 02:07:38 +0000 http://joshuacolwell.com/blog/?p=121#comment-483 I'm not sure that the work Carolyn presented suggests anything *new* about the age of the rings or Pan. Would the presence of a moon of a different density (factor of ~2) or shape in that location change the distription timescale significantly? Or did you mean that the short disruption timescale works well with the ease for re-accretion in that we can destroy and re-form small moons many times? I’m not sure that the work Carolyn presented suggests anything *new* about the age of the rings or Pan. Would the presence of a moon of a different density (factor of ~2) or shape in that location change the distription timescale significantly? Or did you mean that the short disruption timescale works well with the ease for re-accretion in that we can destroy and re-form small moons many times?

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