AP, Space.com, Science News, etc: A lost moon may have left behind the icy rings of Saturn
Monday, December 13th, 2010
A Southwest Research Institute scientist says he has figured out a scenario for the birth of Saturn’s rings. The planet, abetted by a disk of hydrogen gas, consumed a large moon billions of years ago, stripping it of its outer ice layers as its spiraled toward doom in the planet’s immense atmosphere.
That’s pretty dramatic in itself, but how about a crime angle too? The AP‘s Seth Borenstein spins the tale darkly as a “case of cosmic murder.”
I dunno that “murder!” is the first thing that crosses my mind when a shooting start flares in the night sky, but Borenstein keeps the CSI-mood going by declaring that Saturn stole its victim’s ice in the course of this murder most foul. He settles down fast after that, explaining the rudiments of the hypothesis, published on line Sunday by Nature, and comparing it to other scenarios proposed for the rings’ formation. He includes a note that what was originally a scattering of ice somehow released from the moon not only formed rings, but some of it reagglomerated into little moons.
How exactly a moon might be selectively stripped of its icy mantle, but not have its rocky innards spread wide too, is not explained very well in most news accounts, including the AP’s, but it presumably has to do with the Roche limit, cohesion…. I dunno, really. Stories below take a hack at it.
Other stories:
- Discovery News – Irene Klotz: Saturn’s Rings: Robbed From a Moon? ;
- Space.com – Mike Wall: Saturn’s Rings May By Remains of Ripped-Apart Moon ;
- ScienceNews – Alexandra Witze: Saturn’s rings explained ; She does the best at the explanation – first the moon gets heated and mooshed and segregated until water and ice are nearly all on the outside, and then tidal forces start dismanatling if from the outside in.
- AstronomyNow – Emily Baldwin : Saturn stripped icy moons to create rings ; Writer for this UK mag is an astronomer – and explains this well, too.
Grist for the Mill: SWRI Press Release ;
ps – We also have news circulating on the weird ridge of the Saturnian moon Iapetus. That’s really obscure, but really interesting too. Tomorrow, perhaps.
- Charlie Petit