Saturn's Rings May Be Very Old 125
Kristina from Science News writes "Combining computer simulations with data about the way starlight shines through Saturn's rings suggests the individual grains are big and thus could have been around a good 4 billion years, not the mere 10 million to 100 million previously suspected. What may have thrown earlier observations off is the chance that the grains aren't evenly distributed, but clump here and spread out there."
Re:That's not too surprising (Score:5, Informative)
You're mixing you're mythology. Saturn is Roman, Zeus is Greek :). Not that the joke wasn't funny, but it just looks odd ;).
Re:That's not too surprising (Score:3, Informative)
Greco-Roman gods are often mixed, but the Romans loved Greek culture and religion so much, they adopted all their deities! Jupiter == Zeus and Saturn == Cronos
So....since cron is named for Cronos, it actually does make sense that Saturn would hold on to things for a long time, just waiting for the right time to use them....
(Doesn't that just sound ominous?)
Re:if there that old... (Score:3, Informative)
Not likely, the ring particles have been bouncing off of each other for a long time. Saturn's rings are dynamically-speaking one of the oldest systems known (meaning each particle has made lots of orbits) and collisions occur on the scale of at *least* a few per orbit per particle in the B ring. (If clumping is occurring, it's even higher.) So the particles will probably have evolved from that alone. Plus, we don't know where the ring material came from. There's reason to think it was from an earlier moon which broke up, in which case a lot of the material may have been reprocessed in the moon's interior.
In other news... (Score:2, Informative)
Re:Frosty Post! (Score:2, Informative)
Re:That's not too surprising (Score:2, Informative)
"Cronos is the wily, youngest and most terrible of the children of Uranus, whom he hated. He castrated his father and became ruler of the universe, but was later overthrown by his own son Zeus."
http://www.maicar.com/GML/Cronos.html [maicar.com] in reality both were really bad
Re:Evenly distributed? (Score:4, Informative)
This will cause them to adjust their orbits to match. Well duh, right?
Actually, no. That isn't what happens, in spite of your intuition. The moon's response to the rings is largely to have a more rapid vertical motion than it would around just the planet. (This can be worked out for an embedded moon/planet in a disk using a Gaussian pillbox argument. It's a classic galactic dynamics question for undergrads, in fact.) There are more effects possible, depending on the relative masses and locations. For example, the moon can launch bending waves in the ring of material, which can then tug back on the moon. This can either pump up or damp down the moon's inclination. (Which isn't obvious and depends on a variety of parameters in the system.) The moon can also cause warps in the ring, but those tend to wind up pretty fast.
On the other hand, people *have* simulated rings. (Including myself, I might add.) You find that gravitational encounters between particles in the rings actually pump *up* the ring thickness. It's only with dissipative collisions that you get the ring to collapse down.
Your objections to the Cosmic Microwave Background are probably fodder for a different discussion, but it's difficult to see how that data shows evidence of a galactic collision, given the low energy involved (and the precise match to the predictions of the Big Bang). You should probably be worried that you're letting your desires for how the universe *should* be make you closed to what the data say it probably *is*. It's a very human response, but one that works contrary to good science.