A Gnarly New Theory About Saturn's Rings (theatlantic.com) 25
Saturn has quite the collection of moons, more than any other planet in the solar system. There's Enceladus, blanketed in ice, with a briny ocean beneath its surface. There's Iapetus, half of which is dusty and dark, and the other shiny and bright. There are Hyperion, a rocky oval that bears a striking resemblance to a sea sponge, and Pan, tiny and shaped just like a cheese ravioli. But one moon might be missing. From a report: According to a new study, Saturn once had yet another moon, about the same size as Iapetus, which is the third-largest satellite in Saturn's collection. The moon orbited the ringed planet for several billion years, minding its own business, doing moon things, until about 100 million to 200 million years ago, when other Saturnian moons started messing with it. The interactions between them pushed the unlucky moon closer to Saturn -- too close to remain intact. Gravity shredded it to bits.
Something remarkable might have come out of all this. While most of the moon debris fell into Saturn's atmosphere, some of the pieces hung back, whirling around the planet until they splintered further and flattened into a thin, delicate disk. This lost moon, the authors of the study say, is responsible for Saturn's trademark feature: the rings. These astronomers didn't set out to find a missing moon. They were trying to better understand why Saturn is the way it is now -- specifically, why the planet is tilted just so. "Planetary tilts are an interesting indicator of a planet's history," Zeeve Rogoszinski, an astronomer at the University of Maryland who was not involved in this recent work but who studies orbital dynamics, told me. Most of the planets in our solar system spin at an angle relative to the plane in which they orbit the sun. Earth's tilt, for example, is a result of the collision that scientists believe might have created our moon. Mars's tilt is chaotic, thanks to the influence of next-door neighbor Jupiter. Uranus likely got its dramatic lean after the planet was whacked with a massive rocky object a few billion years ago.
Something remarkable might have come out of all this. While most of the moon debris fell into Saturn's atmosphere, some of the pieces hung back, whirling around the planet until they splintered further and flattened into a thin, delicate disk. This lost moon, the authors of the study say, is responsible for Saturn's trademark feature: the rings. These astronomers didn't set out to find a missing moon. They were trying to better understand why Saturn is the way it is now -- specifically, why the planet is tilted just so. "Planetary tilts are an interesting indicator of a planet's history," Zeeve Rogoszinski, an astronomer at the University of Maryland who was not involved in this recent work but who studies orbital dynamics, told me. Most of the planets in our solar system spin at an angle relative to the plane in which they orbit the sun. Earth's tilt, for example, is a result of the collision that scientists believe might have created our moon. Mars's tilt is chaotic, thanks to the influence of next-door neighbor Jupiter. Uranus likely got its dramatic lean after the planet was whacked with a massive rocky object a few billion years ago.
New??? (Score:4)
Not gonna RTFA, but TFS is pessimal.
Raise your hand if you didn't read this "new" theory in elementary school.
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Yeah, this is something that I learned back in the 90s.
Differs from the accepted theory how? (Score:5, Insightful)
Not interested enough to dig down to the original article to see what's new here. I guess maybe it's the part about some chaotic gravitational interaction with other moons being what dropped the destroyed moon close enough to Saturn to be ripped apart.
Re:Differs from the accepted theory how? (Score:4, Informative)
Bingo!
I actually read TFA - THERE's 3 minutes I'll never get back - and the prime candidate for which other moon's interaction flung the one they've dubbed Chrysalis into a Roche-limit-crossing orbit of doom is Titan.
Go figure. Gravitational interaction with what is by far the largest of Saturn's moons was (according to this new hypothesis) responsible for the fatal perturbation of the much smaller moon that became the modern Saturnian rings. Who'd'a thunkit?
The hypothesis is an interesting one, based on an otherwise-unexplained glitch in the resonance of Saturn's rotation with that of Neptune. It appears to account for that mis-match rather neatly. Unfortunately, TFA is a blazing garbage heap, written in a breezy, smart-alec style that makes you want to bitch-slap its author [theatlantic.com]. Of course, the link to the press release [berkeley.edu] that's the source for the information (which is much better-written than TFA) is buried 3/4 of the way down the page. And the study from which THAT is drawn is locked behind a Science magazine paywall.
For shame, The Atlantic. For shame ...
(Posting anonymously only so as not to undo prior upmods in this thread.)
--
Check out my novel [amazon.com] ...
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Atlantic has been garbage for quite a long time now.
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Re:Differs from the accepted theory how? (Score:4, Informative)
The Roche limit is literally named for Édouard Roche and his theory of Saturn's rings being formed by a ripped apart moon (he named the moon Veritas) in the 19th century.
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I've seen a lot of stuff like this over the years where someone has some incredible new discovery that we learned about in elementary school in the 70s. I have no idea why this is considered some big new discovery.
Re: New??? (Score:5, Interesting)
The "rings as moon debris" theory has been around for decades. The recent Cassini mission provided additional data to back this up. So, "new evidence" or research. Not new theory.
Additionally, the rings may be quite young. Based on their rate of collecting dirty, dark space debris, which reduces their albedo, they may only be tens of millions of years old.
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There's another quote where Clarke dates the ring formation as around three million
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What I gather from the article is that there's a certain lack of resonance between Saturn and Neptune that was expected but isn't there, and that this moon was instrumental in maintaining it until Titan kicked its orbit out of place. Since it happened
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The article claims that the “standing theory” is that the rings are a leftover from the forming of the solar system. That is new to me and most readers here, as we all obviously thought that “splintered moon” was the prevailing theory.
I haven't heard that as a modern theory either. The solar system has been around too long to sustain a disk of debris based on the rate it is shrinking. This is just based on stuff I learned 25 years ago, and was common knowledge then. It really is a shocking claim by the author.
Thought that said "Sauron's Rings" (Score:2)
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Uhuhuhuhuh (Score:4, Funny)
Uranus likely got its dramatic lean after the planet was whacked with a massive rocky object a few billion years ago.
So Uranus is off-kilter ever since it took something huge and hard a long time ago?
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So Uranus is off-kilter ever since it took something huge and hard a long time ago?
We really need to change the name of that planet to end these jokes once and for all.
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To Urectum?
Re: Uhuhuhuhuh (Score:2)
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Yes. How about:
Urmother
Trebeck!
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Cassini Established Rings Almost Entirely H2O Ice (Score:3)
And if they are almost entirely water ice, that kind of shoot this theory down. Moons are made of rock, and if the rings were formed by a moon then the rings would be made of at least a high percentage (relatively) of rock. But they aren't. There have been discussions about this in the past. I'm not coming up with this idea, this is one of the arguments against the rings being made from a destroyed moon.
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Wow, that last sentence. (Score:2)
Can't wait to see what the last sentence conjurs up for people. Should be an entertaining afternoon.