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Space Science

New Moon Found In Saturn's G-Ring 102

Posted by kdawson
from the ring-herder dept.
caffiend666 writes "Scientists have announced a new moon has been found hidden in the G Ring of Saturn. The discovery was announced Tuesday in a notice by the International Astronomical Union. This is one of over five dozen moons, and is only a third of a mile wide. No word yet on a name for the new moon; I vote Cowboy Neal."
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New Moon Found In Saturn's G-Ring

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  • G-ring? (Score:4, Informative)

    by Foo2rama (755806) on Tuesday March 03, 2009 @08:00PM (#27059007) Homepage Journal
    I know there is a funny g ring comment in here somewhere!
  • by CronoCloud (590650) <`moc.liamg' `ta' `noruaduolconorc'> on Tuesday March 03, 2009 @08:01PM (#27059011)

    Can you really call an object a third of a mile wide a "moon" rather than "just a rocky piece of junk that orbits Saturn, like a whole bunch of other stuff."

    • by russlar (1122455) on Tuesday March 03, 2009 @08:08PM (#27059089)

      Can you really call an object a third of a mile wide a "moon" rather than "just a rocky piece of junk that orbits Saturn, like a whole bunch of other stuff."

      The Astronomical community is feeling guilty about Pluto.

      • Isn't it strange how Goofy (the dog) is Mickey's friend, but Pluto (the dog) is his pet? In the animal cartoon world, doesn't that make Pluto a slave?

        And which did Iggy Pop mean when he sang "I wanna be your dog?"
      • by mhollis (727905)

        So, let me get this straight:

        The International Astronomical Union is made up of a bunch of size queens?!

      • You'd think the thing they'd feel guilty about is

        A celestial body that (a) is in orbit around the Sun, (b) has sufficient mass for its self-gravity to overcome rigid body forces so that it assumes a hydrostatic equilibrium (nearly round) shape, and (c) has cleared the neighbourhood around its orbit.

        http://www.iau.org/public_press/themes/pluto/ [iau.org]

        Which kinda rules out the entire field of extra-solar planets.

        • You'd think the thing they'd feel guilty about is

          A celestial body that (a) is in orbit around the Sun,

          I agree. They, of all people, should know to call it Sol.~

    • by Chris Burke (6130) on Tuesday March 03, 2009 @08:09PM (#27059109) Homepage

      Well since the majority of that "other stuff" is dust or ice crystals, some being maybe as large as a few meters, and the rings themselves are only about 10m thick, then yeah something a third of a mile wide stands out pretty significantly. They're sometimes called "moonlets" to denote the fact that they are, by moon standards, pretty small.

      • It's actually better than that, even. The G ring is made up of dust particles, so the size ratio is even more in favor of the new moonlet.

    • by dotancohen (1015143) on Tuesday March 03, 2009 @08:34PM (#27059363) Homepage

      Can you really call an object a third of a mile wide a "moon" rather than "just a rocky piece of junk that orbits Saturn, like a whole bunch of other stuff."

      There's about 150 of those in Saturn's system alone:
      http://en.wikipedia.org/wiki/Natural_satellite [wikipedia.org]

      However, nobody can find a good definition of a moon, just like the definition of the planet was hard to come by. The "cleared it's orbit" clause won't work for moons because they are the sources of the gas giant's rings (and gravitationally stabilize them), and the "gravitationally round" bit won't work either because it would eliminate lots of objects that we would like to call moons, such as the two rocks orbiting Mars. Come up with a good definition that does not rely on any arbitrary numbers (like size, mass, etc), and I'll submit it for approval.

      • This may be a naive question, but what is wrong with using an arbitrary size or mass as part of the definition?
        • Re: (Score:2, Troll)

          by teh moges (875080)
          Because the people that find objects just under that arbitrary size will be upset that their discovery isn't classed 'higher'.

          Pluto was one of the first big finds for American Astronomers, and many thing that its classification as a planet (and the continued uproar over its declassification) is just an American power play.
          • Re: (Score:3, Interesting)

            by rnturn (11092)

            ``Pluto was one of the first big finds for American Astronomers, and many thing that its classification as a planet (and the continued uproar over its declassification) is just an American power play.''

            Oh I think you're a little too anxious to blame on some jingoistic power play.

            Actually, we're just pissed off that that mnemonic phrase about ``Mister Victor'' we all learned in grade school is obsolete if Pluto isn't a planet.

        • Re: (Score:3, Interesting)

          by dotancohen (1015143)

          It doesn't scale to other systems. Jupiter has a moon larger in volume than Mercury, for instance.

          • Re: (Score:3, Interesting)

            by cbiltcliffe (186293)

            So you use a percentage size of the parent body.

            That way, Jupiter can have a moon the size of Mars, and Mercury still can't have a moon bigger than itself.

            • So you use a percentage size of the parent body.

              Good idea, but if the percentage is set at 10% of the parent's mass, you will still have people complaining that their discovery's 9.4% ratio didn't make the cut.

              • Well then, tell them after enough people dump on their insignificant discovery, it's mass will increase enough to put it over the hump to the next category.

                Then you tell them to stop bitching and grow up.

              • by lorelorn (869271)
                10% of the parent's mass as a threshhold would mean that our Moon is no longer a moon...
                • Wait, what? The Moon is 1/81 the mass of Earth. I'm pretty sure that a 10% figure would be an upper limit on moon mass since there are no moons in the solar system that I can think of that are bigger than that. (Charon is, as I recall, around 9% of Pluto's mass... although I might be remembering the stat a tiny bit wrong.)

                  • by lorelorn (869271)
                    You're right, sorry I was reading size rather than mass. The Moon is about 25% earth's diameter, but made of lighter material.
                • Now that would be ironic, considering that it's proper English name is The Moon. (I checked "Luna". Turns out to be the Latin name)
                  • But when we finally get a base set up there, then we call all legitimately say:

                    "That's no moon! That's a space station!!!"

            • by jonadab (583620)
              Right, the upper limit is not the big problem.

              Obviously, if you've got two things orbiting together, the larger one isn't going to be classed as a satellite of the smaller (although, under standard Newtonian physics, the relationship is actually mutual, even with a quite large disparity in size).

              There's some question about where to draw the line between twin-planets that aren't quite exactly the same size, versus a planet with a fairly large moon, but there are various ways to write a definition for that th
      • by SEE (7681)

        and the "gravitationally round" bit won't work either because it would eliminate lots of objects that we would like to call moons

        Meh. It's time to suck it up.

        The Solar System has eight planets (Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune), eighteen moons (Luna, Io, Europa, Ganymede, Callisto, Mimas, Enceladus, Tethys, Dione, Rhea, Titan, Iapetus, Miranda, Ariel, Umbriel, Titania, Oberon, and Triton), sixteen known dwarf planets (Hygiea, Vesta, Ceres, Pallas, Orcus, Pluto, Charon, Ixion, Varuna, (55636) 2002 TX300, Haumea, Quaoar, Makemake, (55565) 2002 AW197, Eris, and Sedna), and countless minor bodies here, there

        • It is past time to recognize that the prototypical example we naively chose for the "moon" category was an incorrect example. Earth's Moon is not a typical moon, as any passing astrogator from another sun would be quick to point out.

          A sensible alternate listing of solar system objects, as would be constructed by a visiting survey team, would look something like this:

          • Planets
            1. Mercury
            2. Venus
            3. Earth - Moon double planet
            4. Mars
            5. Jupiter
            6. Saturn
            7. Uranus
            8. Neptune
            9. Pluto - Charon double planet
          • Moons (grouped by prima
          • Earth - Moon double planet

            Our moon is called a moon because the gravitational center of the two objects is under the Earth's surface.

            Oh, and the Pluto - Charon system actually consists of four objects, not two, and the gravitational center is outside of them all. So it is a quintuple system, but certainly not a planet as it's orbit is littered with debris. The "cleared it's orbit" contingency is ingenious and it works.

            • Our moon is called a moon because the gravitational center of the two objects is under the Earth's surface.

              That is not an argument, it is merely a rationale for preserving an irrational attachment to an outmoded world view. It is also a very weak rationale. You can turn it around:

              The Earth - Moon system is a double planet whose barycenter is 73% of the distance between the Earth's core and its surface. That is deep in the mantle, but a very long way above the core. From the point of view of an observer on the Earth's surface, the barycenter sweeps under his feet once each day, moving at roughly 1,000 m/s, at a

          • by Urkki (668283)

            For extrasolar explorer, that classified Pluto-Charon as double planet, the list would be much longer, because there are a lot of Pluto and Charon like objects out there outside the orbit of Pluto.

            For any "outsider" definition of a planet, our solar system doesn't have nine planets. It has eight, or it has well over ten.

    • Yes, you can. Although you may have to apply a "let" suffix.

      See:Natural Satellite [wikipedia.org]. "There is no established lower limit on what should be considered a moon. Every body with an identified orbit, some as small as a kilometer across, has been identified as a moon, though objects a tenth that size within Saturn's rings, which have not been directly observed, have been called moonlets. Small asteroid moons, such as Dactyl, have also been called moonlets."

    • hey, they have their rules. Did you know if I pull my pants down while orbiting the planet, they'll classify me as a double moon?
  • by crow (16139)

    If something that small can be a moon, the Pluto should still be a planet. More seriously, how big does it have to be to be a moon? Eventually, we might be able to track much smaller rocks as distinct objects. There's probably a full range of sizes from dust particles up to this dwarf moon.

    • If something that small can be a moon, the Pluto should still be a planet.

      When Pluto clears it's orbit, it will be a planet.

      Size is not used to define objects for good reason. I agree that some definition of a moon must be formulated, however, as Saturn has over 150 of these little moonlets orbiting her, and new ones are discovered every so often.

      • If something that small can be a moon, the Pluto should still be a planet.

        When Pluto clears it's orbit, it will be a planet.

        Size is not used to define objects for good reason. I agree that some definition of a moon must be formulated, however, as Saturn has over 150 of these little moonlets orbiting her, and new ones are discovered every so often.

        I thought size was the issue with Pluto.

        • Finding other objects of Pluto's size was the catalyst for defining a planet. But Pluto orbits the sun outside of the solar plane, in the wrong direction, on a highly elliptical orbit that sometimes brings it closer to the sun than Neptune. It was obvious for a long time that Pluto differed from the other planets and should not be included. Finding other similar objects (which had been suspected for a long time) only cemented the deal.

      • Is there some convention that all planets are female? I had it that on the present system Venus, the Earth (Gaia) and the Moon are female, and the rest very definitely male. Moons of Jupiter are named for his - ahem - lady friends.
        • I think that one of Jupiter's moons is named after a male figure. I am not familiar with mythology so I really don't know which one, but I'm sure it's mentioned in Wikipedia somewhere.

    • Pluto is not a planet by the IAU definition a planet ... nothing to do with size ....

      Planet : is a celestial body that
      is in orbit around the Sun,
      has sufficient mass for its self-gravity to overcome rigid body forces so that it assumes a hydrostatic equilibrium (nearly round) shape
      has cleared the neighbourhood around its orbit.

      Neptune meets the first two but not the third so is a Dwarf Planet ....

      Moon/natural satellite does not have an IAU def

      • by Urkki (668283)

        If you mean that Neptune hasn't cleared it's orbit of Pluto, then yes it has. Neptune has locked Pluto into 3:2 gravitational resonance.

        Which IMHO is also a good common sense indication that Pluto is not a real planet, because it's orbit is controlled by Neptune.

        • I agree if Pluto is in orbital resonance with Neptune then
              a) Pluto is not a planet
              b) it is a satellite of Neptune

  • A third of a mile wide? They really need some higher standards for moon qualification.
    • by Jurily (900488)

      A third of a mile wide? They really need some higher standards for moon qualification.

      Let them have some fun with it. It's not like a categorization is actually meaningful. Besides, all the schools I've heard about still teach Pluto as a planet.

      • Schools are not known for updating their textbooks very frequently. It could easily be many years before even half of them adjust.
    • by Adilor (857925)
      It's all really about the proportion. Take the size of this object, and compare it to all the tiny little things floating around in those rings. It's significantly bigger, and therefore, could reasonably be called a moon.

      Yeah, forget the fact that it's a speck compared to Saturn itself, but whatever. Let them have their wonky classification "standards". :P
    • by jonadab (583620)
      Yeah, that's no moon. (Wait for it...) It's a space station!
  • It's a moon!
  • by himthatwas (318166) on Tuesday March 03, 2009 @08:24PM (#27059257) Homepage

    girlfriend is appreciative for the effort but politely suggests he keep looking.

  • How is this news, I thought that was the whole point of g-strings.

    • by Tr3vin (1220548)

      How is this news, I thought that was the whole point of g-strings.

      Slashdot - News for nerds.

      Do I need to say more?

  • Incredible (Score:1, Redundant)

    by DoofusOfDeath (636671)

    For years in the astronomical community there's been a debate about whether or not the G-Ring exists in planets.

    I think it's pretty obvious that all of our long, hard rockets should thrust towards the solar system's known G-Rings whenever possible. Anything less would be, well, selfish.

    • I'm impressed that I got modded "Redundant" when I had the very first post in the thread.

      • by Fluffeh (1273756)

        I'm impressed that I got modded "Redundant" when I had the very first post in the thread.

        Look, in my world, that clearly isn't as topsey turvy as your one is, the thread that is indeed redundant is at the bottom of the page, and in no way the "very first post". Sorry to burst your bubble kid, but this is the way the cookie crumbled.

  • by x1n933k (966581)
    I.A.U
  • by Anonymous Coward

    ..wait, on second glance it is.

  • Why?

    Wait for it...

    So when someone asks where the newly discovered moon is, you can answer: "Bach's there, in the G-Ring."

    Thanks! I'll be here all week! Tip your servers and avoid the crab Louie like black death!"
  • Thuktun Flishithy

  • Can easily be solved with string theory :-D
  • ...my teacher complained when on my astronomy essay I wrote "Saturn has countless moons, from which we have discovered about fifteen so far".

  • I say we call it "Thong", after the Greek goddess of G-[St]ring underwear.

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