New Moon Found In Saturn's G-Ring

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."

Comments

G-ring?

[Foo2rama]

I know there is a funny g ring comment in here somewhere!

Re:G-ring?

[LingNoi]

umm.. That's no moon it's a..

Re:G-ring?

[pete-classic]

The G-ring is a MYTH!

-Peter

Re:G-ring?

[RuBLed]

no, it's your mom, again...

Re:G-ring?

[Onyma]

You mean that little tiny Spot in the G area? Is it that much of a surprise it took these men so long to find it?

Re:G-ring?

[Loadmaster]

Through the smell-0-scope I would swear it's a planet of dead fish.

*ducks*

Re:G-ring?

[Feminist-Mom]

Seriously, I wonder if this is related to predictions from recent work in celestial mechanics, like by people like mathematicians Richard Montgomery. There is a revolution(no pun intended) in that area now.

Re:G-ring?

[nine-times]

I'd try to come up with a joke, but I don't even understand the story. It doesn't seem like a g-string can do much to hide a moon.

I guess whoever is doing the mooning has a really tiny butt?

Re:G-ring?

[Anonymous Coward]

To quote Pam:

"That's what she said! THAT'S WHAT SHE SAID!"

Re:G-ring?

[dotancohen]

You mean that little tiny Spot in the G area? Is it that much of a surprise it took these men so long to find it?

It's a third of a mile wide. Maybe they're not into BBW's.

Re:G-ring?

[MrKaos]

umm.. That's no moon it's a..

You may say 'That's no moon' but that's the biggest ring I've ever seen!

Re:G-ring?

[Architect_sasyr]

You're only saying that because you can't find it!

Re:G-ring?

[snsh]

Uranus has a bigger G-ring

Re:G-ring?

[gfxguy]

Luckily, in the future scientists will change the name of Uranus in order to avoid such infantile jokes.

We might as well start calling it Urectum now.

Re:G-ring?

[Jabbrwokk]

That's actually an O-Ring

And in an off-topic comment... WTF Slashdot? Ads for "Learn Biblical Hebrew online?" It's not April 1 yet.

Re:G-ring?

[Jabbrwokk]

If we did we could DDOS the living Xenu out of them.

Re:G-ring?

[Biff Stu]

At least they knew better then to search around Uranus.

A third of a mile makes it a moon?

[CronoCloud]

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."

Re:A third of a mile makes it a moon?

[russlar]

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.

Re:A third of a mile makes it a moon?

[Chris Burke]

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.

Re:A third of a mile makes it a moon?

[dotancohen]

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

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.

Re:A third of a mile makes it a moon?

[EMG at MU]

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

See:Natural Satellite. "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."

Re:A third of a mile makes it a moon?

[the phantom]

This may be a naive question, but what is wrong with using an arbitrary size or mass as part of the definition?

Re:A third of a mile makes it a moon?

[mhollis]

So, let me get this straight:

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

Re:A third of a mile makes it a moon?

[teh moges]

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:A third of a mile makes it a moon?

[dotancohen]

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

Re:A third of a mile makes it a moon?

[cbiltcliffe]

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.

Re:A third of a mile makes it a moon?

[Tubal-Cain]

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.

Re:A third of a mile makes it a moon?

[zippthorne]

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/

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

Re:A third of a mile makes it a moon?

[rnturn]

``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:A third of a mile makes it a moon?

[Tubal-Cain]

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.~

Re:A third of a mile makes it a moon?

[cbiltcliffe]

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.

Re:A third of a mile makes it a moon?

[SEE]

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, and everywhere.

Re:A third of a mile makes it a moon?

[lorelorn]

10% of the parent's mass as a threshhold would mean that our Moon is no longer a moon...

Re:A third of a mile makes it a moon?

[CheshireCatCO]

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.)

Re:A third of a mile makes it a moon?

[CheshireCatCO]

Except that we call some of the smaller moons (including this one) moonlets as well.

Re:A third of a mile makes it a moon?

[Tubal-Cain]

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)

Re:A third of a mile makes it a moon?

[CheshireCatCO]

In fact, it's called a "moonlet" in the original press-release: http://ciclops.org/view/5493/Tiny_Moonlet_Within_G_Ring_Arc

(Not sure why NASA's story linked in the summary doesn't use that title.)

Re:A third of a mile makes it a moon?

[ILuvRamen]

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?

Re:A third of a mile makes it a moon?

[cbiltcliffe]

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!!!"

Re:A third of a mile makes it a moon?

[CheshireCatCO]

Well, you'd leave out "rocky" since none of Saturn's moons that I can think of really meet that criterion.

Re:A third of a mile makes it a moon?

[jonadab]

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 that doesn't rely on arbitrary numbers. (For instance, you could say that if the center of mass of the combined system lays outside of either body they are companions, and otherwise the smaller object is a satellite of the larger. This has the consequence of making Pluto and Charon companion minor planets, but we've already taken the big step of demoting Pluto to minor-planet status in the first place.)

The harder question is where to draw the line between a small moon and a mere particle/rock/meteor/asteroid that happens to be in orbit around a much larger body. Personally, I'd vote for gravitationally-self-rounded, because I never felt that the asteroids around Mars were large enough to be proper moons anyway. This would also greatly simplify and reduce the moon counts for the gas giant planets. Smaller orbiting objects would still be natural satellites, of course; the definition would only apply to the word "moon". But the astronomical community has never reached any significant degree of consensus on this issue.

Re:A third of a mile makes it a moon?

[CheshireCatCO]

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.

Re:A third of a mile makes it a moon?

[mysticgoat]

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 primary)
  1. Mars: Demos, Phobos
  2. Jupiter: Io, Europa, Ganymede, Callisto, Almethea, Himalia, Lysethia
  3. Saturn: Mimas, Enceladus, Tethys, Dione, Rhea, Titan, Hyperion, Iapetus, Phoebe
  4. Uranus: Miranda, Ariel, Umbriel, Titania, Oberon
  5. Neptune: Triton, Nereid
• Other usefully named objects

The categorization is determined by these criteria:

1. Planets are big enough that they probably are not homogeneous but have different regions, some of which might be very interesting on their own (significant mineral resources, or unique, stable climates, etc). Any initial assessment of a solar system needs to include at least a cursory inspection of all the planets.
2. Double planets have significant gravitational effects on each other that need to be taken into account when working up an orbital approach, or with regard to choosing landing sites (to avoid unpleasantries like tidal slosh).
3. A moon is gravitationally bonded to a primary but is too small to have an appreciable affect on the primary. Other than collision avoidance, there is no need to consider moons when working up an orbital approach to the primary. An orbiting object is a moon if it is astrogationally useful (easily seen in a stable orbit such that a useful ephemeris could be constructed).
4. Other usefully named objects are a mix of moonlets, dwarf planets, comets, asteroids, and artifacts that are astrogationally useful.

   1. It might be useful for Earth's astronomers to begin thinking along these lines. We need a better taxonomy right now, before we start to get overwhelmed with exoplanet data. Adopting the kind of pragmatic taxonomy that a survey party from a distant place would likely use would be good for the short term; it could be replaced in a few dozen decades with something better when we have enough data to support an empirically derived "Periodic Table of the Planets". But let's drop the pretense that we could do such a table at this time.

Re:A third of a mile makes it a moon?

[dotancohen]

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.

Re:A third of a mile makes it a moon?

[Urkki]

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.

Re:A third of a mile makes it a moon?

[mysticgoat]

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 depth of 1,700 km. This is, however, a very parochial point of view.

From a system perspective, the Earth's core orbits around the barycenter once every 28 days, while any spot on the Earth's surface has a significant change in its angular relationship to the barycenter on an hourly basis due to the Earth's rotation. This results in significant tides, that are most easily seen in the constantly shifting boundaries between the atmosphere, hydrosphere and lithosphere along the coast lines where those three come together. The chaotic conditions at these boundaries literally keep stirring up a complex, highly reactive, chemical soup that contains portions of atmosphere, hydrosphere, and lithosphere mixing together in a manner that tends to maximize the reactive surface areas of each bubble or particle in the foamy, briney, brownish broth.

This life-sustaining (and possibly life-giving) situation is the signature feature of the Earth, and occurs precisely because the Earth is part of a double planet system whose barycenter resides a significant distance away from the Earth's core. If the Moon had no more influence on the Earth's orbit than any of the true moons of the other planets had on their primaries, there would be no tides and very much less intermixing of hydrosphere, atmosphere, and lithosphere, and probably much less life on the planet. The Earth is the way it is because it cannot be defined separately from the Moon: the two are married together in a very intimate way. This is a very different kind of relationship than any other moon has with its primary.

Argument for Pluto as a double or quintuple system stands unchanged. Taken together, that system has a planetary amount of mass, AND it is likely to have regional differences that could be interesting and would warrant investigation on an initial survey of the solar system. As opposed to Kuiper objects or other planetoids that do not appear to be very dynamic or particularly interesting (relative to other things that are available for study).

Re:A third of a mile makes it a moon?

[lorelorn]

You're right, sorry I was reading size rather than mass. The Moon is about 25% earth's diameter, but made of lighter material.

Re:A third of a mile makes it a moon?

[dotancohen]

You should present that argument to the IAU. Really.

http://www.iau.org/administration/secretariat/

Moon?

[crow]

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.

Re:Moon?

[dotancohen]

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.

Re:Moon?

[MichaelSmith]

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.

Re:Moon?

[dotancohen]

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.

Re:Moon?

[JasterBobaMereel]

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 definition (yet) so call it a moon (or not) as you like ...

Re:Moon?

[CheshireCatCO]

in the wrong direction

I assume you you mean that it spins in the wrong direction (like Venus and Uranus)? It definitely orbits in a prograde sense.

Re:Moon?

[dotancohen]

Thanks, I stand corrected!

Re:Moon?

[Urkki]

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.

Re:Moon?

[JasterBobaMereel]

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

Pathetic moon.

[schwillis]

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

Re:Pathetic moon.

[Jurily]

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.

Re:Pathetic moon.

[Adilor]

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

Re:Pathetic moon.

[Tubal-Cain]

Schools are not known for updating their textbooks very frequently. It could easily be many years before even half of them adjust.

Re:Pathetic moon.

[jonadab]

Yeah, that's no moon. (Wait for it...) It's a space station!

Scientist finds spot in G-Ring

[himthatwas]

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

Speaking of Pluto...

[msauve]

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?"

Re:Speaking of Pluto...

[Slur]

Oh, God. That's weird. What the hell is Goofy?

Re:Speaking of Pluto...

[TapeCutter]

Yes and if Pluto ever looks under Goofy's hat and finds his stash of supergoobers, Mickey is in deep shit. (god that makes me feel old!)

Re:Speaking of Pluto...

[Theoboley]

He's like Brian from Family Guy. A fully evolved humanoid-dog capable of speech lol

Re:Moon in Saturn's G-string?

[Tr3vin]

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

Slashdot - News for nerds.

Do I need to say more?

Re:Incredible

[DoofusOfDeath]

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

I.O.U

[x1n933k]

I.A.U

Re:Incredible

[Fluffeh]

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.

That's no moon!

[Anonymous Coward]

..wait, on second glance it is.

Johann Sebastian Bach

[mudshark]

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!"

Two Words

[rossdee]

Thuktun Flishithy

Her?

[Kupfernigk]

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.

Re:Her?

[dotancohen]

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.

The G Ring mystery

[Goodl]

Can easily be solved with string theory :-D

...and some fifteen years ago...

[SharpFang]

...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...

[Muad'Dave]

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