Catch up on stories from the past week (and beyond) at the Slashdot story archive

 


Forgot your password?
Close
typodupeerror
×
Space Announcements Education Science

Two New Saturnian Moons 215

Posted by CowboyNeal from the heavenly-bodies dept.
Mixel writes "NASA's Cassini spacecraft, which has been orbiting saturn since the 30th of June has uncovered two previously unknown bodies. 'The moons are approximately 3 kilometers (2 miles) and 4 kilometers (2.5 miles) across -- smaller than the city of Boulder, Colorado.' The Huygens probe will be deployed to the large (bigger than Mercury!) yet mysterious moon, Titan, in December."
This discussion has been archived. No new comments can be posted.

Two New Saturnian Moons More

Two New Saturnian Moons

Comments Filter:

  • olbigatory quote (Score:5, Funny)

    by m1kesm1th ( 305697 ) on Monday August 16, 2004 @11:28PM (#9988031)
    Thats no moon...

    sorry, sorry... I'll get my quote, I mean coat.
  • Cool, a moon you can actually run all the way around in 20 minutes.

  • Millions of Moons (Score:5, Interesting)

    by Tablizer ( 95088 ) on Monday August 16, 2004 @11:34PM (#9988071) Journal
    Saturn actually has millions of moons if you count the boulders in the rings. If you don't count them, then where is the cut-off point? This debate has never been settled, and may require an arbitrary cut-off size to get a clean definition.
    • If we throw a trashbag out of the the ISS does that become a moon? What about a bolt that is dropped when repairing a sattelite?

      There must be some definition of a moon that includes some reasonable minimums -- like gravity or magnetic field.
    • The last time Saturn was visited, it had these "spokes" visible in the rings. Now, they're nowhere to be seen.

      This report: http://www.enterprisemission.com/_articles/05-27- 2 004_Interplanetary_Part_2/InterplanetaryDayAfter-P art2.htm [enterprisemission.com]

      Lists a large number of rather extraordinary changes that EVERY PLANET in the solar system has gone through in the last couple decades.

      Personally I find it rather alarming. Massive oxygen appearing on Venus? Io hotter than Mercury? Radical new weather patterns on Neptu

    • Re:Millions of Moons (Score:3, Interesting)

      by rokzy ( 687636 )
      there's a problem at the other end of the scale too: our moon, the Moon, is so big that the Earth-Moon system could/should be considered a double-planet system.

      there was a great article in the recent New Scientist about how the moon formed - a Mars-sized planet called Theia smashed into the Earth and the light rocks flung away formed the Moon.

      • Re:Millions of Moons (Score:5, Interesting)

        by Tablizer ( 95088 ) on Tuesday August 17, 2004 @12:51AM (#9988415) Journal
        there's a problem at the other end of the scale too: our moon, the Moon, is so big that the Earth-Moon system could/should be considered a double-planet system.

        I have heard a pretty good definition with the average center of orbit between the two bodies being inside the body of one of the pair. Our moon barely cuts it as a moon under this definition, but does, IIRC. However, such a definition does not work well with gasious planets since their boundary is fuzzy. But, it works pretty good with rocky bodies, at least fairly round ones.

    • Why arbitrary? Take a proposed, non-arbitrary, definition of a planet and apply it to moons:

      • Orbits a planet
      • Is rounded by its own gravity
      Add a condition of it having to be more massive than the rest of the mass in a similar orbit if you so desire. Anything else is simply a "natural satellite." Of course, now Mars won't have any moons and the original Doom story line would have to be modified to fit the correct terminology. Ah hell, geeks would never go for that!

  • Dammit! (Score:5, Funny)

    by lukewarmfusion ( 726141 ) on Monday August 16, 2004 @11:37PM (#9988082) Homepage Journal
    Why must everything be compared to Boulder, Colorado?
    • Being (presumably) composed of rock, this new moon could be considered a boulder in space. Thus, it is only logical to compare it to it's earthbound cousin.

    • Re:Dammit! (Score:4, Informative)

      by Compholio ( 770966 ) on Monday August 16, 2004 @11:41PM (#9988111)
      Maybe because the discovery was in Boulder?

      Cassini Imaging Central Laboratory for Operations
      Space Science Institute, Boulder, Colo.
      -- http://saturn.jpl.nasa.gov/news/press-releases-04/ 20040816-pr-a.cfm [nasa.gov]
    • Okay, so how many Libraries of Congress would that be?
    • Anybody ever been there? Boulder, Colorado I mean, not the moon...

      • Re:Dammit! (Score:3, Funny)

        by Fred_A ( 10934 )
        Wasn't there this rumor that Boulder, colorado was actually faked in a studio ?
      • > Anybody ever been there? Boulder, Colorado I mean, not the moon...

        I used to live in Boulder. It's a great town if you're a rich white Buddhist. Unfortunately, I only qualified on one out of the three...

    • Re:Dammit! (Score:3, Funny)

      by Dr. Cody ( 554864 )
      Why must everything be compared to Boulder, Colorado?

      It's all part of our quest to replace the metric system. You see, Boulder is a megaVWBug.
    • beats the cliche, ''bout the size of Rhode Island" one... But to run a quick conversion, there are 5 Boulders in a RH, and about 20 RIs in a Texas.

      And to further convert this new metric, there is a cubic shitload of Texas' in an Earth.
    • Maybe because moons are just really large boulders...

    • finally a sensible measurement system - "VBR" (Score:5, Funny)

      by jpellino ( 202698 ) on Tuesday August 17, 2004 @07:01AM (#9989556)
      we now have a third metric to add to the existing system of measuring everything in pop news stories in "volkswagens" and "rhodeislands" (1), we can now hit that middle mark, "boulders", though it's not so middle...

      the conversions for the VBR go something like this (2):

      beetle ('classic' at 160" x 60" = 9,600 sq in = 66.67 sq ft footprint
      boulder = 25 sq mi = 696,960,000 sq ft
      rhode island = 1,214 sq mi = 33,844,377,600 sq ft

      which means

      10,453,877 beetles in a boulder
      48.56 boulders in a rhodeisland
      507,640,282 beetles in a rhodeisland

      which would make a hellova traffic jam (3)

      (1) also haven't read the journals of irrepreoducible results / AIR for a while so this could all seem cribbed - sorry if so

      (2) (check my math, it's early still)

      (3) virtually no change to downtown newport in the summer however
    • smaller than the city of Boulder, Colorado.

      Yeah, but four times more exciting! (Yes, I've been to Boulder)

  • Are they really moons? (Score:5, Interesting)

    by Anti Frozt ( 655515 ) <{chris.buffett} {at} {gmail.com}> on Monday August 16, 2004 @11:38PM (#9988088)

    Where do we draw the line between classifying a stellar body as a moon or an asteroid? Do we simply base it on the fact that it's a piece of rock orbiting a planet or is there some other defining characteristic?

    Ceres, the largest asteroid in our solar system, has a diameter ~950 Km in length, much larger than many of the so-called moons we've discovered.

    • Re:Are they really moons? (Score:5, Insightful)

      by servognome ( 738846 ) on Monday August 16, 2004 @11:50PM (#9988147)
      Moons orbit planets, asteroids orbit the sun.
      There does need to be some cutoff at where something is considered a moon and where its just a rock going around a planet, otherwise all the stuff in Saturn's ring could be considered moons... hmm maybe I could name one "Servognome" and request a goverment grant of $50,000 to study the rock^H^H^H^H moon.
      I think all this classification stuff probably has to do with how scientists can get more grant money. Kinda how there are 6 great lakes [dencities.com]
    • The line between the two is what they orbit. A moon orbits a planet, an asteroid orbits the Sun.

      Of course, when whether we should just stop calling an object orbiting a planet a moon, and just call it a rock when it's past a certain minimum size, is up to the scientists.
    • Moons orbit other (non-solar) bodies. Ceres can't be a moon because it only orbits the Sun. Some asteroids have satellites (moons) themselves.

      There is no set cut-off point, but several miles seems to be considered moon-sized, while the larger chunks in Saturn's rings aren't big enough at a few hundred feet.
    • There's alot of debate on that, some people don't even think pluto should be considered a planet. A good way to classify it is: Planet - A really big rock with a sane orbit around a star Moon - A smaller rock orbiting a planet Comet - a rock with a highly ecentric orbit Asteroid - a tiny rock that isn't in perfect orbit with a planet, or is just floating around orbiting the sun or something. I guess the scientists like to say they've discovered moons, because discovering asteroids sounds much less cooler.

    • Re:Are they really moons? (Score:2, Interesting)

      by Conch ( 52381 )
      There is actually a limit uppwards. It's no longer a moon if the center of gravity for the planet and the moon are outside of the planet. In this astronomical sense is our moon actually not a moon but the earth and the moon make up a bi-planatery system.
      • Hooray! Mod parent up! Grandparent down too, if you've got another point to spare ...
      • The average center of orbit between the Earth and the Moon (bearing in mind that the Sun *does* orbit the earth, and all the other planets in our solar system, and probably, all planets, suns and objects anywhere in the universe, to a small degree) is very close to the center.

        Therefore, we can say the moon is the satellite. Even though it is only because Earth is bigger. I would do some kind of demonstration but the rubber sheets are being cleaned right now... ^H^H^H^H^H^H damn Shift-6,Shift-H no longer wo

  • very punny scientists (Score:2, Funny)

    by Anonymous Coward
    'smaller than boulder colorado'

    nyuk nyuk

  • Smaller than Boulder... (Score:5, Funny)

    by Black Parrot ( 19622 ) on Monday August 16, 2004 @11:43PM (#9988119)

    ...but bigger than Little Rock?

  • hurm (Score:4, Insightful)

    by ErikZ ( 55491 ) on Monday August 16, 2004 @11:48PM (#9988135)
    I'd say it's a moon when it's big enough to exert enough gravity to walk on, without worrying about being flung out into space.

    • Re:hurm (Score:3, Insightful)

      by Capt'n Hector ( 650760 )
      You might, but then you're being human-centric. Our definition of moon shouldn't depend on our size/weight. I'd say that if two or more bodies are obriting around each other, which in turn are orbiting around a stellar body, then the largest one is a planet, and the smaller one(s) is/are a moon.

      All of these objects must have a spherical shape, ie enough mass to have collapsed into a planetoid configuration.

      Using this defintion, I would call mars's "moons" "captured astroids" or "natural satellites", s

      • Re:hurm (Score:4, Funny)

        by nacturation ( 646836 ) <nacturation&gmail,com> on Tuesday August 17, 2004 @12:32AM (#9988331) Journal
        I'd say that if two or more bodies are obriting around each other, which in turn are orbiting around a stellar body, then the largest one is a planet, and the smaller one(s) is/are a moon.

        So according to your definition, Epsilon Lyrae [skyhound.com] with its pair of stars orbiting another pair of stars, one of those stars is a planet and the smaller star is a moon.
        • Fine, insert into the definition: if anything is undergoing sustained hydrogen fusion, it's a star. If it's undergoing deuterium fusion, it's a brown dwarf.

          PICKY!

      • That's interesting, but you haven't explained why being human-centric in this situcation is bad.

        Several people have asked (in a roundabout way) for something more definitive. I don't have the numbers, but the test would go something like this:

        If any unmodified* human, can achieve escape veolocity under it's own power**, then it's not a moon.

        I think this will actually be a good definition because it will help the people who will be working on the moon/asteroid.

        * Sans genetic or bionic modifications.
        ** If
      • One problem with this is that "orbiting" is not well defined. When you get right down to it every body in the universe exerts a tiny force on every other.

        Say there are two asteroids orbiting the sun whose orbits intersect every couple years, so that they perturb each other. Are they orbiting?

        If three asteroids, or ten, are all following a mutual chaotic orbit, does it make sense to call one of them a planet?

    • Now wait a second... (Score:3, Interesting)

      by rarose ( 36450 )
      What if the gravity is strong enough for a suicidally depressed person to walk on, but weak enough that a happy person with a little "bounce" in their walk goes flying off into orbit?

      Of course the thought of that would be enough to make any astronaut upset.... so... wait... I guess that won't be a problem.

    • Re:hurm (Score:4, Informative)

      by Spy Hunter ( 317220 ) on Tuesday August 17, 2004 @03:28AM (#9988865) Journal
      You made me curious; here's a page I found with a semi-rigorous calculation of the largest body which has an escape velocity small enough for a human to actually jump completely off of it. (I was going to do the calculation myself, but then I found this page) Link [aci.mta.ca]

      For those too lazy to read the link, the result is a meteor with a diameter of about 7 km would be required to increase the escape velocity enough that you couldn't jump off. This of course assumes a certain density for the meteor and also that you are an olympic high-jumper. Also, it assumes that you can apply the same jumping force on the meteor as on the earth, which probably isn't true as you couldn't get a good running start. But it's an interesting result nonetheless, and using your definition these "moons" probably wouldn't qualify. Certainly comfortable walking would be impossible.


      • Wow, it never occured to me to do a google search on something like this. It just goes to show, an original thought is very very rare.

        I really appreciate that you dug this up and posted the link. If I had mod points, you'd get them.

        And back to the point. 7km? I know I've only noticed one source of gravity in my life, but 7km is surprisingly small to me.
        • If you've never noticed any other source of gravity (from its effects of course, not directly) clearly you've never been near a very large body of water. Like an ocean.

  • Re-discovered? (Score:4, Interesting)

    by Mick Ohrberg ( 744441 ) <mick,ohrberg&gmail,com> on Monday August 16, 2004 @11:54PM (#9988167) Homepage Journal
    It seems like one (S/2004 S1) of the little worldlets may have been re-discovered since it may have been spotted when one of the Voyager probes passed Jupiter by in 1981, then christened S/1981 S14.

  • A couple of definitions (Score:5, Informative)

    by cy_a253 ( 713262 ) on Monday August 16, 2004 @11:57PM (#9988186)
    A satellite is any object that orbits a planet, regardless of mass.

    A moon is any natural object that orbits a planet, again regardless of mass. (so probes and debris don't qualify)

    A planet is an object massive enough to become spherical under its own gravitationnal field, that orbits a star. An asteroid is any rocky object that orbits a star and doesn't qualify as a planet.

    A moon doesn't have to be spherical, so that's why the two irregular moons of Mars, Phobos and Deimos (captured asteroids), are still called moons. The rings of saturn are made up of millions of small "moons", but they are (rightfully so) considered a single entity.

    • Re:A couple of definitions (Score:4, Interesting)

      by Scarblac ( 122480 ) <slashdot@gerlich.nl> on Tuesday August 17, 2004 @02:19AM (#9988676) Homepage

      A planet is an object massive enough to become spherical under its own gravitationnal field, that orbits a star.

      Although this is a very logical definition, it's not the one that's usually used. Quite a few objects have already been found that are large enough to become spherical (Ceres [wikipedia.org], Quaoar [wikipedia.org], "Sedna" [wikipedia.org], Ixion [wikipedia.org], to name a few) that aren't classified as planets.

      It seems that the definition of a planet in this solar system is "those nine objects we currently call planets, and nothing else."

  • Damn; nobody RFTA? (Score:3, Interesting)

    by Anonymous Coward on Monday August 16, 2004 @11:59PM (#9988197)
    1) I have to muse, when did Boulder CO become a unit of astronomical significance (and for the trolls: how many library of congress is that?)

    2) Everybody keeps asking, but the reason these are significant is because

    a) they orbit saturn (most asteroids orbit the sun)

    b) they differ from the asteroids in the asteroid belt because, well, they are not in the asteroid belt

    c) their orbit are actually located between two other moons, which is surprising because such area is under heavy bombarbment from other sun-orbiting asteroids and they should have been destroyed long time ago - this sheds light on our understanding of the kuniper belt, asteroids, saturnic satellite formation, etc etc.

    That said, I couldn't make out the things on the picture, so i dunno... could be CCD noise? that would badly suck...

    • 12 (Score:2)

      by aussie_a ( 778472 )
      how many library of congress is that?

      12. Definitely 12.

      • Re:12 (Score:3, Funny)

        by outsider007 ( 115534 )
        how many library of congress is that?
        12. Definitely 12.
        I'm having trouble picturing this. How many football fields would you say that is?

        • Re:12 (Score:2)

          by pjt33 ( 739471 )
          Rugby football, American football, Australian Rules Football, Association football? And for the latter, at least, the pitch size has tolerances which mean the area can vary by something like 50%...

  • OMG! (Score:5, Funny)

    by BollocksToThis ( 595411 ) on Tuesday August 17, 2004 @12:01AM (#9988201) Journal
    Extra! Extra! Scientists find two tiny rocks millions of miles away! Many surprised they haven't been seen before now!

    An artists sketch of the new moons as seen from Earth through a high-powered telescope is shown here

    :

  • Nanoo Nanoo (Score:4, Funny)

    by Anonymous Coward on Tuesday August 17, 2004 @12:02AM (#9988207)
    'The moons are approximately 3 kilometers (2 miles) and 4 kilometers (2.5 miles) across -- smaller than the city of Boulder, Colorado.'


    Even though they're orbiting Saturn, they're closer to Earth than Boulder, Colorado is.

    And by the way, we don't call them "moons" here in Boulder. We refer to them as "planetary companions."

    FYI: Boulder is where Mork and Mindy [sitcomsonline.com] was set.

  • Just Call them Boulder and Little Rock (Score:5, Funny)

    by Louis Savain ( 65843 ) on Tuesday August 17, 2004 @12:18AM (#9988275) Homepage
    They are provisionally named S/2004 S1 and S/2004 S2.

    Why? Just call them Boulder and Little Rock. But then again, maybe not. Some lawyer might sue. Do cities trademark their names?
  • I know Io, Jupiters moon, gets tugged until molten. So, what are the rings/dust/moonies made of? If they are the same materials as Io, what keeps Io from becoming a ring?
    I don't think gravity tugs would do it alone. An impact with a comet into a good sized moon, now pulverized, would do it. So, the rings would be a mix of the comet/moon, probably very different. It would be neat to get more info. If ring could be sampled, bringing back two types of chunks, would argue strongly for impact. It would be a chea
  • Now what we need to do, just to make sure the estimate is correct, is to place one of these moons directly onto Boulder, CO to see if it will in fact cover the entire city.

    Now I know NCAR is there, which is cool and all, but NCAR is on the mountain, and should be O.K.

    I mean, I just want to make sure they are correct about the size estimate. Not that I want to wipe Boulder off the face of the earth or anything like that. Why would anyone want to do that?

    Who's with me? Who is with me? In the name of Sc

  • Proceed with plans (Score:3, Funny)

    by MxReb0 ( 443442 ) on Tuesday August 17, 2004 @12:55AM (#9988424)
    I think the citizens of Boulder will still fit if they squeeze together a bit.

  • What is a Moon? (Score:5, Informative)

    by jebiester ( 589234 ) on Tuesday August 17, 2004 @12:56AM (#9988427)
    There's a very interesting article [space.com] at space.com entitled 'What is a Moon?'.
    • Not exactly related to parent, but to the article in general, you can listen to Cassini encountering the electo-magnetic bow shock as it approached Saturn here [uiowa.edu]. There are also a bunch of other cool space sounds at this site.

  • Is the surface area of the moon the size of Boulder, or is it the cross-section that has similar dimensions? Or is it by volume, based on the idea that only the dirt down to a certain depth can be considered to be within the city limits?
  • when do they find the smaller yet, black rectangular thing in orbit?

    my god, it's full of stars...

  • Moons! (Score:4, Funny)

    by andy55 ( 743992 ) * on Tuesday August 17, 2004 @03:43AM (#9988898) Homepage

    Even the most beautiful moon still doesn't compare to the wonders of Uranus.

    • Even the most beautiful moon still doesn't compare to the wonders of Uranus.
      Does that mean a goatse.cx link would be appropriate here?
      *shudder*

Slashdot Top Deals

Trap full -- please empty.

Close