Want to read Slashdot from your mobile device? Point it at m.slashdot.org and keep reading!


Forgot your password?

Sedna May Have A Moon 76

ArrayIndexOutOfBound writes "The newly found planet Sedna may have a moon. It appears that most astronomers argue that Sedna is only another proof that neither Sedna nor Pluto are really planets. Interestingly, the planet has been found by an 'automated sky survey telescope'..." SYSS Mouse points to a NASA page with more information about "our potential 10th planet. ... It is 130 billion miles away from the sun (900 times Earth's distance from the sun) and has a 10,500 years orbit, compared to Pluto's 230 years around the sun."
This discussion has been archived. No new comments can be posted.

Sedna May Have A Moon

Comments Filter:
  • Value out of bounds (Score:5, Informative)

    by shadowbearer ( 554144 ) on Monday March 15, 2004 @10:06PM (#8574709) Homepage Journal
    Um, the article said it was 13 billion miles out, not 130 billion (now discovering something that size 130 billion miles out would be a real hell of an achievement :)

    There's some theorizing that this may be part of the inner Oort shell; I think it more likely that at that distance it's an outer member of the Kuiper bodies.

    Given the highly elliptical orbit, it's size, and it's apparently odd surface color, it's also possible that it's a body captured by the sun some hundreds of millions or billions of years ago. Now *that'd* be neat.

    • From the second link: "At its most distant, Sedna is 130 billion km (84 billion miles) from the Sun, which is 900 times Earth's solar distance (149 million km or 93 million miles)." Watch out for the miles / kilmetres distinction.
    • by Pumpernickle ( 720937 ) on Monday March 15, 2004 @10:29PM (#8574871) Homepage
      That's true, but not entirely.

      At its most distant, Sedna is 130 billion km (84 billion miles) from the Sun, which is 900 times Earth's solar distance (149 million km or 93 million miles).

      They were just quoting the wrong part of the article in the wrong place.
      • by shadowbearer ( 554144 ) on Monday March 15, 2004 @10:38PM (#8574928) Homepage Journal
        Thank you, I missed the most distant part. Seeing "130 billion km" and thinking "detection at" made my brain stop functioning for a instant, I guess :)

        I was just thinking; we detected Sedna at nearly it's closest part in it's orbit (and probably wouldn't have detected it as easily or at all if it had been much further out). Is it just me, or that say something about the statistical distribution of larger bodies at those distances? Either that or it's a helluva coincidence.

        (Maybe not, but I'm too work-wiped to do the math right now)

      • Oh, and mod parent up further...deserves it for pointing out the distinction (technically we're both right)

    • by kalidasa ( 577403 ) *
      Actually, if you look at the orbits of the KBOs in comparison to Sedna's orbit, even its perihelion is somewhat outside what is theorized to the be outer limit of the Kuiper belt (of the non-scattered KBOs). I looks like there's only one other object, 2000 OO67, that is remotely similar in its distance at aphelion, which is an SKBO; 2003 VB12 is half as far away at aphelion.
      • I looks like there's only one other object, 2000 OO67, that is remotely similar in its distance at aphelion, which is an SKBO; 2003 VB12 is half as far away at aphelion.

        Doesn't that technically make Sedna an SKBO?

        I haven't kept up like I should (work sucks) what *is* the theorized (fuzzy) inner boundary of the Oort cloud's inner members now?

        • According to this page on Sedna [hawaii.edu], it's got a perihelion (closest approach) of 76 AU, outside of the scattering influence of Neptune. 2000 OO67 has an aphelion like Sedna, but a much closer perihelion at 21 AU.

          • by shadowbearer ( 554144 ) on Monday March 15, 2004 @11:37PM (#8575417) Homepage Journal
            From the same page:

            Is Sedna an Oort Cloud Comet?
            From the Classical Oort Cloud - no. The latter consists of objects whose orbits are so large (50,000 AU) that passing stars and galactic tides can alter their properties. Sedna doesn't travel very far out (1000 AU) and is effectively immune to external forces. Also, the inclinations of both Sedna and 2000 CR105 are small (12 and 23 degrees, respectively). These objects know where the plane of the solar system lies. Oort Cloud orbits are random with inclinations all the way up to 180 degrees.

            So What Is It?
            Sedna could be a member of a substantial population of bodies trapped between the Kuiper Belt and Oort Cloud. These would have been emplaced at early times and unseen until recently. 2000 CR105 and Sedna are "just the tip of the iceberg", as they say. The scientific interest lies in how these objects had their perihelia lifted out of the planetary region.

            So it's really on the fuzzy boundary between the two, but closer to the Kuiper belt than to traditional Oort cloud objects. I'd bet there are a lot more objects this close to this size out there. (a hunch, but we're only beginning to explore that region).

            Fascinating. I wonder if we'll ever trace it's orbit back far enough to determine whether it was flung out of the inner system or formed elsewhere. Doubtful. In any case, it's good to know there are objects this size out in that region, just in case we ever *really* need to flee the inner system (tongue in cheek, partially; reading the news gives me that feeling often nowadays..)

      • by Evil Pete ( 73279 ) on Tuesday March 16, 2004 @01:12AM (#8575942) Homepage

        I thought it was a misprint in the article, so I went to Nature news [nature.com]. Sure enough at perihelion it is 13 billion km from the Sun an at aphelion it is 130 billion km. Wow, usually you only see orbits that eccentric with comets. Which makes it seem more like a captured object rather than one that formed in orbit. Wonder white kind of perturbing influence it has on comets in the Kuiper Belt, admittedly its small and in a very big volume ... still ...

        • by I am Jack's username ( 528712 ) on Tuesday March 16, 2004 @09:24AM (#8577368)
          > I thought it was a misprint in the article, so
          > I went to Nature news [nature.com].

          I've been writing for wikipedia about TNOs, and so I've checked links to articles at CNN, WashPost, BBC, etc.. The commercial news companies get so much wrong it's scary.

          In the article you linked to at Nature.com it says "The Spitzer telescope has spied Sedna." and "The Spitzer and Hubble space telescopes later confirmed the find.". Co-discover Mike Brown however, clearly states [caltech.edu] that they "used the 30 meter diameter IRAM telscope, and in collaboration with John Stansberry at the University of Arizona and Bill Reach at the Spitzer Science Certer, we used the Spitzer Space Telescope. Sedna was too small to be detected in either."

          Avoid the corporate media and go to the source, or lacking that know that the news companies exist to make money - not to report the facts.

  • Incorrect links (Score:5, Informative)

    by Rewbob ( 89555 ) on Monday March 15, 2004 @10:20PM (#8574808)
    The first link is about an object named "2004 DW". The second link is about Sedna (previous known as 2003 VB12).

    The newly found moon is orbiting Sedna, NOT 2004 DW.
    The links in the slashdot article are misleading.
  • by Anonymous Coward on Monday March 15, 2004 @10:41PM (#8574946)
    It's a space station.
  • by k4_pacific ( 736911 ) <(moc.oohay) (ta) (cificap_4k)> on Monday March 15, 2004 @11:36PM (#8575408) Homepage Journal
    ...therefore it is a planet.

    Per Webster's:

    moon, n. a natural satellite of a planet

    So there.

    • Websters is hardly scientific canon esp. since some asteroids have moons.
    • by adeyadey ( 678765 ) on Tuesday March 16, 2004 @04:32AM (#8576493) Journal
      Many (non-planet) Asteroids have moons or satellites in orbit about them..
      • by Sanga ( 125777 )
        Most of the Edgeworth-Kuiper objects are hypothesised to be binaries.

        This argument raged on in 1998 (I think) when the intnl body of astronomers wanted to classify Pluto as a Trans Neputinian Object with a special number of 1000.

        Some other TNO having a moon was used as conclusive argument to relegate Pluto to being a TNO (the most significant TNO, if you will).

        I had links to the above ... but I will have leave you only with these
    • I thought "moon" was defined as EARTH's natural satelite. There is only ONE moon, and it's EARTH's.

      Other natural satelites are just natural satelites, with their own names.

      • by p4ul13 ( 560810 ) on Tuesday March 16, 2004 @10:55AM (#8578000) Homepage
        All moons are satelites, not all satelites are moons. OUR moon is called "Luna", just like we've given names to the moons of all the others we've discovered.

        You rarely hear our moon refered to by its actual name because its pretty obvious which one you're talking about when you say "Moon". Same thing with our resident star / sun. Its name on its birth certificate reads "Sol" and our very own Earth is often known as "Terra".

        Oh, and let's not forget that our solar system isn't named just "The Solar System"; it's name is "Stanley".

        • by Baikala ( 564096 )
          You rarely hear our moon refered to by its actual name

          That would be in english speaking countrys, in countrys where the laguage is latin based, like all latin america The Moon is refered to as 'Luna'

  • Mission to Sedna (Score:4, Insightful)

    by adeyadey ( 678765 ) on Tuesday March 16, 2004 @04:40AM (#8576510) Journal
    I understand that the "pluto - new horizons" mission, due hopefully for launch in 2006 (http://pluto.jhuapl.edu/mission.htm) is looking for possible KB targets after getting to Pluto in 2015. I wonder if the planetary line-up would allow one of those targets to be Sedna? (prob not, but you could be lucky..)

    Is there a chart anywhere that gives the location of all these various objects in relation to the solar system, at any given time?

    There is another deep-space mission in the pipeline (ion-drive) to the heliopause and beyond - is Sedna positioned toward the heliopause?

    By the way, Sedna is another good reason to upgrade and keep Hubble going..
    • Is there a chart anywhere that gives the location of all these various objects in relation to the solar system, at any given time?

      Its being reprinted ...

    • I saw one yesterday during Chad Trujillo's colloquium here at CU. Sedna is more or less opposite the Sun from Pluto. Besides, even at 76AU that's more than double the trip for New Horizons. It probably won't make it that far, not to mention the science team still being around.
      • by adeyadey ( 678765 )
        You may be right, but then again, they probably didnt think that Voyager 2 would still be around and in use today when they launched it in 1977.. But yes Sedna is a long way out, and if the line up with Pluto isnt right, forget it..
        • Re:Mission to Sedna (Score:4, Informative)

          by CheshireCatCO ( 185193 ) on Wednesday March 17, 2004 @11:44AM (#8588779) Homepage
          Yes, but if Voyager 2 were to encounter Sedna now, it wouldn't do a bit of good. It doesn't have nearly enough power to collect any useful data, let alone return it. Both Voyagers and Pioneers 10 and 11 have been essentially comatose for many years now: they're alive, but just barely.
          • Re:Mission to Sedna (Score:3, Informative)

            by adeyadey ( 678765 )
            Well, Voyagers 1 & 2 are still alive, albeit with some instruments shut down to conserve power. Here is this weeks activity report

            http://voyager.jpl.nasa.gov/mission/weekly-repo r ts /index.htm

            If they did by chance encounter a large object like Sedna, useful science could be done. Things like the old Vidicon cameras onboard Voyager are not worth keeping on, since they are nowhere near anything that can be usefully filmed, they take a lot of power, are not good in low light, and I think need power to pr
    • To answer my own question, there is a solar system emulator at:


      But alas, no sedna, yet..
  • Planet X (Score:3, Funny)

    by DigiShaman ( 671371 ) on Tuesday March 16, 2004 @05:50AM (#8576691) Homepage
    Oh my GOD!! It's Planet X...quick, someone call Art Bell. The end of the world as at hand...Aarrrggghhhhhhhhaaaaaa!!!

    Ya ya, I'm being silly.

    • Re:Planet X (Score:5, Insightful)

      by RobertB-DC ( 622190 ) * on Tuesday March 16, 2004 @08:48AM (#8577163) Homepage Journal
      Ya ya, I'm being silly.

      You're being silly, but the tin-foil hat crowd is going to have a field day with this baby. Consider the links that they'll find to their planet-killing Nemesis [lbl.gov] object:

      * Highly eccentric orbit with a period ~10k years. They'll make up a mass extinction event to match the planetoid's period, you watch.

      * According to this article [space.com], Sedna is the reddest object found in the solar system except for Mars. Watch the Nemesisians find deep significance in this fact -- we could start a pool to guess when they start calling it "blood red".

      * In the "just enough facts to be dangerous" department, they'll point out that its size can't be determined directly -- that it depends on assumptions about the planet's albedo. If it's darker than expected, then it'll be bigger than expected. Ergo, the scientists are conspiring (as usual) to make it smaller than Pluto. Their "scientific" conclusion: it's the brown dwarf companion to Sol that they've been predicting all along.

      Interestingly (to me at least), I submitted this story as soon as I saw it... and it was rejected almost as quickly. I suspect the editors were looking for a submission without tinfoil hat references [space.com] -- a laudable goal. But even if we Slashdotters are gathered to discuss the real science, our less-informed Internet brethren haven't had much to talk about since the Martians quit shooting down spacecraft...
    • Ya ya, I'm being silly.


      Everyone knows the tenth planet is Mondas, home of the Cybermen.

      Don't come crying to me when you find you don't have any radioactive, gold, nail varnish remover in the house.

  • by dpbsmith ( 263124 ) on Tuesday March 16, 2004 @09:44AM (#8577509) Homepage
    It is always interesting to watch science being created. In this case, you see the nexus of a) actual facts (the discovery of a celestial object) with b) the completely artificial process of trying to name and classify things.

    Is Sedna "really" a planet? Sedna is what it is, of the size and composition that it is, in the orbit that it is in. Sedna does not know or care whether it is "really" a planet or a minor planet or a dwarf planet or a comet.

    Naming disputes are interesting because they always reflect the relative influence and authority of the people giving the names. Not being an astronomer, I can't identify who exactly is jockeying for positioning. Naming and classifying are part of the prescientific process. In a few decades we will probably have a better idea of how real these groupings of similar objects really are.
    • by CheshireCatCO ( 185193 ) on Tuesday March 16, 2004 @11:05AM (#8578083) Homepage
      I am an astronomer and as far as I know, none of us is trying to get this beast classified as a (major) planet. It's most likely (by anyone's definition) an Inner Oort Cloud object. That more than adequately describes it in relation to the rest of the solar system. The whole idea of there being a controversy is more of a media/NASA press-office construction than a reality.

      And while on one level you're right, names are artifical, on another you miss the point of naming entirely. What we call things affect how we consider and perceive those things. Language shapes our thoughts, after all. So classification isn't "prescience" it's a part of the scientific process. Classifying living organisms was the first step towards understanding their relation and then their evolution. Classifying celestial objects plays the same role. It may not be as scientific sounding as producing numbers and plots, but it's important none the less.
      • Inner Oort Cloud object

        Is this really valid terminology? I've always heard Kuiper Belt, and as the Oort cloud is mainly comets (and is un-freaking-godly huge: 50,000 AU) whereas the Kuiper Belt, where this is, is 30-50 AU.

        Last I heard, the Kuiper belt is basically the last rocky objects that formed, and then the Oort cloud is way the hell out there, and it may not even be contiguous (i.e. there might be a gap of 'nothing' between the Kuiper Belt and the Oort cloud). No way to know, of course, as there's
        • by CheshireCatCO ( 185193 ) on Tuesday March 16, 2004 @06:57PM (#8583515) Homepage
          Kuiper Belt Objects are about half and half rock and ice, actually. Beyond about 5 AU you expect icey bodies, since hydrogen compounds are way more common than metals and silicates. (The only trouble being that it has to be cool enough for them to condense.)

          And, yes, there has long been hypothesized to be (based on dynamical models and, I believe, comet distributions) an Inner and Outer Oort Cloud.
          There is some thought that the Inner Oort Cloud should sort of merge with the Edgeworth-Kuiper Belt, although that's mostly speculation.

          Since the Edgeworth-Kuiper Belt is thought to stop around 50 AU or so, this object isn't likely to be a KBO. Inner Oort Cloud seems to fit, though.
      • Language shapes our thoughts, after all.
        A well known hypothesis with very little empirical support. BTW, the thing about Eskimos having hundreds of words for snow is completely bogus; somebody just made up the factoid, and then it got inflated over time in the popular press. Actually English has the same number of words for snow as any Eskimo language; you just have to count all the ones like "corn" and "powder" that do double duty. If language determines what you can think, then how do you explain the fa
        • The Sapir-Wharf hypothesis is certainly adhered to by quite a few anthropologists, and it makes quite a lot of sense. The Eskimo snow digress is, as near as I can tell, either a very odd digression on your part or a helluva strawman you knocked down. As for translating the Bible, you are assuming that it means the same thing in every language, which I think is quite a risky thing to assume.

          But all of this is irrelevent to my point.

          I agree that teaching kids definitions isn't science, it's rote memorizat
    • 9 or 900? (Score:3, Interesting)

      by kippy ( 416183 )
      I was in the Pluto-is-a-planet camp for the most part. That's what I was taught in school. The thing is, I think we're going to find more and more that the difference between planet, comet and asteroid is more of a continuum than a stark separation. With that in mind, consider this: I heard this one astronomer on NPR last night say that he had expected to find hundreds of objects around the size of Pluto way out there. This might mean that if we classify Pluto as a planet, we might also have to say that
      • I think there needs to be a standard definition of a planet. I don't really think this or pluto qualifies as a planet when you compare them with the others.

        I don't think that size should be the only determining factor but it should be a factor. I guess you could start with something that specified a minimum diameter and if it was less then that then you could say it is a planet if it has an atmosphere. That'd probably be to complicated though.

        I don't know a whole lot about astronomy and I'm not pr
        • The problem is that different planet scientists need the term "planet" (as in "major planets") to mean somewhat different things. A dynamicists like myself is concerned with the probable origin and current dynamical behavior of the object. Geologists care about the surface and interior and therefore whether the has been any endogenic geological processes active in the past. Atmospheres people have an entirely different set of concerns. And so forth.
        • Re:9 or 900? (Score:3, Interesting)

          by kippy ( 416183 )
          even if you had a standard, you'd still run into borderline objects. plus, the standards would be just as arbitrary as the nomenclature we use now.

          If you say at least 1000 km diameter, what about a 999km object? What if it's 1001km if measured from a different angle? it's going to be indistinguishable from a 1100km object but it would get a different classification. Same with the atmosphere. Is it required to hold an atmosphere all year long? Why?

          I'm for calling everything that orbits the sun a "pla
          • Re:9 or 900? (Score:3, Interesting)

            by Phisbut ( 761268 )
            I'm for calling everything that orbits the sun a "planetary object"

            Then you'd have one heck of a lot of "planetary objects", considering the huge amounts of asteroids that orbit the sun in the asteroid belt between Mars and Jupiter. Should we give a name to all of them? ;-)

            I, for one, don't thing Pluto is a planet. It's much too small (at least compared to its moon Charon). They both have a similar mass, which means that Charon does not orbit around Pluto, nor Pluto orbit around Charon. They instead

            • Then you'd have one heck of a lot of "planetary objects", considering the huge amounts of asteroids that orbit the sun in the asteroid belt between Mars and Jupiter. Should we give a name to all of them? ;-)

              Sure! We don't have to dig up mythological names for every ball of rock out there but it behooves us to catalogue all the stuff out there for our knowledge, defense and utilization. Numbers are fine. That's how most of the stars are named anyway.

              All I'm saying is that trying to apply artificial and
              • The common understanding won't change but scientific categories should be kept free of arbitrary and possible subjective divisions.
                Woah there! All definitions, scientific and otherwise, are arbitrary. A meter is an arbitrary length as is a foot or forlough, an ounce or a gram are arbitrary units of mass, and every other unit of measure is too.

                However, just because their arbitrary doesn't make them useless.

  • by greenhide ( 597777 ) <{moc.ylkeewellivc} {ta} {todhsalsnadroj}> on Tuesday March 16, 2004 @11:48AM (#8578517)
    What all of us are wondering:

    Is there life on Sedna.

    It says that the rock is made out of ice, and ice, as most of you know, is little more than very cold water which has turned into a solid.

    Water is the source of all life.

    Therefore, there's a very, very good possibility of life on Sedna.

    In 2012, I will turn 35, when I will be legally able to run for President of the United States. At that point, I will make it my platform to make a manned mission to Sedna to search for intelligent life.

    Since Sedna is so cold, I will recommend that astronaut ice cream *not* be eaten on this trip, and instead my astronauts will be given hot cocoa, tea, coffe, and Lipton's instant chicken noodle soup.

    Since Sedna is so far out and is right at the edge of our solar system, I think it might be cool if we put a big billboard that says "Now leaving Solar System. Next star 4.2 light years away. Please do not litter!" And on the other side of the sign, it says, "Welcome to the Solar System! Bad Aliens, please go away." See, that will keep us safe from bad aliens, but encourage the good Aliens to come to engage in tourism, which is ultimately the way we will have to support ourselves in the future, with alien tourism (because all the other work will probably be outsourced to aliens because they will work for cheaper).
  • 10th planet? (Score:3, Informative)

    by confused one ( 671304 ) on Tuesday March 16, 2004 @02:47PM (#8580663)
    Where does everyone keep getting this 10th stuff from... They keep forgetting Quauar and Varuna. Besides, everyone knows there are only 8 planets... :p
  • by Stevyn ( 691306 )
    Something that large moving that fast sounds like a weapon of mass destruction to me.
  • its not a planet. in 2003 they found Quaoar which was supooosed to be more planet like then Pluto, but its long forgotten (which probably means they were wrong). in six months or so this will be forgotten as well.. as for the speculation of a moon orbitting Sedna..because saying the orbitale period of Sedna is slow, it doesn't mean it has a moon. I'm sure that when the 'reddish looking comet' is closer to the Sun it will travel faster and will slow down when going along the aphelion.
  • by DrkAngl ( 763057 )
    Pluto, Sedna, and Quaoar, another Kuiper belt object, should all be classified as planets, simply because, according to standingmethods of definition, they meet all the requirments. They are the correct size, and while it is not known if Sedna and Quaoar can support atmospheres, PLuto has an atmosphere for part of its revolution.

"An open mind has but one disadvantage: it collects dirt." -- a saying at RPI