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Mass of Dwarf Planet Eris 27% Greater than Pluto

jcgam69 writes "When it was discovered in 2005, some thought Eris should be considered the 10th planet of our solar system. Everyone still considered Pluto a planet then. At first, Eris was thought to be slightly larger. Now — with the help of Eris' moon — Eris is known to be 27% more massive than Pluto. If Pluto had remained a planet to the entire community of astronomers, surely Eris would be considered the 10th planet."

220 comments

  1. Haiku on a Distant Rock by Anonymous Coward · · Score: 4, Funny

    Poor lonely Pluto;
    No one loves you now but me.
    And Clyde Tombaugh's urn.

    1. Re:Haiku on a Distant Rock by Ucklak · · Score: 4, Interesting
      --
      if you steal from one source, that is plagiarism, if you steal from many, well, that's just research.
    2. Re:Haiku on a Distant Rock by Forge · · Score: 4, Funny

      Great. Now everyone knows where I found my desktop wallpaper.

      --
      --= Isn't it surprising how badly I spell ?
    3. Re:Haiku on a Distant Rock by Aliriza · · Score: 1

      Hey you are not alone , I too believe in Pluto , it is my 9th planet and it will be forever who are these new comers , where were they when I was a little child , they pop like a lotto millionaires lost relatives , peeeh :)

    4. Re:Haiku on a Distant Rock by Fred+Ferrigno · · Score: 1

      Is it just me or it meant to look like it's coming to a theater near you soon? Seems like your average plot for an animated movie. We've had worse. Remember Space Jam?

    5. Re:Haiku on a Distant Rock by default+luser · · Score: 1

      It would be funnier if the ratios were right. If Pluto were that big, it wouldn't be a dwarf planet.

      --

      Man is the animal that laughs.
      And occasionally whores for Karma.

  2. New Nmemonic by DTC · · Score: 5, Funny

    My Very Excellent Mother Just Serverd Us Nine Pizzas- Excelsior!

    1. Re:New Nmemonic by Wah · · Score: 2, Funny

      and post-plutpwnage it becomes...

      My Very Excellent Mother Just Serverd Us Ninja Excrement.

      --
      +&x
    2. Re:New Nmemonic by Anonymous Coward · · Score: 0

      Shouldn't that be "Mnew Mnemonic?"

    3. Re:New Nmemonic by NewsWatcher · · Score: 1

      The new mnemonic avoiding Plute and Eros, which aren't really planets, just for Slashdotters:

      Many Veteran E-users May Joke Slashdot Upsets Nerds

      --
      If the pattern goes 9am, 10am, 11am, why isn't noon 12am?
  3. Hail Eris! by subl33t · · Score: 5, Funny

    All Hail Discordia!

    Hail yes!

    fnord.

    1. Re:Hail Eris! by prat393 · · Score: 1

      I dedicate the flying rock in space named Eris to the prettiest one.

    2. Re:Hail Eris! by h4rm0ny · · Score: 1


      In classical fashion, Eris has upset the applecart by triggering an argument over whether calling Pluto a planet or not is the fairest decision. What is the gold standard?

      --

      Aide-toi, le Ciel t'aidera - Jeanne D'Arc.
    3. Re:Hail Eris! by Mspangler · · Score: 1

      Stirring up trouble again?

      That is one well-named rock/snowball.

    4. Re:Hail Eris! by Maserati · · Score: 1

      In classical fashion, Eris has upset the applecart by triggering an argument over whether calling Pluto a planet or not is the fairest decision. What is the gold standard?

      Ten tons of flax.

      --
      Veteran, Bermuda Triangle Expeditionary Force, 1992-1951
  4. What can I say... by setirw · · Score: 3, Funny

    ...our beloved ninth planet just got plutowned!

    --
    This message printed on 100% post-consumer recycled electrons.
    1. Re:What can I say... by stefanlasiewski · · Score: 1, Interesting

      I thought Pluto got Erised from history.

      --
      "Can of worms? The can is open... the worms are everywhere."
    2. Re:What can I say... by h2g2bob · · Score: 1

      our beloved ninth planet just got plutowned
      Not really. Pluto and Charon form a binary system. Together they outmass this upstart.
    3. Re:What can I say... by frankie · · Score: 1

      Together they outmass this upstart.
      No, they don't. Charon is only 11% the mass of Pluto.
    4. Re:What can I say... by h2g2bob · · Score: 1

      I stand corrected, sir

  5. If it's round by Profane+MuthaFucka · · Score: 2, Insightful

    it's a planet. If it's orbiting a larger planet, then it's a moon.

    This is just a classification problem. In my company, the secretary takes care of that shit. WHY ARE WE wasting our time with this crap? I don't give a shit if some schoolkid has to memorize dozens of planets. That's between him and his teacher.

    --
    Fascism trolls keeping me up every night. When I starts a preachin', he HITS ME WITH HIS REICH!
    1. Re:If it's round by Anonymous Coward · · Score: 0

      Think about the asteroid belt, man! There's a plethora of round objects to be found just beyond Mars! Planets galore!

    2. Re:If it's round by poopdeville · · Score: 2, Informative

      You're a member of the IAU? Otherwise, you must be using the Royal we.

      In any event, the "dwarf planet" classification is informative. Dwarf planets have sufficiently low mass that they have no managed to clear their orbital path from other massive objects. Their properties are very different, despite orbiting the sun and being round.

      Why use a cluttered ontology when a clean one can be designed?

      --
      After all, I am strangely colored.
    3. Re:If it's round by N3WBI3 · · Score: 1

      Most of those are not round as in spherical. Pluto and Eirs have enough mass to collapse into spheres despite the rigidity of the components that collided to form them. Where they fail the new planet test is by not having enough mass to clear their orbits..

      --
    4. Re:If it's round by Pfhorrest · · Score: 4, Interesting

      it's a planet. If it's orbiting a larger planet, then it's a moon.

      What, no distinction between round moons and non-round moons?

      I think we need to have our system of classifications able to accurately distinguish between:

      - Bodies of sufficient mass that they would undergo fusion if of fusionable composition (stars).
      - Amongst those, ones which are of fusionable composition (active stars) versus those which no longer are (inactive stars).
      - Amongst non-stars, bodies which are of sufficient mass to be approximately round (major planets) versus those which are not (minor planets or asteroids)
      - Amongst planets, those which have an orbit centered on a star (regular planets) versus those which do not (irregular planets).
      - Amongst irregular planets, those which have an orbit centered on another planet (moons) versus those which do not (asteroids).

      Thus, Phobos and Deimos are minor irregular planets, and also moons (call them just "minor moons" since all moons are irregular planets); while similar bodies in the asteroid belt are also minor irregular planets, but are not moons but rather asteroids. Europa and Ganymede are a major irregular planets and also moons ("major moons"). Luna is a major moon. Eris and Pluto (if I understand the irregularity of their orbits correctly) are major irregular planets and also asteroids (or just "major asteroids", for all asteroids are irregular planets). Earth, Mars, etc are major regular planets, and schoolkids can memorize those and ignore the rest; for simplicity of terminology we can always assume "major" and "regular" unless specified otherwise, so "planet" alone refers just to bodies like those.

      There now, everybody happy? Pluto is a planet; it's even a major planet; however, it's an irregular major planet and thus not a "planet" simpliciter.

      --
      -Forrest Cameranesi, Geek of all Trades
      "I am Sam. Sam I am. I do not like trolls, flames, or spam."
    5. Re:If it's round by mdwh2 · · Score: 1

      Quite a few of them are round I believe, we'd certainly have quite a few extra.

      Though that wasn't the OP's definition anyway, he was saying that anything orbiting the sun should be a planet. Not that I think there's a problem with that - we use his definition for moon, after all, there's no awkward requirements for "must be round" or "must be minimum mass" or "must clear its orbit". As long as we can identify a particular piece of rock, it gets labelled a moon.

    6. Re:If it's round by mdwh2 · · Score: 1

      Oops, didn't see the subject line - I see he did specify a planet should be round. But as I say, quite a few of the asteroids are.

    7. Re:If it's round by N3WBI3 · · Score: 1

      Can you point me at a round asteroid in the belt?

      --
    8. Re:If it's round by Paradise+Pete · · Score: 5, Funny
      Can you point me at a round asteroid in the belt?

      OK, look up. A little more to your left. A bit more. OK, just a little bit more. Nope, that's too far. Just a hair back to your right. There! See it?

    9. Re:If it's round by Anonymous Coward · · Score: 0

      Ceres comes to mind.

    10. Re:If it's round by mdwh2 · · Score: 3, Informative

      At the least, Ceres, Vesta, Pallas and Hygiea ( http://space.newscientist.com/article.ns?id=dn9761 &feedId=online-news_rss20F53 ). Admittedly not as many as I'd first thought there might be.

    11. Re:If it's round by jonatha · · Score: 2, Informative

      Ceres and Vesta

      --
      The SCO lawsuit makes me wish my company were in Utah. We need a new building.
    12. Re:If it's round by Propaganda13 · · Score: 1

      Though that wasn't the OP's definition anyway, he was saying that anything orbiting the sun should be a planet. Not that I think there's a problem with that


      Halley's Comet orbits the sun in a highly elliptical orbit.
      Asteroids orbit the sun.
      Round man-made satellites could orbit the sun.

      Slight stretch - If a moon breaks out of planetary orbit or the planet is destroyed, does the moon become a planet since it orbits the sun?
    13. Re:If it's round by shaitand · · Score: 1

      Is there some reason planetism should be sacred and include only a few objects? I fail to see a reason that asteroids couldn't be both asteroids and planets. After all, there are plenty of asteroids that would not be planets under this definition.

    14. Re:If it's round by Anonymous Coward · · Score: 1

      I think you need one further tweak to your classification system to deal with the case of double planets. What if there are two planets of equal mass, orbiting one another, with the pair of them in turn orbiting a star? Are they both regular planets, both irregular planets, or one of each - and if so, how do you choose? What if their masses are slightly different - how different do they have to be before you can designate one of them as the primary?

      There's a fairly easy solution to this, which I'd like to suggest. Look at the centre of mass of the two-planet system. If it is inside the larger planet, then that planet is the primary, and the other one is a moon. This would designate Pluto and Charon as a double-planet system, but leave Earth and Luna as a planet and its moon.

      Incidentally, I think you've misunderstood things slightly in designating Pluto (and Eris) as irregular planets under your classification system. Pluto still orbits the Sun - it just has a more eccentric orbit than any of the other planets. If you want to designate it as irregular, and other planets as regular, then you need to decide exactly how much eccentricity is necessary for irregularity.

    15. Re:If it's round by Pfhorrest · · Score: 1

      There's a fairly easy solution to this, which I'd like to suggest. Look at the centre of mass of the two-planet system. If it is inside the larger planet, then that planet is the primary, and the other one is a moon. This would designate Pluto and Charon as a double-planet system, but leave Earth and Luna as a planet and its moon.

      Yes, this is what I meant by a planet being a moon if it's orbit is centered on another planet; that meaning, if the point it orbits (the center of mass of the combined system) is within another planet. If the two objects mutually orbit a point outside either of them, then I'd classify them both as irregular planets. However, you're right that there is still the questionable scenario where that system of two irregular planets itself regularly orbits a star; oughtn't that be distinguished somehow from two objects orbiting each other but NOT together in a regular orbit around a star? Also, I'm rather happy with my system for it's technically allowing Earth-Luna to qualify as a system of two major planets (both round but not fusionable bodies) while also qualifying as a planet and its moon.

      Incidentally, I think you've misunderstood things slightly in designating Pluto (and Eris) as irregular planets under your classification system. Pluto still orbits the Sun - it just has a more eccentric orbit than any of the other planets. If you want to designate it as irregular, and other planets as regular, then you need to decide exactly how much eccentricity is necessary for irregularity.

      I intended to mean something similar to the above with that criterion; however, and hence my qualification in the original post, I'm not entirely sure where the center of mass of, say, the Mars-Sun system is, relative to the Pluto-Sun system. Are both within the sun? Or both outside, what with them all having elliptical orbits and all? What about a random comet or asteroid?

      Also, it dawns on me that there's an additional scenario I had not considered: a small star orbiting a much larger star such that their center of gravity is within the larger star, which seems like it ought to be distinguished from double star systems where that is not the case (where their center of gravity is not inside either of them). This in turn makes me realize that there's really only two variables we need to classify things by here:

      How big is it? (Fusionable, round, or neither?)
      What does it orbit*? (A star, a planet, or nothing?)
      (*Restricted here to mean the center of mass of the system of which it is a part is within another object in the system).

      The above disproportionate star systems would be a (fusionable,star) orbiting a (fusionable,nothing). Earth would be (round,star) orbiting a (fusionable,nothing). But my brain is starting to wind down now so I think I'm going to stop pursuing this train of thought before I end up babbling even more nonsense...

      --
      -Forrest Cameranesi, Geek of all Trades
      "I am Sam. Sam I am. I do not like trolls, flames, or spam."
    16. Re:If it's round by CWRUisTakingMyMoney · · Score: 1
      Amongst planets, those which have an orbit centered on a star (regular planets) versus those which do not (irregular planets).

      That definition can't hold, because the barycenter of the Jupiter/Sun system lies outside the sun itself. Surely you would consider Jupiter a regular planet, but your definition makes it irregular. My idea: planets should be defined as being sufficiently massive to be essentially round, and having an path through space which is always concave to the star. Now, Earth's moon has this characteristic as well (unique in our solar system, this would make Earth and the "moon" a double planet system), but I think perpetual orbital concavity makes more sense than barycenter location.

      (Although I admit that I ultimately think that these definitions are completely subjective and of little if any use.)

      --
      Those who anthropomorphize science and/or nature already believe in an intelligent designer.
    17. Re:If it's round by Seahawk · · Score: 1



      Would that do?

      There are more, btw.

    18. Re:If it's round by master_p · · Score: 1

      Yeap, just to right of the Argo.

    19. Re:If it's round by Xtifr · · Score: 1

      > "What, no distinction between round moons and non-round moons?"

      Round moons are planets; non-round moons aren't. That was implicit, and no other distinction is needed. I basically agree with grandparent poster, and think that any system of categorization which claims that Mercury is more like Jupiter than it is Ceres is...utterly brain-dead.

    20. Re:If it's round by Anonymous Coward · · Score: 0

      Ceres.

      But it depends upon what you mean by "round". Even the Earth is approximated as an oblate spheroid rather than a perfect sphere, so how "round" do you mean? Saturn is quite oblate. So, how close to spheroidal does an object have to be? You're still picking a rather arbitrary boundary.

      I think this was one of the candidates considered for the definition of a planet, but like most of them, it has problems too.

    21. Re:If it's round by mdwh2 · · Score: 1

      Interesting examples. As I say, it's not clear to me why "planet" should be a special restricted category, whilst "moon" isn't.

      Round man-made satellites could orbit the sun.

      Well I think a sensible restriction is any natural satellite - again, just as moon means any natural satellite of a planet.

      Slight stretch - If a moon breaks out of planetary orbit or the planet is destroyed, does the moon become a planet since it orbits the sun?

      I think it's reasonable and sensible to say that the moon becomes a planet in these cases. Just as some of the planets' moons may have been captured planets/asteroids, but we still include them as being moons now.

    22. Re:If it's round by Profane+MuthaFucka · · Score: 1

      Round planets are moons if they are orbiting another planet. If you've got a bunch of things orbiting each other, the big one is the planet and all the rest are moons.

      Moons don't have to be round, but planets do. Irregular asteroids orbiting each other aren't planets or moons, because planets are round, and moons orbit planets. They're just two asteroids orbiting each other, and that's it.

      --
      Fascism trolls keeping me up every night. When I starts a preachin', he HITS ME WITH HIS REICH!
    23. Re:If it's round by Profane+MuthaFucka · · Score: 1

      The point is that distinctions without meaning are hardly what I'd call a clean ontology. The difference between a rocky planet and a gas giant is far far more significant than your orbit clearing mumbo-jumbo.

      There's no significance to orbit clearing, thus distinguishing that characteristic is arbitrary.

      Planets are round and orbit the sun. Moons are smaller objects which orbit the largest object in their planetary system. Within that you have a lot of room for domain specific ontologies to classify everything in the system. Remember, we're not trying to come up with a clean ontology here, we're defining the word "planet" without restricting other classification schemes which are useful to people studying different things in the solar system.

      --
      Fascism trolls keeping me up every night. When I starts a preachin', he HITS ME WITH HIS REICH!
    24. Re:If it's round by Profane+MuthaFucka · · Score: 1

      I'm aware of the couple of round asteroids. They're planets.

      What *kind* of planets? They're not gas giants, or trans-Neptunians, or Kuiper belt objects. They're associated with the asteroids, so if that distinction is meaningful to you, then make it.

      --
      Fascism trolls keeping me up every night. When I starts a preachin', he HITS ME WITH HIS REICH!
    25. Re:If it's round by poopdeville · · Score: 1

      The point is that distinctions without meaning are hardly what I'd call a clean ontology. The difference between a rocky planet and a gas giant is far far more significant than your orbit clearing mumbo-jumbo.

      Not if you're studying the object's dynamics. If an object hasn't cleared its orbit, its trajectory, rotation, and development are dominated by interactions with other objects in the belt. This really is significant, despite your claims to the contrary.

      Remember, we're not trying to come up with a clean ontology here, we're defining the word "planet" without restricting other classification schemes which are useful to people studying different things in the solar system.

      You keep saying "we". I find it difficult to believe that you speak for the IAU in any respect. And in any case, people aren't contractually bound to use the IAU's nomenclature.

      --
      After all, I am strangely colored.
    26. Re:If it's round by Profane+MuthaFucka · · Score: 1

      OK, so it's significant. You made a good case, so I can accept that for purposes of the argument.

      Is this significance greater than the distinction between rocky planets and gas giants? Don't all three items (rocky cleared orbit, rocky non-cleared orbit, gas giant) all fit under the umbrella of "planet?"

      Remember, the discussion isn't about a logical classification for everything. It's the definition of planet. I would submit that allowing the detail levels of your classification to unnecessarily contaminate the definitions of the broad levels of your classification is wrong. The definition of the broad classification (planet) is being unneccessarily attentive to details that should be addressed at lower levels. At the high level we have planets (rounded because of their own gravity) and below that we have other classifications which are appropriate to what people care about. At lower levels, people can argue all they want about rocky planets which have cleared their orbits, and those which have not.

      An additional attraction to proper design of your classifications is that we're not going to revisit what a planet is in another 10 years after we learn more. We're instead going to be arguing about sub-classes of asteroids, or families of comets. The lack of stupid planet-argument spectacles will be a GOOD thing for astronomy.

      --
      Fascism trolls keeping me up every night. When I starts a preachin', he HITS ME WITH HIS REICH!
    27. Re:If it's round by poopdeville · · Score: 1

      Is this significance greater than the distinction between rocky planets and gas giants? Don't all three items (rocky cleared orbit, rocky non-cleared orbit, gas giant) all fit under the umbrella of "planet?"

      For the purposes of celestial mechanics, a rocky object with a cleared orbit and a gas giant with a cleared orbit are going to behave the same. But a rocky object without a cleared orbit won't. The gas giant and rocky object with cleared orbit won't develop through accretion much more. The center of mass of the dynamical system they dominate will be inside the objects. This is not true of objects that haven't cleared their orbit.

      I'm not completely unsympathetic to your point. But I think you're missing a larger issue. When you study the dynamics of an object without a cleared orbit, you must study the other objects in the orbit as well. Moreover, they are all equally parts of the same dynamical system. The system must be taken as a whole, and calling some components planets gives them undue primacy.

      An additional attraction to proper design of your classifications is that we're not going to revisit what a planet is in another 10 years after we learn more. We're instead going to be arguing about sub-classes of asteroids, or families of comets. The lack of stupid planet-argument spectacles will be a GOOD thing for astronomy.

      I wouldn't count this as progress. They would still be arguing over their ontology, not doing real science. But I agree. Establishing linguistic conventions is important.

      --
      After all, I am strangely colored.
    28. Re:If it's round by Anonymous Coward · · Score: 0

      What if you have nearly identical binary planets, which only have a 1% difference in mass/size? Do you still name the one with more mass the "planet" and the smaller one the "moon"?

      Our terminology is limited by our very limited experience with very large clumps of matter.

    29. Re:If it's round by Profane+MuthaFucka · · Score: 1

      Is a binary planet an interesting thing? Do we have a reason for making the category? If it is, then yes, make a category for a binary planet. Otherwise, it's a planet and a moon.

      Think about it. If I had a file folder for car receipts, is it useful to have two sub-folders for oil change receipts and another for gasoline receipts? If so, make the categories. If not, dump them into one folder.

      Our current situation with having planets and dwarf planets is like having car receipt folders for the categories "combustible car fluids" and "non-combustible car fluids". Sure, it's a valid categorization, but it's not very useful.

      --
      Fascism trolls keeping me up every night. When I starts a preachin', he HITS ME WITH HIS REICH!
  6. sell outs by Anonymous Coward · · Score: 0

    if you call it a dwarf planet it only means that you're a sell out poseur. you can't take my planets from me!

  7. So let 'em both in by FlyByPC · · Score: 2, Insightful

    Pluto is big enough to have a moon (okay, so Pluto/Charon is really a double planet). Eris is more massive than Pluto. Sounds like they should both get to (re)join the club. Why not?

    --
    Paleotechnologist and connoisseur of pretty shiny things.
    1. Re:So let 'em both in by ushering05401 · · Score: 5, Interesting

      The funniest thing to me is that we are so fixated on the planet/not-a-planet debate. Let em both in, don't let either in...

      Both bodies will continue to be studied, and when the time comes, they will be exploited for their natural resources.

      This debate will only matter fifty years from now when we actually begin mining other planets and mining related laws discriminate between bodies with different scientific designations.

      Regards.

    2. Re:So let 'em both in by Kelson · · Score: 1

      Pluto is big enough to have a moon (okay, so Pluto/Charon is really a double planet).

      Sure, but the asteroid Ida has a moon, Dactyl, as well, so I'm not sure that's useful criteria for planethood.

    3. Re:So let 'em both in by KC1P · · Score: 1

      >Eris is more massive than Pluto. Sounds like they should both get to (re)join the club. Why not?

      Because they were both discovered by Americans. Don't be naive!

    4. Re:So let 'em both in by hoopshank · · Score: 1
      Pluto is big enough to have a moon (okay, so Pluto/Charon is really a double planet)

      Well Earth / Moon is also really a double planet. And how many know that Earth has two more distant and much smaller moons?

    5. Re:So let 'em both in by jae471 · · Score: 1
      I know Cruinthe, but most don't consider co-orbital objects to be satellites (otherwise Trojans have to be considered moons also).

      What is(are) the other(s)?

    6. Re:So let 'em both in by arth1 · · Score: 1
      In my opinion, the solar system consists of what a visiting alien would notice:
      • One star, Sol
      • Two large gas planets: Jupiter and Saturn
      • Two medium ice gas planets: Uranus and Neptune
      • Two small rock planets: Venus and Tellus
      • Various rock debris mostly between the inner planets and the gas giants (including Mars and the other asteroids).
      • Various ice debris mostly outside the medium ice gas planets (including Pluto, Eris and the other transneptunian objects)

      Mercury and Mars are just too small to be counted (Mars is only around 10% of Earth's mass and 15% of Earth's volume).

      Regards,
      --
      *Art
    7. Re:So let 'em both in by syousef · · Score: 1

      I couldn't care less if Pluto is classified as a planet or not. What I do care about is that the definition for a planet makes sense. The current one voted by the IAU is a joke. Dwarf Planets are not Planets (confusing and unscientific calssification), bodies orbiting other stars are not planets by definition. Therefore years of literature about extra-solar planets is made technically incorrect in one fell stupid swoop. If you're going to reclassify Pluto as something other than a planet, go for it, but these definitions make about as much sense as classifying Pluto as a ham sandwich.

      --
      These posts express my own personal views, not those of my employer
    8. Re:So let 'em both in by bytesex · · Score: 1

      Tellus ? Is that Terra, as in Earth ? Did I miss something ?

      --
      Religion is what happens when nature strikes and groupthink goes wrong.
    9. Re:So let 'em both in by Ihlosi · · Score: 1
      Mercury and Mars are just too small to be counted (Mars is only around 10% of Earth's mass and 15% of Earth's volume).



      Both are close enough to the sun and large enough to be fairly noticable.



      It probably depends on what kind of planet the alien would find habitable/interesting/valuable. If their main interest lies in hot Jupiters, our solar system would get a "nothing interesting here, let's try the next one". If they're interested in the most massive objects, it would be "One sun, one smallish and one tiny gas planet, and assorted debris"

    10. Re:So let 'em both in by Anonymous Coward · · Score: 0

      It may matter to Eris - she can be a real bitch, and she hates the "d" word before her planet designation.

    11. Re:So let 'em both in by tbone1 · · Score: 1
      I know you were joking, but when I followed the IAU debate, there did seem to be a whiff of anti-Americanism about. I think the end result, with Pluto et al classified as non-planets, is the right one, but the definitions hav weaknesses, and some of the non-American astronomers' statements could easily be read with the accent of the French taunter from Monty Python and the Holy Grail.

      --

      The Independent: Reverend Spooner Arrested in Friar Tuck Incident - ISIHAC, Historical Headlines
    12. Re:So let 'em both in by PhetusPolice · · Score: 1

      Actually, there a lot of asteroids in the asteroid belt that revolve around each other. Actually, most of the asteroids are just a bunch of little asteroids that revolved around each other long enough and ffinally compressed.

    13. Re:So let 'em both in by wikinerd · · Score: 1

      I'm actually quite relieved that Pluto was demoted from planethood. I never considered it a true planet. If we let Pluto back into the planetary club, then we ought to do the same with many other, probably yet undiscovered, TNOs (Trans-Neptunian Objects). Pluto is just a big TNO, not a planet.

  8. Pluto is still a planet by Ryunosuke · · Score: 1

    Some of us still consider Pluto a planet.

    1. Re:Pluto is still a planet by Anonymous Coward · · Score: 0

      Some of us still consider Pluto a cartoon dog.

    2. Re:Pluto is still a planet by Anonymous Coward · · Score: 0

      Some of us consider Titan a planet too.

      Of course those people are wrong, and so are you.

    3. Re:Pluto is still a planet by Anonymous Coward · · Score: 0

      ...and the rest of us are qualified to have an opinion.

    4. Re:Pluto is still a planet by geekoid · · Score: 3, Insightful

      Some of us still consider that the world is flat.

      Change can be hard.

      --
      The Kruger Dunning explains most post on /. http://en.wikipedia.org/wiki/Dunning%E2%80%93Kruger_effect
    5. Re:Pluto is still a planet by nbert · · Score: 1

      you are trying to make fun of this, but It's easy to fool the untrained eye.

    6. Re:Pluto is still a planet by phishen · · Score: 0

      Pluto is only 73% the planet Eris is.

    7. Re:Pluto is still a planet by Anonymous Coward · · Score: 1

      Some of us still consider Pluto a cartoon dog.

      You must be Goofy.

    8. Re:Pluto is still a planet by Jarjarthejedi · · Score: 1

      Well except for the fact that one is a completely arbitrary judgment which doesn't affect science at all and the other is something that has been proven wrong by evidence numerous times (sorry flat-earthers) you have it right.

      --
      There are two kinds of fool One says 'This is old therefore good' Another says 'This is new therefore better'- Dean Ing
    9. Re:Pluto is still a planet by Anonymous Coward · · Score: 0

      Some of us still consider Pluto a planet.

        Yeah, and Australians consider Vegemite a food.

    10. Re:Pluto is still a planet by Anonymous Coward · · Score: 0

      The problem is that this is about classification, not findings. Planets are just big asteroids after all.

      Some big asteroids are round. Some have cleared their orbit from other objects. Some have an athmosphere. Some of them are liquid under the surface. Some are of historical significance. Some have sufficient magnetic field to prevent harmful particles from killing all life on their surface. The list of typical properties of "planets" is endless.

      Attempting to make a "scientific" distinction by picking some of these at random is a mistake.

    11. Re:Pluto is still a planet by Anonymous Coward · · Score: 1, Funny

      For sufficiently curved definitions of flat.

    12. Re:Pluto is still a planet by Anonymous Coward · · Score: 0

      Geekoid, the point is nothing has changed. Pluto is still in the same orbit, made of the same amount of the same stuff. It looks the same, smells the same, drinks the same beer, wears the same awful t-shirt.

      All that has changed is a definition of a word defined by humans for humans to use. I think that failing to include the "big nine" was a mistake, since it puts the technical definition at odds with common usage.

      PS next time you read a map, be sure to correct for the flat-earth approximation it makes won't you, otherwise you might drop off the edge of the earth and land up stuck forever in definition-makes-reality world.

    13. Re:Pluto is still a planet by Cro+Magnon · · Score: 1

      Some of us still consider that the world is flat


      Only in Kansas! And, in their defense, that part of the world IS flat.
      --
      Slow down, cowboy! It has been 4 hours since you last posted. You must wait another few hours.
    14. Re:Pluto is still a planet by Anonymous Coward · · Score: 0

      Can the untrained eye even see Pluto? I'm not sure how it could be considered to wander the sky if you can't.

  9. Silly question by slickwillie · · Score: 0

    but wouldn't they have to know the mass of Eris's moon in order to make the calculations?

    (BTW, what ever happened to naming it Xena?)

    1. Re:Silly question by Bramantip · · Score: 3, Informative

      Gravity provides the centripetal force needed to keep satellites in orbit. If you focus on the simple case of circular orbits, you can use the centripetal force formula with the law of gravity to determine the mass of a planet. Simply set the force of gravity equal to the centripetal force and solve for the mass of the planet M.

      M = r * v^2 / G

      The period of Eris' moon provides another way to calculate its mass.

      Period T = 2pi * sqrt(r^3 / G*M)

      Thus I imagine the various images of the moon provided a way to calculate its period and indirectly determine the mass of the central body.

      However the article doesn't give any specifics. It would be interesting to know what methods they used and the degree of accuracy of their measurements.

      JJ +

    2. Re:Silly question by Anonymous Coward · · Score: 0

      If you have full text access to Science the relevant article is here:

      http://www.sciencemag.org/cgi/content/full/316/583 1/1585

    3. Re:Silly question by Anonymous Coward · · Score: 0

      but wouldn't they have to know the mass of Eris's moon in order to make the calculations?

      Nope. The orbit of a satellite doesn't depend on its mass. (Think of a space shuttle and an EVA astronaut orbiting alongside one another - they stay in the same orbit, even though one is bigger than the other.) If you know the satellite's altitude, and its period, you can calculate the mass of the primary.

    4. Re:Silly question by Jehosephat2k · · Score: 1

      No. The period of revolution is independent of the mass of the moon and solely dependent on the mass of the planet and the distance from it.

        T^2 ~ r^3/M

      http://en.wikipedia.org/wiki/Kepler's_laws_of_plan etary_motion

      Hubble can measure r. We can measure T by watching it over time. Hence, M.

    5. Re:Silly question by ars · · Score: 1

      Nope, both you and the couple of people above you are wrong.

      The orbit of the moon does depend on the mass of the moon.

      The only time it's ignored is if the mass is negligible compared to the other body. So yah, the equations are right - but only in some cases (what do they say about a little knowledge being a dangerous thing?)

      That may be the case here, I don't know. I didn't check for estimates of the mass of the moon of Eris.

      But if the moon is large, then yes, you do have to take it's mass into account.

      But it's not so hard to do so - just assume both the moon and the planet have equal densities, and you can solve it.

      --
      -Ariel
    6. Re:Silly question by Jehosephat2k · · Score: 1

      M is the mass of the primary, silly, not the moon. Duh.

  10. it matters? by mastershake_phd · · Score: 1

    What does it matter what its classified as? Its still a big frozen chunk of rock in the middle of nowhere. I guess the only difference is if it will be taught in school.

    1. Re:it matters? by mastershake_phd · · Score: 1

      Has anyone come up with a new mnemonic device? My very eager mother just...

    2. Re:it matters? by Anonymous Coward · · Score: 0

      What does it matter what its classified as? Its still a big frozen chunk of rock in the middle of nowhere. I guess the only difference is if it will be taught in school. Of course it will be taught in school. The only thing this affects is whether kids are told God made it before or after lunch on the first day.
    3. Re:it matters? by Anonymous Coward · · Score: 0

      What matters is not about pluto,.. but about how we define a planet.. if we change the criteria (theres a few properties a planet must have, probably best to look it up) to somehow include the body called pluto.. we must then also include over 30 other largish bodies that are orbiting the outer solar system.. and possibly some asteroids. It gets really messy. I'm a cynic, and I think the influences in the USA are just unimpressed because they want pluto, come hell or high water (preferably hell) to be a planet because it was discovered by an American. Despite it now being the first dwarf planet discovered.. officially anyway.

    4. Re:it matters? by Anonymous Coward · · Score: 0

      A rose by any other name, would it have the same mass and orbital parameters?

  11. Plan Nine by Digital+Vomit · · Score: 1

    You see? You see? Your stupid minds...stupid! Stupid!!

    (Okay, so it's "Eris" and not "Eros". Sue me.)

    --
    Modern copyright is theft of culture from everyone and it retards the progress of the useful arts and sciences.
  12. Kuiper belt by blind+biker · · Score: 2, Insightful

    The Kuiper belt, I am sure, contains still some surprises for us. Perhaps many surprises, and who knows, maybe some of them unpleasant. I wouldn't be surprised if Neptune one day grabs one of those rocks and launches it over here. That'll be lots of fun.

    --
    "The agriculture ministry is not in charge of Gundam" - Japanese ministry official.
    1. Re:Kuiper belt by bryan1945 · · Score: 1

      "The Kuiper belt, I am sure, contains still some surprises for us."

      Yeah, like finding Cthulhu there instead of the Pacific ocean. Then it won't be Neptune launching the rocks....

      (ok, go for the Uranus jokes now)

      --
      Vote monkeys into Congress. They are cheaper and more trustworthy.
    2. Re:Kuiper belt by Harry+Coin · · Score: 1

      Cthulhu is most certainly in the Pacific Ocean.

      You're thinking of the Mi-Go.

      --
      That's pre 7-11 thinking....
    3. Re:Kuiper belt by bryan1945 · · Score: 1

      Dang, I forgot about those guys! Been a while since I read some good ol' HP.

      --
      Vote monkeys into Congress. They are cheaper and more trustworthy.
  13. Re:Huge purple penis by Poromenos1 · · Score: 2, Funny

    You got it wrong, that's Uranus.

    --
    Send email from the afterlife! Write your e-will at Dead Man's Switch.
  14. Kallisti by Anonymous Coward · · Score: 0

    all hail, etc.

    1. Re:Kallisti by Anonymous Coward · · Score: 0

      fnord

  15. every one knows . . . by jd142 · · Score: 2, Informative

    That Mondas is the 10th planet. Duh.

    1. Re:every one knows . . . by Burb · · Score: 1

      You are a Doctor Who fanboy and I claim my ten pounds.

      --

  16. grandfathered by Secret+Rabbit · · Score: 0, Flamebait

    I still don't understand why Pluto couldn't be 'grandfathered in' as a planet and still have the new definition. It's a way that everyone could have there way. This new guy would be a 'dwarf planet' (or whatever these politicians want to call it this week) and we'd still have Pluto if only for historical reasons.

    Then again, there are those of us that have just ignored this ruling all together and still consider Pluto a planet.

    Quite frankly, I'm really getting sick of the jackasses sitting around drinking whisky coming up with new names for things from time to time in an attempt to justify there existence. I really don't think that this one is going to be dropped for some time to come.

    1. Re:grandfathered by Metasquares · · Score: 2, Informative

      This is science we're talking about. 'Grandfathering' a planet would be like declaring 1 a prime because it was treated as one in the past. If we did this, we'd have to start explicitly making exclusions for the grandfathered planet/number ("all planets except Pluto are...").

      Consistency is important in science.

    2. Re:grandfathered by Tumbleweed · · Score: 1

      Keep in mind, there are those of us who consider the definition of a planet as wrong, and the 'reclassification' as merely an attempt to exclude Pluto as a planet for the sake of scientific contrariness.

    3. Re:grandfathered by ZombieWomble · · Score: 2, Informative
      Except this isn't really science. This is a labeling problem. The only things this definition affects are other labeling issues, and occasional problems of ambiguity in certain forms of casual conversation. I can think of no real technical situation where this would cause an issue, and the whole fuss is rather silly and gives some people a fairly low opinion of science.

      As an example I was watching some random evangelical show late one night (I had insomnia) while the main debate was going on. There was a whole segment dedicated to how scientists "didn't know" whether Pluto was a planet or not and how this clearly meant that they couldn't possibly make definitive statements on things like evolution and so forth. Of course to anyone involved in science the flaw in this argument is obvious - and neatly serves to indicate how the "planet" label isn't really that significant from any technical point of view.

    4. Re:grandfathered by Anonymous Coward · · Score: 0

      "Planet" is both a science term and a common trivia topic. Trivia tests if you know astronomy, not the other way around. Science decides, and trivia follows.

    5. Re:grandfathered by mdwh2 · · Score: 1

      I demand that we also "grandfather" in Ceres, Pallas, Juno, and Vesta, for historical reasons.

      Some of us still consider them to be planets, and are really getting sick of the jackasses who keep changing their names (minor planets? asteroids? dwarf planet?)

    6. Re:grandfathered by Secret+Rabbit · · Score: 1

      You're example fails to prove your point as 1 IS considered prime by some.

      But, even using your example, your example fails. If you knew anything about number theory you'd realize that 1 HAS to be treated as a special case in... many proofs.

    7. Re:grandfathered by Oktober+Sunset · · Score: 1
      Hey, they still define current as flow of positive charge, when really it's the negative charge that flows, just because that's how it was defined in the past.

      If they can be inconsistent for electrons, why can't they be for planets?

    8. Re:grandfathered by Anonymous Coward · · Score: 0

      The question is answered on a case by case basis. Those who are dealing with current everyday decided not to change anything. Those who are dealing with celestial bodies everyday decided to change something.

    9. Re:grandfathered by Metasquares · · Score: 1

      I find it ironic that you question my knowledge of number theory, as it's a field I've done research in. I realize that 1 must be treated as a special case in many proofs, thus the widespread use of the term "nontrivial", but thankfully, it does not have to be invoked every time a proof involving primality arises. That is what I was trying to illustrate.

      As for considering 1 a prime, I suppose that's a question of opinion, but it doesn't really obey enough properties of the primes to warrant that designation in my mind (or the minds of most mathematicians, as far as I know). For instance, it's not relatively prime to any other primes - something that can be said of every other prime number. It's a very nice thing to say that any two distinct primes are coprime, and declaring 1 prime screws that up.

    10. Re:grandfathered by Anonymous Coward · · Score: 1, Funny

      Thus raising the question, "What is the current definition?"

      --AC

    11. Re:grandfathered by Anonymous Coward · · Score: 0

      No offense, but in that case you are the politician drinking whisky who wants the people to whom it matters to change their definition because.. well because it suits you.

      You can call pluto a planet, a flying meatball, or an cjase for all I care, but if scientists decide to call pluto a dwarf planet, that's their business, and I can't see why they (and I) should give a sh*te about your politically correct yoursness.

  17. It's not like we could go there anyway... by MobileTatsu-NJG · · Score: 1

    .. the planet is defended by 5 lions.

    --

    "I like to lick butts!" by MobileTatsu-NJG (#32700246) (Score:5, Informative)

  18. It was a nickname by Kelson · · Score: 3, Informative

    (BTW, what ever happened to naming it Xena?)

    Xena was never more than an unofficial nickname. No one, including the person who discovered it, ever intended for Xena and Gabrielle to be the official names for this pair of heavenly bodies.

    1. Re:It was a nickname by jollyreaper · · Score: 1

      Xena was never more than an unofficial nickname. No one, including the person who discovered it, ever intended for Xena and Gabrielle to be the official names for this pair of heavenly bodies. Plus the Christians would go nuts, seeing it as a sign of further support for the homosexual agenda.
      --
      Kwisatz Haderach
      Sell the spice to CHOAM
      This Mahdi took Shaddam's Throne
    2. Re:It was a nickname by tyrantking31 · · Score: 1

      There already are two heavenly bodies named Xena and Gabrielle. If you know what I mean.

      --
      We willna be fooled again!
    3. Re:It was a nickname by Jarjarthejedi · · Score: 1

      Hehe, he said heavenly body and Xena...hehe

      --
      There are two kinds of fool One says 'This is old therefore good' Another says 'This is new therefore better'- Dean Ing
    4. Re:It was a nickname by The+One+and+Only · · Score: 3, Informative

      However, Eris's moon Dysnomia was named after a mythological demon of lawlessness.

      --
      In Repressive Burma, it's not just your connection that dies. slashdot.org/comments.pl?sid=314547&cid=20819199
    5. Re:It was a nickname by Arclight17 · · Score: 1

      The LESBIAN agenda!
      The Gay agenda deals with taking over the world, enslaving the religious right, and other sundry plans.

      The Lesbian agenda deals with assless wedding gowns, flannel, and naming things in a feminist fashion.

      :-)

      --
      All men can fly, but sadly, only in one direction--Down.
    6. Re:It was a nickname by Fred+Ferrigno · · Score: 1

      Wow, that's actually cooler. 'Cause it references Lucy Lawless, the person, rather than Xena the character. Lucy Lawless probably is the only person alive and perhaps the online person ever to have a moon named after her.

    7. Re:It was a nickname by The+Fun+Guy · · Score: 1

      Plus the Christians would go nuts, seeing it as a sign of further support for the homosexual agenda.

      Huh? What are you talking about? Why would a reference to Xena: Warrior Princess be perceived as support for homosexuality?

      --
      The man who does not read good books has no advantage over the man who cannot read them. - Mark Twain
    8. Re:It was a nickname by jollyreaper · · Score: 1

      Plus the Christians would go nuts, seeing it as a sign of further support for the homosexual agenda. Huh? What are you talking about? Why would a reference to Xena: Warrior Princess be perceived as support for homosexuality? Perhaps because Xena and Gab were such very "close" friends? *cue wakicha-wakicha music*
      --
      Kwisatz Haderach
      Sell the spice to CHOAM
      This Mahdi took Shaddam's Throne
  19. I don't understand this 'dwarf planet not planet' by Anonymous Coward · · Score: 0

    Surely a dwarf planet is a planet, in the same way that a yellow car is a car. Maybe they meant to call Eris a "planetoid"?

  20. Ah, astronomers... by UbuntuDupe · · Score: 4, Funny

    Remember: just now they figured out which of Eris and Pluto is more massive...

    but they also know the internal density distributions of extrasolar planets that barely take up a pixel on the most powerful telescopes.

    1. Re:Ah, astronomers... by Pausanias · · Score: 1

      LOL, too true.

      With the mass of Eris and Pluto, it was a relatively high precision measurement (for astronomers anyway). For the internal density profiles of planets, it's not a direct measurement---it's modeling of the data to argue for consistency with various models. So, to put it more accurately, they just measured the masses of Eris/Pluto correctly; but for the extrasolar planets, they considered various models consistent with the data and showed which one is most likely.

      Generally the public doesn't know/care about that particular distinction. And that's good for funding.

    2. Re:Ah, astronomers... by bdeclerc · · Score: 3, Informative

      Actually, while the measurement of the extrasolar planets with "known" masses is likely to be considerably less precise than the mass measurements of Eris & Pluto, it is by no means as "based on models" as you imply.

      Those planets for which actual density has been determined are in a special class (or at least, special from our viewpoint):
      These are planets which (a) pass in front of their star as seen from earth, thereby causing a slight dimming of the starlight seen from here, and (b) have sufficient mass to cause a measurable red/blueshift in the spectrum of their parent star.

      The dimming of the light gives us their apparent diameter relative to their parent star, the duration of the dimming gives us a pretty accurate idea of the diameter of the star, the red/blueshift gives us their mass relative to their parent star and the orbital period gives us, to a considerable degree of accuracy, the mass of their parent star.

      These four parameters are actual measurements, so since we can derive the actual mass & diameter of the planet from these four parameters quite easily, the average density value we derive is as close to a direct measurement as we'll get.

      For planets which do not eclips their star as seen from earth, only lower limits to their mass can be determined (so the planet has to be "at least x earth masses") and even those do indeed depend on stellar modelling to determine the mass of the star, but since without the eclipses, there is currently no way to determine the diameter of said planet, there is no realistic way to determine the actual density of the planet anyway.

    3. Re:Ah, astronomers... by bryan1945 · · Score: 1

      I'm not a big astronomy guy, but could this be because extra-solar planets are the current "sexy" thing to look at? It seems that the "sexier" stuff gets more funding, ergo, let's half-guess some crap up about Alpha Unicron?

      --
      Vote monkeys into Congress. They are cheaper and more trustworthy.
    4. Re:Ah, astronomers... by Tom+Womack · · Score: 1

      This was just a scheduling problem; to figure out the orbit of Dysnomia, you need to take several exposures at different times using a telescope facility capable of resolving Eris and Dysnomia. Which means either the Keck laser guide-star system, or Hubble. Each of which has a queue of astronomers reaching three times round the block who want to use them; and the queueing systems are designed for 'I want to spend a night taking spectra of this radio-galaxy' rather than 'I need pictures which take a five minute exposure, but I'd like one every 30 hours for a month'.

      Also, it takes ages to get papers written and published; the Hubble pictures of Dysnomia were from August 2006 and the paper (in Science, a journal which is really quite quick to publish) came out yesterday.

  21. Pluto had remained a planet by nurb432 · · Score: 0, Flamebait

    It still is. And anyone who disagrees is an idiot.

    --
    ---- Booth was a patriot ----
    1. Re:Pluto had remained a planet by philpalm · · Score: 1

      Biased American astronomers prefer to claim Pluto as a planet(since it was an American discovery). Lazy students prefer to remember less names. Slash dot prefers to keep putting salt in The Wounds of those astronomers who preferred to keep Pluto as a planet.

      Now calling me an idiot would make you feel better go ahead. At least I am not a Rocket scientist....

    2. Re:Pluto had remained a planet by nurb432 · · Score: 1

      If you believe it is not a planet, then you have earned the title. If you accept that it IS a planet, then no 'name calling' will apply.

      --
      ---- Booth was a patriot ----
  22. Pluto never should have been a planet by theWrkncacnter · · Score: 1

    It's funny how people get so worked up about Pluto not being a planet. The fact is that it should have never been a planet in the first place. Scientists did a similar thing back in the 1800s when the decided not to call all of the asteroids between Jupiter and Mars planets. If we kept calling Pluto a planet, then we'd have to add all the other Kuiper belt objects. There's a very good Scientific American article here that explains the whole thing. If you're still crying about Pluto not being a planet you should probably read it.

    --
    -1 (Troll) is antihammer
    1. Re:Pluto never should have been a planet by khallow · · Score: 1

      I don't see the dust settled on this issue. Looks to me like the IAU will have to revisit this issue at the next meeting in 2009 (especially since the definition isn't well-defined). Who knows what a planet will be after that? And what's your reasoning for claiming Pluto "should" have never been a planet? In the case of the asteroids, four were found in quick succession. So it was known almost from the begining that there were several asteroids. More were found around thirty years later. In comparison, Pluto was unique from the 30's until the 90's. So I don't think your accusation is fair to the original decision to make Pluto a planet.

      I don't see a strong reason to keep Pluto a planet given that there's probably a large group of objects larger than it, that we haven't discovered yet. But the IAU decision was hasty and sloppy and the decision will certainly be revisited.
    2. Re:Pluto never should have been a planet by mdwh2 · · Score: 1

      Whether or not the asteroids we found quickly in succession or not is beside the point - the first few were still labelled planets for about 50 years, before they decided to reclassify them.

    3. Re:Pluto never should have been a planet by Bongo+Bill · · Score: 2, Insightful

      This is the reason that people think Pluto should be a planet:

      Did you learn it before you were ten years old? If yes, it can not ever change.

      --
      ...but is it art?
    4. Re:Pluto never should have been a planet by Anonymous Coward · · Score: 0

      If I'm crying, how can I read the article, you insensitive clod?

    5. Re:Pluto never should have been a planet by Ian+Alanai · · Score: 1

      Pluto shouldn't have been declared a planet in the first place because it is tiny and its orbit crosses that of Neptune. It is a moon-in-waiting.

      As for the IAU decision, yah, it was a bit ad-hoc. I agree it will be revised, it needs to be. But Pluto will not be a planet again.

      BTW I do like the reasoning in the Scientific American article.

      --
      Whichever way you look at it, it's true. I'm not.
    6. Re:Pluto never should have been a planet by Hektor_Troy · · Score: 1

      Did you learn it before you were ten years old? If yes, it can not ever change.

      This certainly explains oddities like Santa Claus, the Tooth Fairy, religion, the Easter Bunny and all that other crud.
      --
      We do not live in the 21st century. We live in the 20 second century.
    7. Re:Pluto never should have been a planet by khallow · · Score: 1
      Pluto never will be a moon of Neptune unless something knocks it loose. It's locked in a stable orbital resonance with Neptune.

      But Pluto will not be a planet again.

      Unless dwarf planets become a subcategory of planets which is where we should have been heading. After all, what's the point of calling something a "dwarf planet" and then having to say each time that that doesn't mean it is a real "planet".
    8. Re:Pluto never should have been a planet by khallow · · Score: 1

      And as I pointed out, Pluto was different. We didn't know about other members of the category for many decades.

    9. Re:Pluto never should have been a planet by Ian+Alanai · · Score: 1

      I agree that "dwarf planet" is stupid. Pluto, Eris and the rest should just be called Kuiper Belt Objects. They are not and should not be categorised (sub or otherwise) with "planets".

      I mean, what, precisely does Pluto have in common with any of the planets? Size? Orbital inclination? Orbital shape? Composition?

      Pluto was accidentally discovered, on the basic of faulty calculations, masquerading as a planet. It was only classified as a planet because almost nothing was know about it at the time. It is a bloody binary system to start with. It is smaller than 7 of the planetary moons. It is made of ice. Its orbit is also inclined so far off the elliptic that never actually crosses Neptune's orbital track. In fact, given Pluto's composition and orbit (inclined and elliptical) you could make a good case for calling it a comet.

      --
      Whichever way you look at it, it's true. I'm not.
  23. I'm no astrophysicist... by Mordok-DestroyerOfWo · · Score: 1

    But I've always defined a planet as a solid body whose gravitational field was sufficient to force it into a spherical shape and strong enough to maintain some sort of atmosphere. I suppose that would kick Mercury out of the planet club as well, but we would welcome Titan with open arms.

    --
    "Never let your sense of morals prevent you from doing what is right" - Salvor Hardin
    1. Re:I'm no astrophysicist... by ZombieWomble · · Score: 1
      Any definition based on atmosphere isn't very useful, as the ability of a planet to retain an atmosphere is not determined solely by its own properties, but also by its distance from the sun. Indeed, by your definition Pluto and a few other moons are planets while Mercury is not, as although Mercury is significantly larger, it is also significantly hotter.

  24. music video by the_mighty_$ · · Score: 1

    Poor lonely Pluto;
    No one loves you now but me.

    You actually aren't alone. These guys were so moved with affection for Pluto that they created a music video. Rock on, Pluto!

    --
    VI VI VI - the editor of the beast!
    1. Re:music video by EvanED · · Score: 1

      There's also Jonathan Coulton's I'm Your Moon, a love song from Charon to Pluto.

      Watch this video for his introduction to the song, but you can download (for free -- CC license -- or buy) an MP3 here, since the video cuts out briefly every couple minutes.

  25. Pluto and its 'Moon' - Really A Broken Ball of Ice by rogerborn · · Score: 1

    Consider the image of a hard packed snowball, broken into two unequal parts.

    So goes the latest theory about this 'planet' Its size, if the two pieces were weighed together,
    would make it a considerable planet in its own right. But if it is broken in two because it is
    made of mostly ice and lighter elements, would we consider it to be a planet at all or just
    another large body out in the Ort Cloud?

    "Sorry. No Refunds."

  26. Everyone? by KenAndCorey · · Score: 2, Informative

    Everyone still considered Pluto a planet then [in 2005]

    What are you talking about? I haven't considered it a planet since I took astronomy in the early 90's. Of course the public didn't have a clue, but a lot of astronomers knew Pluto shouldn't be considered a (regular) planet.

    1. Re:Everyone? by Anonymous Coward · · Score: 0

      So... 99.5% of the population considered Pluto a planet? Definition in a language is determined by most conventionally accepted meaning, not that which is handed down from "authority".

    2. Re:Everyone? by Abcd1234 · · Score: 1

      Uhuh... yeah, and 99.5% of the public probably think a Koala is a bear, but that doesn't make it any more true.

      What you're describing is democratically defined knowledge. You must *love* Wikipedia.

    3. Re:Everyone? by KudyardRipling · · Score: 1

      I'm a Gen-Xer (who never sported a mouth-gasket goatee to hide a double chin or be hip/cool/in-vogue/etc.) born in the mid 1960's and was so oohed-and-ahhed over the space program. I acquired my first astronomy book when I was five. I took note of the planetary orbits. Why is Pluto's orbit not like the other planets? I knew that was trouble right there. I remember that Pluto was 'a bit smaller than Mars' (with the obligatory question mark after every figure in every book). As telescopes improved, it got smaller and smaller like the Incredible Shrinking Woman. Now fixed at 2300+ km, it would make a swell moon for any giant planet (e.g. Triton).

      Get over it, people. Planets do not have civil rights (I can here the sneers about how morbidly obese humans cause mascon dips in satellite orbits or effect gravitational lensing). Does the reclassification of Pluto raise your taxes? Does the reclassification of Pluto raise your auto insurance rates? Does the reclassification of Pluto cause your home to be ransacked by secret police? [insert rhetorical answer here]

      # mv pluto_planet_love_affair /dev/null

      --
      Submission as evidence constitutes plaintiff and/or prosecutorial misconduct.
  27. Mistaken assumption by aafiske · · Score: 4, Interesting

    I think the mistake in the logic here is assuming that Pluto was kept a planet because it had a certain mass, or orbit, or whatever. Pluto was kept a planet because of tradition, in essence. If it were found today, I don't think it would be considered one. So no opening of the floodgates for every hunk of rock that has some number that measures larger than Pluto.

    1. Re:Mistaken assumption by ZombieWomble · · Score: 1

      While the basic gist of your comment is correct, I think the mistake in your logic is assuming Pluto is still a planet.

  28. uhhhhhhh by dreemkill · · Score: 1

    yeah, uhh..since when did size determine if something is a planet?

    --
    dreemkill.
    1. Re:uhhhhhhh by dltaylor · · Score: 2, Interesting

      Ceres was a "planet", or, at least, called one (1802), long before Tombaugh found Pluto (1930). So were some of the other asteroids. When they figured out it was just one instance of a large class of similar objects (asteroids), they changed its designation. Pluto/Charon (with the twins) has now been demonstrated as an instance of another large class of similar objects (Kuiper Belt Objects - KBO) that just happens to orbit noticeably closer than its siblings.

      To the ancient Greeks a "planet" was any apparent celestial object, other than Earth's moon, that moved noticeably against the background stars. Working with just the unaided eye, Pluto doesn't count, because it cannot be seen. Working with telescopes, we've got effectively uncountable numbers of asteroids, KBOs, and galaxies that move against a galactic star field that is itself composed of relatively moving objects.

      Between the time of Neptune's discovery and the asteroids' reclassification there were more than 10 planets, then back to 8. Pluto was prematurely added so we called it 9, then reclassified it, so now we're back to 8. Many objects have been mistakenly and/or prematurely classified (humans as an intelligent species, as opposed to the small number of intelligent individual humans, for example), then the classifications adjusted upon reexamination of the evidence or discovery of new evidence.

      We throw labels at things. Sometimes they stick, sometimes they don't. Get over it.

  29. Dwarf Planet is so Politically Incorrect... by sconeu · · Score: 4, Funny

    Pluto and Eris prefer the term "Gravitationally Challenged".

    --
    General Relativity: Space-time tells matter where to go; Matter tells space-time what shape to be.
    1. Re:Dwarf Planet is so Politically Incorrect... by Doug+Neal · · Score: 1

      Eh, get with the times, "... challenged" is so 20th century. Nowadays they prefer the term "differently gravitated".

  30. Correction & Addendum by Pfhorrest · · Score: 1

    - Amongst non-stars, bodies which are of sufficient mass to be approximately round (major planets) versus those which are not (minor planets or asteroids) Er, scratch that "asteroids" bit, that was written in error.

    Also, it dawns on me that all non-stars are planets (though not planets simpliciter) by this system of classification, so, this line merely distinguishes between major and minor planets.

    On that note, it would probably also be useful to distinguish first between bodies at rest upon other bodies (like me and this computer) versus bodies in freefall (like all the forgoing bodies), for I'm uncomfortable with myself being classified as either a star or a planet. We could call the latter "celestial" bodies and the former, say, "terrestrial".
    --
    -Forrest Cameranesi, Geek of all Trades
    "I am Sam. Sam I am. I do not like trolls, flames, or spam."
    1. Re:Correction & Addendum by Anonymous Coward · · Score: 0

      "Also, it dawns on me that all non-stars are planets..."

      Taken literally, that should really only dawn on you if the non-star in question is rotating, near a star, and you are on it.

      --AC

  31. My Very Excellent Mother Just Served Us NOTHING! by Tatarize · · Score: 1

    Yeah, but Pluto got voted out... so now.

    My Very Excellent Mother Just Served Us NOTHING!

    You know, Pluto had a good thing going until these stupid other transneptunian objects started to to clutter sky and make people turn on poor little Pluto. It's like being able exploit a flaw in a game. It works great for a while, but then a bunch of people do it and you're screwed.

    --

    It is no longer uncommon to be uncommon.
  32. Had to be said... by schattenteufel · · Score: 1

    "Mass of Dwarf Planet Eris 27% Greater than Pluto... surely Eris would be considered the 10th planet." If that's all it took, then my ex-girlfriend would be classified as a planet as well!

    --
    Schatten Teufel
    There is nothing "Common" about Sense
    1. Re:Had to be said... by RedElf · · Score: 1

      If that's all it took, then my ex-girlfriend would be classified as a planet as well! That's some, uh, interesting taste you have in women there.
      --
      You know, I have one simple request. And that is to have sharks with frickin' laser beams attached to their heads!
  33. Have we learned nothing? by halovaa · · Score: 1

    Wasn't the Trojan War started because she wasn't invited to a party? And now, not only is she not invited to join the planets...but we're calling her FAT?

  34. The not-so-littlest dwarf planet by ackthpt · · Score: 1

    "It's barely enormous!"
    "It's merely huge!"

    --

    A feeling of having made the same mistake before: Deja Foobar
    1. Re:The not-so-littlest dwarf planet by Saint+Fnordius · · Score: 1

      27% more, eh? Are you sure it isn't really 23%?

      Still, nobody, nobody should say to Eris, "say, you been puttin' on mass?"...

  35. Where is this "clean" ontology you speak of? by Anonymous Coward · · Score: 0

    So are you saying that Pluto will never clear it's orbit path? Do we know that, or do we change Pluto's designation when it does (in the distant future). And what if we find a planetary system that has two massive planets on the same or near orbit path but on opposite sides of their star. Are they not planets because they havn't cleared their orbit path? And of what significance is this definition of "cleared" aside from it's unnerving likeness to the sphincter it was pulled from?

    I'd also love to hear you try to articulate how these very different properties you speak of actually mark some significant change in characteristics greater than that of any other two objects you would call planets.

    Why use a convoluted ontology when a simple one would suffice?

    1. Re:Where is this "clean" ontology you speak of? by CorSci81 · · Score: 4, Informative

      Pluto won't clear its orbital path in the lifetime of the sun for a few reasons. The Kuiper Belt (where Pluto resides) is a very excited region of the solar system in terms of orbital eccentricities and inclications, which results in a very high mean impact velocity between objects out there. This means impacts tend to be destructive rather than letting anything grow larger. Additionally the number of particles in the Kuiper belt is sufficiently small impacts are fairly rare. Basically, the Kuiper Belt never became a planet for much the same reason the asteroid belt hasn't.

      Regarding the two planets bit, that's a highly unstable orbital configuration. If they orbited a common center of mass (like the Earth and moon) it would be feasible, but then we'd just call them a twin planetary system, or the smaller of the two would be considered a moon.

    2. Re:Where is this "clean" ontology you speak of? by Anonymous Coward · · Score: 0

      So are you saying that Pluto will never clear it's orbit path? Do we know that, or do we change Pluto's designation when it does (in the distant future).

      It won't, but I would agree to a change in classification when it does.

      And what if we find a planetary system that has two massive planets on the same or near orbit path but on opposite sides of their star.

      If they aren't constantly being hit by stationary asteroids, they have cleared their path. So yes, they would both be planets.

      I'd also love to hear you try to articulate how these very different properties you speak of actually mark some significant change in characteristics greater than that of any other two objects you would call planets.

      For one thing, they wouldn't be constantly hit by massive stationary asteroids. This is pretty important, since planets have classically been understood to be the result of collecting stray solar matter. Earth, for instance, has been classified as a "proto-planet" or "planetoid" while it was collecting nearby matter. This is specifically because its interactions with nearby objects were dominant in that phase of the planet's development. What's the point of calling a particularly large asteroid a planet, especially when it's surrounded by a ring of smaller asteroids with thousands/millions of times its mass? The asteroid belt in question seems to be the dominant object of which this pseudo-planet is just a small part.

    3. Re:Where is this "clean" ontology you speak of? by khallow · · Score: 1

      Pluto won't clear its orbital path in the lifetime of the sun for a few reasons.

      The key reason it won't clear it's orbital path is because the term is undefined. Yes, I know about the paper from which the term was borrowed. I also know that the IAU didn't adopt that definition.

  36. Apparently... by Loconut1389 · · Score: 1

    ...for Astronomers, Size Matters.

  37. Re:GOAT by Anonymous Coward · · Score: 1, Funny

    That's not Eris or Pluto...it appears to be a black hole.

  38. spoiler alert! by kaizokuace · · Score: 2, Funny

    Eris dies.

    --
    Balderdash!
    1. Re:spoiler alert! by Anonymous Coward · · Score: 0

      I can't believe I actually laughed at that.

      Well played, sir.

  39. Re:That planet is for gays. by BakaHoushi · · Score: 1

    I find this to be highly illogical and foolish. How can you say that with a planet nearby called URANUS? The joke is as old as the name. Clearly, you are either clueless to astronomy, or a troll.

    Personally, Pluto shouldn't be so down. It has confirmed land. Jupiter, Saturn, Uranus (or as it will later be known, Urectum), (and possibly Neptune) do not. "Hey Jupiter, I bet you can't wait to have someone land on you and plant a flag... oh, wait, that's right. YOU CAN'T!" "Hey, Saturn, look what I can do. Notice all this SOLID I can do, hmm? Why don't you give it a try sometime!"

  40. Disinformation by bar-agent · · Score: 1

    27% Greater than Pluto

    I don't believe any statistic about a planetoid named after the Goddess of Disinformation.

    "There's lies, damn lies, and statistics...and then there's Discordians."

    --
    i'd hit it so hard, if you pulled me out you'd be the king of britain [bash.org]
  41. Eris... by SenorAmor · · Score: 1

    Eris would *not* be considered the 10th planet.

    And don't call me Shirley.

  42. Solution... Like Tea by Anonymous Coward · · Score: 0

    Just use the same naming convention for planets as they use for tea.

    Super Fine Tippy Golden Flowery Orange Planets = your major plants
    Fine Tippy Golden Flowery Orange Plants = minor plants

    and so on down the scale to just

    Orange Planets = all the little parts around the solar system

  43. 27% more massive! by tomatoguy · · Score: 1


    thatsalottamassive!

  44. Re:Pluto and its 'Moon' - Really A Broken Ball of by jae471 · · Score: 1
    Actually, taken together, Pluto + Charon (~2x10^22 kg) is less than the mass of the moon (~7x10^22 kg).

    Also, the combined mass is not sufficient to clear its orbit. (Otherwise it would have done so already.)

  45. Astrology revamp? by Manos_Of_Fate · · Score: 1

    So what happens when Eris is in my sign? WTFBBQ!

    --
    Isn't enough that I ruined a pony, making a gift for you?
    1. Re:Astrology revamp? by BoothbyTCD · · Score: 1

      Though I know you are being intentionally silly, Eris has a highly inclined orbit and is very rarely in any traditional zodiac sign.

      --
      snig
  46. Not disappointed - thank you by Weaselmancer · · Score: 1

    I came in here looking for this exact comment, and am not disappointed to see that One Of Us managed it on the third post.

    Also funny that you are modded to 5. Fnord.

    --
    Weaselmancer
    rediculous.
  47. Gah, cut it out by Estanislao+Mart�nez · · Score: 2, Insightful

    I think we need to have our system of classifications able to accurately distinguish between: [classification snipped]

    Why? The actual physical and astronomical facts about the matter, given our contemporary understanding of astronomy, do not depend on such a classification at all. The classification of the celestial objects is not a matter of convenience, not of fact. No astronomical fact follows independently from the "fact" that body X is classified as a Y in your scheme. That is, the only facts that follow about body X are the very same facts that the classification requires for it to be an X; when you gather all the facts that you need to classify X as a Y, the fact that X is a Y does not allow you to infer further facts about it.

    Because, of course, there are no physical or astronomical law hinges on whether an object is a star, planet or moon; they're just big blobs of matter in various states, of various shapes, moving at various velocities relative to each other, and exerting all of the usual forces that they exert in virtue of being the aggregates of the stuff they are made out of.

    1. Re:Gah, cut it out by Pfhorrest · · Score: 4, Interesting

      You are of course completely right that naming conventions per se tell us nothing about the physical universe. However, good taxonomies and naming conventions will allow someone to tell a lot about the physical attributes of something which has previously been examined and classified by someone else just be hearing it's name. For example, "lion" and "tiger" are two names which refer to very similar objects, but you wouldn't know that just by their names. Panthea leo and Panthera tigris, on the other hand, let you know that these are both subtypes of some object class Panthera, and if you know what that entails, then you'll know a lot about both of those objects. If I overheard that there's a wild Fubar on the loose, I'd have no idea what that was until it was explained to me (though by context I could guess that it's some sort of animal); however, if I overheard that a Panthera fubaris had escaped, while still not knowing what exactly that was, I'd know it was some sort of large carnivorous feline, and thus just by convenient naming, I'd be able to learn (and communicate) new information much more quickly.

      --
      -Forrest Cameranesi, Geek of all Trades
      "I am Sam. Sam I am. I do not like trolls, flames, or spam."
    2. Re:Gah, cut it out by Estanislao+Mart�nez · · Score: 1

      However, good taxonomies and naming conventions will allow someone to tell a lot about the physical attributes of something which has previously been examined and classified by someone else just be hearing it's name.

      Examined and classified... for what purpose? Why are you trying to erect a grand classificatory scheme without tying it to some specific task that compels you to do so? Why do you propose such a thing as the "right" or "best" way of classifying celestial objects?

      For example, "lion" and "tiger" are two names which refer to very similar objects, but you wouldn't know that just by their names. Panthea leo and Panthera tigris, on the other hand, let you know that these are both subtypes of some object class Panthera, and if you know what that entails, then you'll know a lot about both of those objects.

      The only thing that entails is that members of both species share a common ancestor, that this common ancestor is relatively more distant to tigers than the common ancestor to all tigers is (genus is above species), yet closer than the common ancestor for all felines or that of all mammals. It entails absolutely nothing more. Nothing about the phenotypes or the genotypes of the species follows from that, nor anything about how recently they diverged.

      [...] however, if I overheard that a Panthera fubaris had escaped, while still not knowing what exactly that was, I'd know it was some sort of large carnivorous feline

      Nope, you would not know that the animal in question was large or carnivorous. Those would be nothing more than a good guess.

    3. Re:Gah, cut it out by Estanislao+Mart�nez · · Score: 1

      Nope, you would not know that the animal in question was large or carnivorous. Those would be nothing more than a good guess.

      I should have mentioned something: the fact that those would be good guesses, given the classification, is a completely contingent fact. Nothing about the classification itself makes it more likely for a panthera to be large or carnivorous than otherwise.

    4. Re:Gah, cut it out by Cadallin · · Score: 1
      Do what now? The only herbivores in the Carnivora are the Pandas. Genetic studies have shown that Pandas are closely related to bears, but they're given their own genus on the basis of their herbivorous habit. Everything else is omnivorous, and simultaneously a dangerous predator (bears), or carnivorous. A quasi-exception to that are some of the species that can live off of plant material exclusively (most of the Canines), but they're best characterized as omnivores, they'll preferentially take meat when they can get it, and accept plants if they can't. A herbivorous derivative of the Felis genus would be grounds for a new genus in all probability. As it would require major changes to Feline body chemistry. Felines are extremely deficient in their ability to metabolically process sugar, which makes a herbivorous diet dangerous for them.

      You seem to be completely ignorant of Phylogenetics, which is being used to reorganize taxonomy, on the basis of much more sound principles, like genetics and biochemistry, as more data becomes available. Sometimes major surprises come up, and large groups get shifted around. A well publicized recent change was the discovery that order Aves, belonged in Superorder Saurischia as a sister group to the Therapoda. Which is to say that birds were found to be dinosaurs and a sister group of the Theropods.

  48. Reminder on the history of planethood by frankie · · Score: 1

    First, a quick response to your proposal: LOTS of things have moons. There are quite a few non-round asteroids (not big enough to gravitationally collapse) that have moons. In general, if any of us here in the peanut gallery have a proposed definition that sounds even vaguely plausible, it's a good bet that the professional astronomers have not only thought of it years ago, but also figured out solid reasons why it wouldn't work.

    Speaking of asteroids, I'd like to remind everyone that for most of the 19th century, there were over 10 officially recognized planets. In addition to the classical planets Mercury, Venus, Earth, Mars, Jupiter and Saturn, they had Uranus (1781), Ceres (1801), Pallas (1802), Juno (1804), Vesta (1807), and finally Neptune (1846). The same improvements in optics that led to the discovery of Neptune also pointed out several other planetary bodies. Then dozens. Then hundreds, all coorbital with the four between Mars and Jupiter, forming a vast ... belt, of sorts.

    You can guess what happened next (hint: you weren't told to memorize 13 planets back in grade school). The relevance of this tale to Pluto is left as an exercise for the reader.

  49. SHHHHH..... by IHC+Navistar · · Score: 1

    Don't tell the Scientologists: Xenu lives on Eris.

    Pass it on.

    --
    Knowing Google's lust for data collection, the Soviet Union is still alive and well inside the psyche of Sergey Brin....
  50. Re:Pluto and its 'Moon' - Really A Broken Ball of by rogerborn · · Score: 1

    You are correct. The 'planets' out that far are rather small. But both Pluto and Charon combined are still bigger than Eris, and any others yet to be discovered, in descending order of size. It was once thought that there could be massive planets lurking in the Ort Cloud, but Pluto/Charon and Eris may be the biggest (and only) ones there. It would be interesting to know how or what caused Pluto/Charon to break apart. There may be hundreds of smaller parts surrounding them both, as they orbit each other. Time will tell.

    "If it doesn't work out the way you want it to, it will work out the way its supposed to be."

  51. Pluto is still a big rock by patio11 · · Score: 1

    And for definition of the word "flat" that means "well, sort of spheroid", the world is indeed flat. This whole stupid squabble isn't about Pluto, its about the word "planet". You know what? I don't care what planet means. I don't care if you can consistently differentiate moons from planets or not. It will never, ever, ever impact my life. When my kid takes astronomy in school I will tell him "Son, here are the list of nine really big rocks which you need to learn to get to the next grade. Get started." Because that is all a planet is -- a big rock, which is special because we traditionally say it is. Whats the difference between a mountain and a hill? The mountain is labeled Mountain on the map, not hill -- its a big important rock, not like that everyday garden variety rock next door.

    Astronomy, by the way, is a waste of classtime for science. Its studied purely for aesthetic reasons, always has been ("Ahh, the Heavens, they're so pretty the gods must have made them... and look, they obey convenient mathematical properties too!"), but you can find just as much aesthetic beauty in biology or chemistry or geology for that matter, and any one of these actually has practical applications. Not that any kid is likely to ever need to know the difference between metamorphic and igneous rock, but they will at some point come into physical contact with both of them, which is a heck of a lot more than you can say about Pluto/Eris. Astronomy as I was taught it was "Literature enjoyment of sci-fi novels", where they teach you to disregard everything you will ever learn about physics, math, and economics and pretend that you will, in your lifetime, see thriving and productive human colonies on celestial bodies which we know to be big, barren, worthless rocks.

  52. What do you call "mass of Pluto" ? by Anonymous Coward · · Score: 0


    Is it supposed to mean, "The mass of the Pluto/Charo double planet formerly referred as "Pluto"", or "The mass of what is now called "Pluto", whichi is a part of the Pluto/Charo double planet" ?


    The difference is slight, true : 13%, as far as I remember. However is is rather hard these days to know exactly what people mean when they say just "Pluto" :-(

  53. Re:That planet is for gays. by Jehosephat2k · · Score: 1

    "The joke is as old as the name. "

    No, it's as old as the English Language.

  54. Where are we going? by Tmack · · Score: 1
    Planet Ten!!

    When?

    Real Soon!!!

    th

    --
    Support TBI Research: http://www.raisinhope.org
  55. Orbital bassassery! by Saint+Fnordius · · Score: 1

    So to be a planet, you have to be the baddest badass in your orbit, and clear your path of all those other upstarts in your way? Pluto and Eris, being so far out, will probably never make it then since their orbits are so huge that some punk-ass twerp will always be able to settle in and make itself at home. It will take centuries until Pluto or Eris manages to swing around and pulverise the little creep. The distance between Pluto and Eris is also sufficient enough that they may never cross paths and enter a deathmatch. Things get weird once you get that far out from the star.

  56. Re:That planet is for gays. by Ihlosi · · Score: 3, Funny
    "Hey Jupiter, I bet you can't wait to have someone land on you and plant a flag... oh, wait, that's right. YOU CAN'T!"



    "I've got moons that are bigger than you."

  57. What difference... by Dirtside · · Score: 1

    What difference does it make whether there are nine things we call "planets," or eight, or ten, or a hundred, or a thousand? I suppose "planet" is a less special term if there's a lot of them, but we already know there are hundreds out there already; so what if there's a hundred in our solar system, or only fifty, or whatever. Seriously, what difference does it make to anything?

    The physical and orbital characteristics of Pluto and Eris will remain the same regardless of whether we call them planets or minor planets or dwarf planets.

    --
    "Destroy science and religion. Science would re-emerge exactly the same; but not religion." - Penn Jillette, paraphrased
  58. Planet X is the issue here by Anonymous Coward · · Score: 0
    What nobody mentioned here till now, is Planet X from Stitchin.

    There a loads of resources about this on the internet. Do a google search on "Planet X" and you get 75,800,000 Results.

    This stuff is too sensitive, so I must post it anonymously.

  59. Pluto's Charon by NotmyNick · · Score: 1

    Lucy Lawless probably is the only person alive and perhaps the online person ever to have a moon named after her.
    Actually, James Christy named Charon (and established the sh pronunciation) in honor of his wife Charlene. I don't know if she spends any time online however.
    --
    Notmysig
    1. Re:Pluto's Charon by Anonymous Coward · · Score: 0

      Wow, how much trouble could a husband be in for comparing their wife to the ferryman of the underworld?!

    2. Re:Pluto's Charon by Cro+Magnon · · Score: 1

      Wow, how much trouble could a husband be in for comparing their wife to the ferryman of the underworld?!


      Yeah, she could make his life hell for that!
      --
      Slow down, cowboy! It has been 4 hours since you last posted. You must wait another few hours.
  60. I thought that was why they were to be in by Anonymous Coward · · Score: 0

    Pluto "must remain a planet" because a 'merkin discovered it.

    If we allow Eris and Pluto in, will we have planets defined as "this list of 10 planets" which isn't all that useful around any other sun and a bit of a tautology or "bodies of type, plus pluto and possibly Eris" which is a decent definition with one or two silly additions.

  61. Guxtav Holst was right by Anonymous Coward · · Score: 0

    The definition of a planet is whether there is a movement named after it in Holst's Planet Suite.
    He never wrote one for Pluto.

  62. Let me get this straight by jshriverWVU · · Score: 1
    It goes around our sun? Check
    It's somewhat large? Check
    It even has it's own moon? Check

    So why is this not considered a planet? I never understood why we demoted Pluto.

  63. Classification by Cro+Magnon · · Score: 1

    If you really want to get picky on classification, we probably shouldn't put the outer planets in the same category with Earth. Earth & Pluto are more alike than Earth & Uranus. Earth & Pluto are both round, solid masses of various minerals. Uranus and the other outer planets are just enormous masses of gas with no solid surface and no rocky minerals.

    --
    Slow down, cowboy! It has been 4 hours since you last posted. You must wait another few hours.
  64. Mondas is the 10th, silly. by Quatermass · · Score: 1

    "surely Eris would be considered the 10th planet."

    No, no, no.... Mondas is the Solar Systems 10th Planet.

    Mondas was Earth's twin planet, identical down to even the size and shapes of its continents. Millions of years ago, it was the tenth planet of the Solar System, until somehow it drifted out of its orbit and journeyed into deep space.

    Ask any (classic) Dr. Who Fan... ;-)

    http://en.wikipedia.org/wiki/Mondas_(Doctor_Who)

    --
    Stuart http://stuarthalliday.com/
  65. Re:That planet is for gays. by BakaHoushi · · Score: 1

    "Hey, it's not your size that matters, it's how you orbit, baby."

  66. Activate interlocks... by Saberwind · · Score: 1

    Now we can send our intrepid space explorers there to protect the planet from King Zarkon.

  67. Pluto and Eris Are Both Planets by laurele · · Score: 1

    This discovery changes nothing regarding Pluto's status. Mike "Pluto is dead" Brown is wrong in his non sequitur argument when he says "this is the last chance that Pluto had." Many in the astronomy community still consider Pluto a planet. There is hardly consensus otherwise, as Brown wants people to think. Eris being larger does nothing to negate the argument that Pluto is the solar system's ninth planet and Eris its tenth planet. Why the tenth planet cannot be larger than the ninth, in Brown's view, is beyond understanding. How can the status of another object, rather than its own characteristics, define what Pluto is? The truth is astronomers remain very divided on this issue, and the debate is not over.

  68. North Equatorial Belt by Latent+Heat · · Score: 1
    Most men as they approach sagging middle age wear their belt low over the hips with the mid section draped over the top of the belt. A number of very old men somehow manage to wear the belt draped over the top. When men make the transition between these modes is not known to science.

    I was at a classical music concert on campus when beforehand some young women were having an animated conversation about over-the-top-belt-wearing men and how ridiculous they looked. Normally one doesn't interrupt the fun conversation of strangers, but I couldn't stop myself then. At that time, Clyde Tombaugh was nearing age 100 and his picture would show up in Sky and Telescope. Planetary scientists talk about a North Equatorial Belt and a South Equatorial Belt (of Jupiter), I told them that Clyde Tombaugh, discoverer of Pluto, was definitely a North Equatorial Belt kind of guy.

  69. Re:That planet is for gays. by Alsee · · Score: 1

    "Oh yeah? Well at least I'm not made out of fart."

    -

    --
    - - You can't take something off the Internet! That's like trying to take pee out of a swimming pool.
  70. Re:Pluto and its 'Moon' - Really A Broken Ball of by frankie · · Score: 1

    Pluto and Charon combined are still bigger than Eris
    No they aren't. Pluto + Charon = 1.48 x 10^22 kg, Eris = 1.66 x 10^22 kg (Dysnomia is negligible)
  71. Pluto _is_ a planet (think of the children!) by Anonymous Coward · · Score: 0

    These guys were so moved with affection for Pluto that they created a music video.

    Ever heard the song?

    Who you represent?
    I represent the smallest planet
    Attourney in this journey
    versus those who tried to ban it.
    If you don't agree
    go see interplanet Janet
    Cause the sun is star
    like Pluto is planet.

    Like the song says, Do it for the children.