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Thread: Is Pluto about to be reinstated as a planet?

  1. #61
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    "Trans" is being used to mean "beyond," although it can also be used to mean "across" (trans-continental). Perhaps extra-, supra-, or para-Neptunian would be better

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  2. #62
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    Quote Originally Posted by swampyankee View Post
    "Trans" is being used to mean "beyond," although it can also be used to mean "across" (trans-continental).
    It does go "beyond" Neptune, it also goes "across" Neptune's orbital distance.

  3. #63
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    Quote Originally Posted by Gorn View Post
    Hello. I would just like to remark how much I like the pictures I have seen of Pluto..and Charon. I get the crazy 'sense' of Pluto..being the 'planet'..and Charon..being its moon...

    Does anyone else get that?....

    I think it is a bit of 'luck' for the new horizons team etc, etc.

    Bye
    G
    There's nothing crazy about it-- Charon is a satellite of Pluto, although technically they both orbit a mutual center of gravity outside of Pluto's surface.

  4. #64
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    Quote Originally Posted by KaiYeves View Post
    There's nothing crazy about it-- Charon is a satellite of Pluto, although technically they both orbit a mutual center of gravity outside of Pluto's surface.
    With the barycenter outside of both bodies, there's nothing but convention to say that Pluto isn't a satellite of Charon though, right?

    CJSF
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  5. #65
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    Quote Originally Posted by CJSF View Post
    With the barycenter outside of both bodies, there's nothing but convention to say that Pluto isn't a satellite of Charon though, right?

    CJSF
    I guess. That's why they're sometimes called a "double system".

  6. #66
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    That's right. In most cases it's very clear which is the satellite, but in the case of Pluto and Charon, it's a bit more ambiguous. But still, Pluto is the bigger of the two.
    As above, so below

  7. #67
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    Quote Originally Posted by Jens View Post
    But still, Pluto is the bigger of the two.
    And pretty significantly so, just about twice the radius and nine times the mass.
    Conserve energy. Commute with the Hamiltonian.

  8. #68
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    Pluto should not allow itself to be reinstated on the old terms. It should demand a pay rise and a better orbit.

  9. #69
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    Quote Originally Posted by CJSF View Post
    With the barycenter outside of both bodies, there's nothing but convention to say that Pluto isn't a satellite of Charon though, right?

    CJSF

    Well, Pluto is more massive than Charon, and it is convention to say that the primary is more massive than any single satellite. It's also a formal convention that says that Pluto is a dwarf planet.

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  10. #70
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    Quote Originally Posted by swampyankee View Post
    Well, Pluto is more massive than Charon, and it is convention to say that the primary is more massive than any single satellite.
    Yes, that's what I said. Convention.

    CJSF
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  11. #71
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    Quote Originally Posted by demeter View Post
    Pluto should not allow itself to be reinstated on the old terms. It should demand a pay rise and a better orbit.
    Lol. There is no way the major planets will let it back in the group,it couldn't keep a tidy workspace, kept getting in Neptunes way and was too 'far out' most of the time.
    You're really not going to like it, the meaning of life the universe and everything is.... is.... 42!
    What??????
    is that all you have to show for 7.5 million years of work?????
    it was a tricky assignment.

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  12. #72
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    Pluto has all the qualities of a planet, but it really should be reclassified as a Kuiper belt object.

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    Quote Originally Posted by thoth II View Post
    Pluto has all the qualities of a planet, but it really should be reclassified as a Kuiper belt object.
    Well, it's a Kuiper dwarf, right? Just like Ceres is an asteroid dwarf. Both are members of those classes of minor body that are also large and round enough to be dwarf planets.

  14. #74
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    Quote Originally Posted by thoth II View Post
    Pluto has all the qualities of a planet, but it really should be reclassified as a Kuiper belt object.
    The problem with Pluto is that not everyone seems to agree on what the formal qualities of a "planet" should be. I really see no problem in it having double designation: a planet and a KBO. What is the formal definition of a KBO?

  15. #75
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    The Kuiper Belt objects are a series of minor objects existing beyond the orbit of Neptune and out to about 50 AU . Pluto and Makemake could be considered Planets except for the IAU condition that they clear their orbits of other objects. So yes, they could be planets. I think that they shouldn't be planets simply because I'd like to have them on the same footing as the rest of the KBOs: they have a similar history of formation and composition.

  16. #76
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    Quote Originally Posted by thoth II View Post
    I'd like to have them on the same footing as the rest of the KBOs: they have a similar history of formation and composition.
    I'll wait until planetary scientist have had some time to fully analyze all the great New Horizons data of Pluto before assuming that we fully understand the history of formation and composition of Pluto and other KBOs.

  17. #77
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    "I'll wait until planetary scientist have had some time to fully analyze all the great New Horizons data of Pluto before assuming that we fully understand the history of formation and composition of Pluto and other KBOs. "

    you are absolutely correct. They have a lot to learn still about Pluto and other KBOs. I just have an educated guess that they are all similar because they share similar orbits and probably were formed at the same time in history from the same cause, probably condensation in a very diffuse solar nebula cloud in that region.

  18. #78
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    KBO is something in the Kuiper Belt, so I would think just about anything short of a brown dwarf (and maybe even that) could be one.

    This brings up a new question for the IAU: how is the Kuiper Belt defined? Where does it start and end? Does a binary system have multiple analogies to the Kuiper Belt?

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  19. #79
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    I don't think so. According to some sources I read online Pluto will not be reinstated as a planet and will continue to be known as a dwarf planet.

  20. #80
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    "Don't cry Pluto, I'm not a planet either..." My son's favorite T-shirt when he was 3-4.
    Solfe

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  21. #81
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    Do you think there is some subset of IAU members that spice up papers about Pluto by reading them like Samuel L. Jackson would?

    "Oh, it another paper about the dwarf planet, Pluto."
    "PlooTow! <mumble... mumble... cuss words> Always PlooTow!"
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  22. #82
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    And a recently spied tee shirt states;

    "Dear NASA, your mom thought I was big enough.

    Sincerely Pluto."

    Yikes, serious burn from Pluto there NASA.
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  23. #83
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    there are too many KBOs similar to Pluto to recognize Pluto as a planet. What, is IAU going to name all these KBOs planets also?

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    We could just reclassify all the planets as dwarf planets.
    Mickey Mouse has grown up a cow.

  25. #85
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    Quote Originally Posted by thoth II View Post
    there are too many KBOs similar to Pluto to recognize Pluto as a planet. What, is IAU going to name all these KBOs planets also?
    Plutinos.
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  26. #86
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    Quote Originally Posted by thoth II View Post
    there are too many KBOs similar to Pluto to recognize Pluto as a planet. What, is IAU going to name all these KBOs planets also?
    The categories "planet" and "dwarf planet" have been defined; it shouldn't matter if there are two members in a class or 2000. Biologists have several genera with over a thousand species, e.g., http://www.fond4beetles.com/Bupresti...a/Agrilus.htm; objecting to a category because it's got too many members won't be looked at with much sympathy.

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  27. #87
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    One (but not the only) issue I have with the notion of "dwarf planet" in the context of our solar system is that it categorizes two broadly different object populations as the same. I get that one can do that, but I don't think it serves the astronomy community or the interested public to leave the formation and evolutionary history out of the categorization of these objects. Or maybe not leaving it out, but it is irrelevant if you already have categories like "plutino" or whatever. But as an interested layman, I don't lose sleep over it.

    CJSF
    Last edited by CJSF; 2017-Jan-29 at 03:04 AM.
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  28. #88
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    Quote Originally Posted by CJSF View Post
    One (but not the only) issue I have with the notion of "dwarf planet" in the context of our solar system is that it categorizes two broadly different object populations as the same. I get that one can do that, but I don't think it serves the astronomy community or the interested public to leave the formation and evolutionary history out of the categorization of these objects. Or maybe not leaving it out, but it is irrelevant if you already have categories like "plutino" or whatever. But as an interested layman, I don't lose sleep over it.

    CJSF
    While I happen to think the "dwarf planet" category is badly defined, and its rational worse explained, it is what the IAU decided to use. Until they come up with a better system, which should take a short period of thought followed by about ten years of discussion, they're stuck with it.

    Information about American English usage here and here. Floating point issues? Please read this before posting.

    How do things fly? This explains it all.

    Actually they can't: "Heavier-than-air flying machines are impossible." - Lord Kelvin, president, Royal Society, 1895.



  29. #89
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    Quote Originally Posted by CJSF View Post
    One (but not the only) issue I have with the notion of "dwarf planet" in the context of our solar system is that it categorizes two broadly different object populations as the same.
    You sure you didn't mean "planet" there? That sentence applies even more to planets than dwarf planets.

    Personally, they should just get rid of the category "dwarf planet" altogether. It serves absolutely no scientific purpose or even bureaucratic purpose, which is probably why they haven't added any new ones since the original 5.

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    There is something fascinating about science. One gets such wholesale returns of conjecture out of such a trifling investment of fact.
    Mark Twain, Life on the Mississippi, 1883

    I'll be honest, we're throwing science at the wall here to see what sticks.
    Cave Johnson, CEO, Aperture Science (Portal 2, 2011)

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