Well, Shit, It Looks Like Earth ISN'T a Planet Either

Discussion in 'Techforge' started by Tuckerfan, Sep 17, 2018.

  1. Tuckerfan

    Tuckerfan BMF Staff Member Moderator

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    Researchers say that if the definitions used to determine if Pluto was a planet were applied to Earth, we'd fail too.
    (bolding mine)
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  2. Amaris

    Amaris Fuzzy Logic Generator

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    Wait, wait wait wait. When did we find out these things?
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  3. Tuckerfan

    Tuckerfan BMF Staff Member Moderator

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    The moons we've known about for a while now (the first one was discovered back in the late '70s, most of the others were discovered by the Hubble), the other stuff was all the result of the New Horizons data we got.
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  4. Amaris

    Amaris Fuzzy Logic Generator

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    I must have missed that information being released. Granted, I've been very busy as of late, so I'll have to take a look. That's exciting!
  5. Tuckerfan

    Tuckerfan BMF Staff Member Moderator

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    Some of it can be found in this thread: https://wordforge.net/index.php?threads/message-from-pluto.105368/
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  6. oldfella1962

    oldfella1962 light & lethal

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    So did anybody involved think to ask the residents of Pluto how they feel about reclassification? :brood:
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  7. Dayton3

    Dayton3 Wonderful, Loving Husband & Father

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    I've been saying for years that to be a planet an object "had to clear its orbit" was ridiculous and foolish as there are no other larger bodies closer to Pluto than Earth is to the sun. (1 AU).
  8. Paladin

    Paladin Overjoyed

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    Yes, I know it means we'll probably have shitloads of planets in the Solar System eventually, but why not just define a planet as:

    1. A body massive enough to have assumed a round shape.
    2. Orbits the sun.
    3. Does not orbit another body (e.g., Venus) or, if is closely coupled to another body, is the dominant mass in the system (e.g., the Earth).

    It seems that people are trying to tailor the definition so that most of what we have formerly called planets remain so without including the (presumably) large number of Kuiper Belt objects. Well, why bother? If there are Kuiper Belt objects that look like planets, let's make 'em planets.
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  9. Dayton3

    Dayton3 Wonderful, Loving Husband & Father

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    the discovery of Pluto's moon Charon was widely considered a massive blow to Pluto's "planethood" as Charon is so large relative to Pluto that they orbit a common center of mass (above Pluto's surface) thus you could call them a "double planet system". Of course Charon's discovery also enabled scientists to discover how low mass Pluto was.

    Basically you've got a large number of what amount to big "iceteroids" in the outer solar system (Pluto, Charon, Chiron) that are such low mass that they could be considered comets that are not in cometary orbits.
  10. steve2^4

    steve2^4 Aged Meat

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    Is a tomato a fruit or vegetable? And what the hell is a platypus? Our need to classify things in narrow terms comes from our ability to recognize patterns. Sometimes it's silly.
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  11. Paladin

    Paladin Overjoyed

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    Technically, this is true of all planets with moons. The Earth and the Moon orbit a common center, it's just that the Earth is so much more massive than the Moon that the center actually falls within the Earth's volume. (The fact that bodies orbit a common center is why we can detect the wobble of stars to determine the presence of large planets orbiting them.)

    In such a situation, I'd call the more dominant of the bodies, the planet, and the lesser one(s) moons. Earth is a planet, the Moon is a moon. Pluto is a planet, Charon is a moon.
    If they've got enough mass that they have a spherical form (and they aren't closely bound to a more massive planetary body), then why not call them planets?

    Yes, I know, there's probably a lot of these out there. If it turned out that our Solar System had 57 planets, so what? Yes, that'd be a harder list to memorize and recite, but it would be accurate.
  12. Dayton3

    Dayton3 Wonderful, Loving Husband & Father

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    IIRC when Eris was discovered it provoked in part the most recent downgrade of Pluto's planetary status. Astronomers did not want dozens of more "planets" defined as such and all evidence at that time indicated (and still does) that a large number of such worlds would be inevitably discovered.

    But simply having enough gravity to pull itself into a near sphere (hydrostatic equilibrium I think its called) should probably NOT be the major standard. Because virtually every object in space more than a few dozen miles across will reach that eventually.

    Gravity thou art a heartless bitch.
  13. Paladin

    Paladin Overjoyed

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    Agreed, but to differentiate things, there has to be a real difference.

    How else but size/mass are the classical planets differentiated from every spherical asteroid floating around?

    I guess the whole "clearing the neighborhood" criteria did that, but now that seems to have fallen by the wayside.
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  14. mburtonk

    mburtonk mburtonkulous

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    It's a fruit, and a platypus is a mammal.
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  15. oldfella1962

    oldfella1962 light & lethal

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    maybe on your "planet" they are!
  16. Forbin

    Forbin Do you feel fluffy, punk?

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    I hadn't realized the fallacy of the clearing-the-orbit rule back when Pluto was axed. Now that it's been brought up, even Jupiter wouldn't count, because of its Trojan asteroids. (Actually, don't most of the planets have some Trojans?)
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  17. Tuckerfan

    Tuckerfan BMF Staff Member Moderator

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    Yeah, lots of planets do have Trojans, and the "failure to have cleared its orbit" objection was originally raised back when Pluto was downgraded. Astronomers pointed out that if there was a Jupiter-sized planet beyond the orbit of Pluto, it wouldn't have cleared its orbit by now. And, interestingly enough, that's kinda of how they're hoping to find a giant planet in our system.
  18. NAHTMMM

    NAHTMMM 2098 and counting

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    Planets is planets and art is art.

    The fight against injustice continues!
  19. Dayton3

    Dayton3 Wonderful, Loving Husband & Father

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    I think eventually they will have to factor in a spherical bodies distance from its star as being relevant to the question of planethood. Because obviously the characteristics of a planets orbit is considerably different if it orbits at 3 billion miles as opposed to 30 million.
  20. Scott Hamilton Robert E Ron Paul Lee

    Scott Hamilton Robert E Ron Paul Lee Straight Awesome

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    Man, can you imagine the contribution gturner would have made to this thread? It is right up his alley!
  21. Ancalagon

    Ancalagon outta my way Administrator Formerly Important

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  22. Tuckerfan

    Tuckerfan BMF Staff Member Moderator

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  23. Tuckerfan

    Tuckerfan BMF Staff Member Moderator

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  24. Marso

    Marso High speed, low drag.

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