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Can We Call Pluto and Charon a 'Binary Planet' Yet?

Posted by timothy on from the complex-gyrations dept.

astroengine writes The debate as to whether Pluto is a planet or a dwarf planet rumbles on, but in a new animation of the small world, one can't help but imagine another definition for Pluto. As NASA's New Horizons spacecraft continues its epic journey into the outer solar system, its Kuiper Belt target is becoming brighter and more defined. Seen through the mission's Long Range Reconnaissance Imager (LORRI) camera, this new set of observations clearly shows Pluto and its biggest moon Charon locked in a tight orbital dance separated by only 11,200 miles. (Compared with the Earth-moon orbital separation of around 240,000 miles, you can see how compact the Pluto-Charon system really is.) Both bodies are shown to be orbiting a common point — the "barycenter" is located well above Pluto's surface prompting a new debate on whether or not Pluto and Charon should be redefined as a "binary planet".

10 of 115 comments (clear)

  1. Admit it. by Anonymous Coward · · Score: 4, Funny

    You're just trying to troll Neil Tyson for the hilarity that ensues.

  2. Pluto's a dog. what's Goofy? by turkeydance · · Score: 5, Informative

    seriously....call Pluto what it is...ClickBait.

    1. Re:Pluto's a dog. what's Goofy? by TWX · · Score: 3, Insightful

      Heh. I'm happy for the IAU to take its sweet time on this. In the already small impact that space science has on daily life, the definition of a particular pair of bodies that themselves don't care a whit what people about 35AU is just about completely meaningless.

      --
      Do not look into laser with remaining eye.
  3. Outrageous discrimination! by mi · · Score: 5, Funny

    The debate as to whether Pluto is a planet or a dwarf planet rumbles

    What's with this "dwarf" nonsense — and big planetarism? We demand equal gravity for all planets!

    --
    In Soviet Washington the swamp drains you.
  4. Binary yes, planet no. by Henriok · · Score: 4, Insightful

    The arguments for demoting Pluto from its planetary status still holds. And hardly anyone objects to Pluto and Charon together as a binary system. But this "new" insight does not promote Pluto/Charon to planetary status. Binary dwarf planet, binary kuiper belt object, binary plutoid. Absolutely. Binary planet? No.

    --

    - Henrik

    - when the Shadows descend -
    1. Re:Binary yes, planet no. by jonfr · · Score: 3, Insightful

      Anything that is a sphere and orbits a star is a planet. Asteroids don't have sphere shape. Same goes for comets. The reason for the name "dwarf planets" is that of naming issue. There are more than 100 planet object out there, most of them smaller than planet Mercury.

      Haumea is a planet, but is minor elongated due it's rapid orbital period.

      http://en.wikipedia.org/wiki/H...

      List of other dwarf planets.

      http://solarsystem.nasa.gov/pl...

      Then there is a chance of Earth size planets (both above and below in size and mass) in the outer region of our solar system that have not yet been discovered. At least there are clues about them today, even if they have so far not yet been found. It is my guess they are going to be found, given time and advances in technology that allows for better detection of outer orbital planets in our solar system.

      http://www.space.com/7728-eart...
      http://www.theguardian.com/sci...

      There is a lot out there that we don't have no clue about and there are discoveries to be made (if the funding holds).

  5. What debate? by glwtta · · Score: 5, Informative

    Planet and Dwarf Planet are arbitrary labels defined by the IAU.

    How can you "debate" about that?

    --
    sic transit gloria mundi
  6. This is pretty damn silly by glwtta · · Score: 3, Interesting

    This mission will put a new spotlight on Pluto and its âoedwarf planetâ status, potentially highlighting its current classification as a woefully inadequate description of such a dynamic and interesting binary system.

    Ok, so it's a "binary dwarf planet" - can we tone down the prose now?

    --
    sic transit gloria mundi
  7. OOOps! by Unknown74 · · Score: 4, Informative

    My mistake...Pluto has FIVE moons. Charon: Discovered in 1978, this small moon is almost half the size of Pluto. It is so big Pluto and Charon are sometimes referred to as a double planet system. Nix and Hydra: These small moons were found in 2005 by a Hubble Space Telescope team studying the Pluto system. Kerberos: Discovered in 2011, this tiny moon is located between the orbits of Nix and Hydra. Styx: Discovered in 2012, this little moon was found by a team of scientists search for potential hazards to the New Horizons spacecraft flyby in 2015. may the 'little planet that could' keep right on thumbing it nose at everybody!

  8. Re:Self-awareness by Smauler · · Score: 4, Insightful

    Interestingly, Jupiter is the only planet which has it's barycenter with the sun outside of the sun.

    The definition of whether something orbits something else, or whether it is a binary system is pretty arbitrary. It would be nice and neat if we could say that if the barycenter is inside the larger body, the smaller body is orbiting the larger, but that would mean that Jupiter would not be orbiting the sun.