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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".

5 of 115 comments (clear)

  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.
  2. 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).

  3. Pluto is a Planet by sexconker · · Score: 1, Insightful

    Pluto is a planet. The definition of a planet is arbitrary, and always will be.
    Trying to forcefully change the definition after it's already in use is fucking retarded and does nothing but cause confusion.

    For other instances of dipshits trying to hijack language and make it worse, see "non-flammable" and the dipshits who insist that a kilobyte is 1000 bytes.

  4. 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.