[sac-forum] Re: What is a Planet - Pluto no longer a Planet

On Wed, 16 Aug 2006 11:23:04 -0700, Paul Dickson wrote:

> >From http://en.wikipedia.org/wiki/Definition_of_planet:
> 
> The IAU published its definition proposal on August 16, 2006. This
> definition loosely follows the second option considered by the 19-member
> panel in 2005. In its exact wording, it is:
> 
>     âA planet is a celestial body that (a) has sufficient mass for its
>      self-gravity to overcome rigid body forces so that it assumes a
>      hydrostatic equilibrium (nearly round) shape, and (b) is in orbit
>      around a star, and is neither a star nor a satellite of a planet.â

Also from http://en.wikipedia.org/wiki/Definition_of_planet:

On August 18, an IAU poll showed most in favor of a proposal by Uruguayan
astronomer Julio Ãngel FernÃndez. On August 22, the proposal was
rewritten with two changes from the previous draft. The third and final
draft as submitted on August 24 was:

    A planet is a celestial body that (a) is in orbit around the Sun, (b)
    has sufficient mass for its self-gravity to overcome rigid body
    forces so that it assumes a hydrostatic equilibrium (nearly round)
    shape, and (c) has cleared the neighbourhood around its orbit.

    A dwarf planet is a celestial body that (a) is in orbit around the
    Sun, (b) has sufficient mass for its self-gravity to overcome rigid
    body forces so that it assumes a hydrostatic equilibrium (nearly
    round) shape, (c) has not cleared the neighbourhood around its orbit,
    and (d) is not a satellite. All other objects orbiting the Sun shall
    be referred to collectively as "Small Solar System Bodies".

        -Paul

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