[meteorite-list] Defining 'Planet': Newfound World Forces Action

[Francis Graham]

> >
> > A planet is a body that directly orbits a star, is
> large enough to be
> > round because of self gravity, and is not so large
> that it triggers
> > nuclear fusion in its interior.
> >

   This is a very sensible definition. We should have
no aversion to calling Pluto, Xena, Sedna and Quauoar
planets. 
   One minor quibble.  The Earth was large enough to
evolve human beings (I don't think we'd see humans
evolve on Ceres!) , who set off underground hydrogen
bomb tests. Therefore, the Earth is not a planet
strictly by this definition. 

Francis Graham



		
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