Re: Planet Definition

agnifire@xxxxxxxxx wrote:

:A planet is a celestial body that (a) is by far the largest object in
:its local population[1], (b) has sufficient mass for its self-gravity
:to overcome rigid body forces so that it assumes a hydrostatic
:equilibrium (nearly round) shape (c) does not produce more energy that
:it absorbs from the sun over the life of the object.(d) The object must
:lie close to the plane of the elliptic.

Why d)?

:Some people want to have a requirement that the body does not produce
:energy by any nuclear fusion mechanism. The problem with that is 2
:billion years ago in Oklo, Gabon, Africa natural nuclear reactor was
:formed when a uranium-rich mineral deposit became inundated with
:groundwater that acted as a neutron moderator, and a strong chain
:reaction took place.

That's fission, not fusion.

:I think we need a condition that prevents wandering celestial objects
:from being considered planets.which is the object must lie close the
:plane of the elliptic.

That doesn't do it. What if a wanderer just happens to come in on the
plane of the ecliptic (not elliptic)?

:That lets Pluto out. I like Pluto because when I
:was young it was the most distant planet from the sun and now Neptune
:is.

So if evidence came forward that, say, Earth was a 'wanderer' it would
suddenly not count as a planet for you?

--
"Some people get lost in thought because it's such unfamiliar
territory."
--G. Behn
.

Relevant Pages

  • Re: Planet Definition
    ... :>:A planet is a celestial body that is by far the largest object in ... :>:lie close to the plane of the elliptic. ... :All the others do and it indicates that the formation of the planet was ... What if a wanderer just happens to come in on the ...
    (sci.space.policy)
  • Re: Planet Definition
    ... :A planet is a celestial body that is by far the largest object in ... :lie close to the plane of the elliptic. ... All the others do and it indicates that the formation of the planet was ... So if evidence came forward that, say, Earth was a 'wanderer' it would ...
    (sci.space.policy)
  • Re: "Pluto Now Called a Plutoid"
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  • Planet Definition
    ... A planet is a celestial body that is by far the largest object in ... energy by any nuclear fusion mechanism. ... I like Pluto because when I ... was young it was the most distant planet from the sun and now Neptune ...
    (sci.space.policy)
  • Definition of a Planet
    ... A planet is a celestial body that is by far the largest object in ... energy by any nuclear fusion mechanism. ... I like Pluto because when I ... was young it was the most distant planet from the sun and now Neptune ...
    (sci.astro)