Science > Physics > Gravitational Potential of Arda, a Tolkienesque Physics Problem
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Science > Physics |
| User: |
"Robert J. Kolker" |
| Date: |
09 Feb 2004 04:44:28 PM |
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Gravitational Potential of Arda, a Tolkienesque Physics Problem |
In Tolkien's mythological world, the Earth, or Arda is a flat, non
spinning disk (circular symmetry). What is the gravitational potential
of such an earth given that its density is uniform throughout and its
diameter is much greater than its thickness. I assume gravity would be
weakest in the middle and on the edges.
Bob Kolker
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| User: "Greg Neill" |
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| Title: Re: Gravitational Potential of Arda, a Tolkienesque Physics Problem |
09 Feb 2004 05:34:05 PM |
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"Robert J. Kolker" <bobkolker@NOSPAMcomcast.net> wrote in message
news:g3UVb.263620$xy6.1334310@attbi_s02...
In Tolkien's mythological world, the Earth, or Arda is a flat, non
spinning disk (circular symmetry). What is the gravitational potential
of such an earth given that its density is uniform throughout and its
diameter is much greater than its thickness. I assume gravity would be
weakest in the middle and on the edges.
It would be a strange world. The gravitational field
would only be perpendicular to the surface of the
disk's flat side at the central axis. Everywhere
else on the flat side it would point partially
"downwards" to the surface, and partially towards
the central axis. At the rim of the flat side,
gravity would point almost totally towards the
central axis (assuming a disk that's thin with
respect to its radius).
To denizens of the disk world, travelling to the rim
would be like scaling a nearly shear cliff.
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| User: "Franz Heymann" |
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| Title: Re: Gravitational Potential of Arda, a Tolkienesque Physics Problem |
10 Feb 2004 05:19:13 AM |
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"Robert J. Kolker" <bobkolker@NOSPAMcomcast.net> wrote in message
news:g3UVb.263620$xy6.1334310@attbi_s02...
In Tolkien's mythological world, the Earth, or Arda is a flat, non
spinning disk (circular symmetry). What is the gravitational potential
of such an earth given that its density is uniform throughout and its
diameter is much greater than its thickness. I assume gravity would be
weakest in the middle and on the edges.
Why not dothe integral and look up the ellipticontegrals as they occur?
Franz
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| User: "Bjoern Feuerbacher" |
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| Title: Re: Gravitational Potential of Arda, a Tolkienesque Physics Problem |
10 Feb 2004 07:25:45 AM |
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"Robert J. Kolker" wrote:
In Tolkien's mythological world, the Earth, or Arda is a flat, non
spinning disk (circular symmetry).
Well, only in the first two ages - it was changed to a sphere when
Numenor was destroyed, IIRC.
What is the gravitational potential
of such an earth given that its density is uniform throughout and its
diameter is much greater than its thickness. I assume gravity would be
weakest in the middle and on the edges.
I think that applying our laws of physics to Tolkien's world is a bit,
well, misguided. I would think that when the shape of Arda was changed,
the laws of physics were also changed to the ones we observe today.
For *real* answers: see the post by Greg Neill.
Bye,
Bjoern
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| User: "Ian Stirling" |
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| Title: Re: Gravitational Potential of Arda, a Tolkienesque Physics Problem |
09 Feb 2004 05:45:21 PM |
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Robert J. Kolker <bobkolker@nospamcomcast.net> wrote:
In Tolkien's mythological world, the Earth, or Arda is a flat, non
spinning disk (circular symmetry). What is the gravitational potential
of such an earth given that its density is uniform throughout and its
diameter is much greater than its thickness. I assume gravity would be
weakest in the middle and on the edges.
I don't recall it being specifically stated.
Might not the charachters (who?) be confused?
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