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Metric Tensor for a Sphere

  1. Jun 24, 2011 #1
    Does anyone know what the metric tensor looks like for a 2 dimensional sphere (surface of the sphere)?

    I know that it's coordinate dependent, so suppose you have two coordinates: with one being like "latitude", 0 at the bottom pole, and 2R at the northern pole, and the other being like longitude, 0 on 1 meridian and Pi * R on the opposite side (here, 2 Pi R gives you the same location as 0).

    I've searched online and can't find a simple example of this basic metric tensor... :-(

    The other one I'm curious about is the surface of a hyperbola (again, think 2-D surface of a shape in 3 dimensions). What is the metric on THAT surface?

    Any type of help is greatly appreciated...
  2. jcsd
  3. Jun 24, 2011 #2

    George Jones

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    The standard metric is
    [tex]ds^2 = R^2 \left( d\theta^2 + sin^2\theta d\phi^2 \right).[/tex]
  4. Jun 25, 2011 #3


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    Note: George Jones is using the physics notation which takes [itex]\phi[/itex] as the "longitude" and [itex]\theta[/itex] as "co-latitude", the opposite of mathematics notation.
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