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EFE trouble understanding

  1. Mar 21, 2013 #1
    Hi I have been trying to teach my self the basics of Einsteins Field Equations, because I find them extremely interesting and there is a huge lack of EFE in the canadian high school curriculum. I have been trying to under stand the equation G=8pi*(G/c^2)T. I get what the equation is for ( the curvature of space) but I don't understand how to calculate the Momentum- Energy tensor (T). so that is my question, How do you calcuate for T? and also once you find the final value for "G" what unit is it in or is it a formula for a curve
  2. jcsd
  3. Mar 21, 2013 #2


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    Gold Member

    G and T in the equation are tensors, so it is usually written

    Rμσ - (1/2)Rgμσ = Gμσ = 8pi*(G/c^2)Tμσ

    Confusingly, the G on the right is Newton's constant. The greek indexes are spacetime indexes, so there are actually ( up to ) 10 equations, because G and T can have 10 independent components.

    You'll need to have some understanding of tensors to appreciate GR and that is a subject best learned from books or a course.

    This link may be be of some help

    Last edited: Mar 21, 2013
  4. Mar 21, 2013 #3
    thanks but i meant to ask is there like a unit of spacetime curve or is there another way to determine the magnitude of the curve with the value of Gμμ
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