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Gravitational force vs space time fabric

  1. Feb 27, 2009 #1
    Hi guys, I got a question that has been in my head for a while.
    Is the newtonian gravitional force equivalent to the "tension" in the space time fabric caused by the depression of 2 masses? If it is equivalent, does it means that gravitional force does not act in a straight line but it spread across the curvature in the space time fabric? If it is not, then what is the newtonian gravitional force representation in general relativity?
  2. jcsd
  3. Feb 27, 2009 #2
    Did you mean "stress" instead of "tension"...??

    (1) no
    (2) no
    (3) GR simplifies to Newtonian attraction at low energies and pressures. Newtonian gravity asserts the strength of gravitational attraction between two objects is due only to their masses and the distance between them. period.

    GR attributes gravity to curvature of spacetime, not to force, and asserts that not just mass contributes the the strength of the gravitational field but energy and pressure as well.

    The concept of pressure leads to positive pressure contributing to ordinary gravitational attraction, while negative pressure contributes to repulsive gravity....hence the cosmological constant.

    A finite mass, like a planet, ends up having curved space time fabric...but an infinite plane of mass, for example, would not have such curved space time fabric...no tidal forces...this is the kind Einstein envisioned in his "equivalence" principle....
  4. Feb 27, 2009 #3
    Thx alot Naty1 for yr help
    I have gotten a clearer picture now
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