5 ms·

GR agrees (recognizing the obvious caveats) with the classical law of F = Gm₁m₂/r², where F stands for "force". This force is caused by spacetime curvature.

pdonis 2y ago
No, GR says that the Newtonian law of gravity is an approximation that makes reasonably accurate predictions when the spacetime curvature is small and all relative motions are slow compared to the speed of light. It does not say that the Newtonian interpretation of that equation is correct.
- MockObject 2y ago
  > GR says that the Newtonian law of gravity is an approximation that makes reasonably accurate predictions when the spacetime curvature is small and all relative motions are slow compared to the speed of light. These are merely the aforementioned caveats. > It does not say that the Newtonian interpretation of that equation is correct. If the interpretation were wrong, and that's not a force, then the amount of force in that equation would be 0. With no force, Gm₁m₂/r² = 0. However, that's not the modification that GR applies to this, though.
  - pdonis 2y ago
    > If the interpretation were wrong, and that's not a force, then the amount of force in that equation would be 0. With no force, Gm₁m₂/r² = 0. Nonsense. The GR interpretation is that G m1 m2 / r^2, when it is nonzero, is describing an effect of spacetime geometry, not a force. It can't be a force in GR because it isn't felt; an object moving solely under the influence of G m1 m2 / r^2 feels no weight--an accelerometer attached to it reads zero. GR does not change the numerical value of G m1 m2 / r^2 at all. It just reinterprets what the quantity represents.
    - lazide 2y ago
      This is the bookkeeping/accounting part of it, BTW. It clearly exists (as a thing). What we decide to call it, and how we account for it, while important, doesn't make it not exist in reality. Despite the motte and bailey argument to the contrary.

pdonis 2y ago

No, GR says that the Newtonian law of gravity is an approximation that makes reasonably accurate predictions when the spacetime curvature is small and all relative motions are slow compared to the speed of light. It does not say that the Newtonian interpretation of that equation is correct.

MockObject 2y ago
> GR says that the Newtonian law of gravity is an approximation that makes reasonably accurate predictions when the spacetime curvature is small and all relative motions are slow compared to the speed of light. These are merely the aforementioned caveats. > It does not say that the Newtonian interpretation of that equation is correct. If the interpretation were wrong, and that's not a force, then the amount of force in that equation would be 0. With no force, Gm₁m₂/r² = 0. However, that's not the modification that GR applies to this, though.
- pdonis 2y ago
  > If the interpretation were wrong, and that's not a force, then the amount of force in that equation would be 0. With no force, Gm₁m₂/r² = 0. Nonsense. The GR interpretation is that G m1 m2 / r^2, when it is nonzero, is describing an effect of spacetime geometry, not a force. It can't be a force in GR because it isn't felt; an object moving solely under the influence of G m1 m2 / r^2 feels no weight--an accelerometer attached to it reads zero. GR does not change the numerical value of G m1 m2 / r^2 at all. It just reinterprets what the quantity represents.
  - lazide 2y ago
    This is the bookkeeping/accounting part of it, BTW. It clearly exists (as a thing). What we decide to call it, and how we account for it, while important, doesn't make it not exist in reality. Despite the motte and bailey argument to the contrary.