- #36
Ambitwistor
- 927
- 1
Originally posted by Albrecht
How do you fix the radius? How do you measure the circumference? You will have to use some kind of mechanical (or optical) equipment. This equipment undergoes changes in a gravitational field. So there cannot be an independent measurement of the space itself.
It doesn't matter whether the space is "really curved" or all your measuring instruments are changing in a way that makes it look curved: if the ratio comes out other than π&, then space is defined to be curved.
No, why should that be? I repeat the point: we do not need a specific theory of gravity.
Of course we do. We need to be able to predict the orbits of bodies, the deflection of light, etc. If you want to explain these gravitational effects by a variable light speed, fine, but you still need a theory.
The variance of the speed of light near a big object is an experimentally proven fact.
The speed of light varies in a non-inertial frame. If you want to postulate the speed of light as a scalar-valued field in space, you're welcome to, but this is not proven by Shapiro or anyone else -- it is not the same as general relativity's prediction, and you need to test it.
The cause of it is most probably the interaction of the particle (photon...) with the field of the other forces inside the object.
Speculation ignored. Try again if you ever develop a theory.
Both axioms you mention are "equivalent" to the equivalence principle.
Both axioms have the equivalence principle as consequences.
My question was: where is the experiment which is precise enough to decide about the factor of 1.5 ?
I already answered your question.