GPS doesn't prove space and time are related

submitted by jerryk from self.Physics

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[–]zyxzevn 1 insightful - 1 fun1 insightful - 0 fun2 insightful - 1 fun -  (3 children)

The GPS position is determined by the time it takes for satellite signals to arrive.
There is a small difference in clock-speed at different heights on earth.
In General Relativity this difference is predicted.

This can only be measured with very accurate atomic clocks. Too expensive for small GPS devices. The engineering solution (as in your quote) is to use the satellites to "calibrate" the clock of a GPS on earth.

The reason for "change in clock speed" are the more basic laws:
1- energy must be conserved,
2- matter can be turned into light.
When matter in gravity becomes light (positron+electron), all gravity potential energy is lost.
So to conserve energy light must somehow be different in gravity.

The main criticism of General Relativity is that Tensor mathematics is used completely wrong.
(a.o. by the inventor of Tensors himself).

What I see as a major problem with the theory of gravity = acceleration, is that electrical charged objects do not experience acceleration on their charges.
There is some complicated maths that is used as a mainstream explanation, but that maths looks false to me.

There are also some alternatives to General Relativity.
Ron Hatch and younger Einstein think that the the speed of light is different in different gravity strengths.

[–]ActuallyNot 1 insightful - 1 fun1 insightful - 0 fun2 insightful - 1 fun -  (2 children)

matter can be turned into light.

I don't think that's strictly correct. What's true is that energy including light, has mass.

When matter in gravity becomes light (positron+electron), all gravity potential energy is lost.

I don't think that's true either. If a positron and an electron annihilate each other the γ rays have the same mass, and the same gravitational potential energy as that positron and electron did.

The main criticism of General Relativity is that Tensor mathematics is used completely wrong.

I've never heard that criticism. How are tensors incorrectly used in GR?

[–]zyxzevn 1 insightful - 1 fun1 insightful - 0 fun2 insightful - 1 fun -  (1 child)

  1. matter+antimatter -> light + (optional other stuff)
  2. light has no mass, only energy.
  3. See

. Mechanics. - On the Analytical Expression that must be given to the Gravitational Tensor in Einstein's Theory.
A very nice paper by T. Levi-Civita in 1917, one of the inventors of Tensor Calculus, proving that Einstein's pseudotensor is nonsense because it leads to a first-order, intrinsic, differential invariant, which the pure mathematicians G. Ricci-Curbastro and T. Levi-Civita proved in 1900 does not exist!

. How far can one get with a Linear Field Theory of Gravitation in Flat Space-Time? An interesting treatment by Hermann Weyl (1944) proving that the standard linearization of Einstein's equations is inadmissible.

Sadly these problems did not lead to fundamental discussions.
Most discussions around GR end with logical fallacies to falsely support Einstein.

[–]ActuallyNot 1 insightful - 1 fun1 insightful - 0 fun2 insightful - 1 fun -  (0 children)

1 matter+antimatter -> light + (optional other stuff)

Yes. Specifically γ rays in the case you mention of electron + positron.

2 light has no mass, only energy.

No. All energy (famously) has a mass equal to m = E/c2 for the rest frame or more generally m = E/γc2 , where γ = 1/√(1 − v2 /c2 ). It causes a gravitational field due to that, and it is affected by gravitational fields.

Mechanics. - On the Analytical Expression that must be given to the Gravitational Tensor in Einstein's Theory.

I'll have read. But I note that in 1917, General Relativity wasn't in it's current form. There was all that "lamba" stuff to be worked through.

How far can one get with a Linear Field Theory of Gravitation in Flat Space-Time?

I'll have a read of that too. Perusing superficially this seems to be an exploration and extension of special relativity though.