FYI, this, uploaded about a week ago:

https://www.researchgate.net/publication/372245510_Principles_of_Gravitomagnetism_I_-_Unavoidability

The paper gives between twenty or thirty arguments for the inescapable existence of velocity-dependent gravitomagnetic (v-gm) effects.

It also points out that special relativity's equations, designed for flat spacetime, can't be used as a foundation for a valid general theory of relativity.

IN THE SR WORLDVIEW:
* Special relativity has a very specific set of Doppler equations (1905 paper) derived from the assumption of flat, undisturbed spacetime.
* If we assume that these relationships are correct, and apply them, they //enforce// flat spacetime in the sense that they make it impossible for there to be intrinsic curvature of the metric as a function of the speed that bodies move through it: no such thing as a velocity-based GM effect.
* Without v-gm, a rotating star can't drag light around with it.
* ... and without v-GM, we can't have a higher-order version of GM for acceleration.

So the SR relationships, on their own, even without any of the interpretational infrastructure normally associated with SR, are sufficient to "prove" that there can be no such thing as gravitomagnetism.

//Snag is//, the general principle of relativity insists that GM effects must be real. Accelerative and rotational GM effects, for all accelerating and rotating masses, have to exist for the principles of relativity of acceleration and rotation to work. Without GM, we cannot have a general principle of relativity, or a general theory of relativity, and with SR, we can't have GM.

The SR equations make a general theory impossible.

So it's a little unfortunate that Einstein tried to build his 1916 general theory on an SR //foundation//, and wrote SR-compliance into the definitions of his theory.

Consequently:
1: If we want to believe that special relativity is truly correct physics, then we must give up forever the idea of having a general theory. SR just isn't extensible to cover moving gravitational objects, at the level of its basic equations. Ad you can't adapt or modify the SR equations without breaking the theory.
2: On the other hand, if we WANT a general theory of relativity (that works), then the price we have to pay is that we must give up special relativity.

SR is inertial physics in flat spacetime.
Under general theory, we cannot have inertia without gravitation/curvature, and the concept of "inertial physics in flat spacetime" becomes paradoxical. Under a GTR, "physics" and "flat spacetime" are mutually exclusive concepts: if a region is flat, then there is no mass present and no mass-physics going on ... if mass-physics IS going on, the region is, pretty much by definition, then not flat.

3. Einstein's 1916 attempt at a general theory, defined as supporting both the general principle AND the SR relationships, is a geometrical impossibility. It just can't be done. The 1916 theory is pathological.

Anyway, enjoy the paper
Eric Baird
https://www.researchgate.net/publication/372245510_Principles_of_Gravitomagnetism_I_-_Unavoidability

On Wednesday, July 19, 2023 at 3:49:58 PM UTC-7, Eric Baird wrote:
> FYI, this, uploaded about a week ago:
>
> https://www.researchgate.net/publication/372245510_Principles_of_Gravitomagnetism_I_-_Unavoidability
>
> The paper gives between twenty or thirty arguments for the inescapable existence of velocity-dependent gravitomagnetic (v-gm) effects.
>
> It also points out that special relativity's equations, designed for flat spacetime, can't be used as a foundation for a valid general theory of relativity.
>
> IN THE SR WORLDVIEW:
> * Special relativity has a very specific set of Doppler equations (1905 paper) derived from the assumption of flat, undisturbed spacetime.
> * If we assume that these relationships are correct, and apply them, they //enforce// flat spacetime in the sense that they make it impossible for there to be intrinsic curvature of the metric as a function of the speed that bodies move through it: no such thing as a velocity-based GM effect.
> * Without v-gm, a rotating star can't drag light around with it.
> * ... and without v-GM, we can't have a higher-order version of GM for acceleration.
>
> So the SR relationships, on their own, even without any of the interpretational infrastructure normally associated with SR, are sufficient to "prove" that there can be no such thing as gravitomagnetism.
>
> //Snag is//, the general principle of relativity insists that GM effects must be real. Accelerative and rotational GM effects, for all accelerating and rotating masses, have to exist for the principles of relativity of acceleration and rotation to work. Without GM, we cannot have a general principle of relativity, or a general theory of relativity, and with SR, we can't have GM.
>
> The SR equations make a general theory impossible.
>
> So it's a little unfortunate that Einstein tried to build his 1916 general theory on an SR //foundation//, and wrote SR-compliance into the definitions of his theory.
>
> Consequently:
> 1: If we want to believe that special relativity is truly correct physics, then we must give up forever the idea of having a general theory. SR just isn't extensible to cover moving gravitational objects, at the level of its basic equations. Ad you can't adapt or modify the SR equations without breaking the theory.
> 2: On the other hand, if we WANT a general theory of relativity (that works), then the price we have to pay is that we must give up special relativity.
>
> SR is inertial physics in flat spacetime.
> Under general theory, we cannot have inertia without gravitation/curvature, and the concept of "inertial physics in flat spacetime" becomes paradoxical. Under a GTR, "physics" and "flat spacetime" are mutually exclusive concepts: if a region is flat, then there is no mass present and no mass-physics going on ... if mass-physics IS going on, the region is, pretty much by definition, then not flat.
>
> 3. Einstein's 1916 attempt at a general theory, defined as supporting both the general principle AND the SR relationships, is a geometrical impossibility. It just can't be done. The 1916 theory is pathological.
>
> Anyway, enjoy the paper
> Eric Baird
> https://www.researchgate.net/publication/372245510_Principles_of_Gravitomagnetism_I_-_Unavoidability

The Earth is a rotating macro magnet that has its own gravity.
The Earth gravito-magnetism is in orbit.

On Wednesday, July 19, 2023 at 3:49:58 PM UTC-7, Eric Baird wrote:
> FYI, this, uploaded about a week ago:
>
> https://www.researchgate.net/publication/372245510_Principles_of_Gravitomagnetism_I_-_Unavoidability
>
> The paper gives between twenty or thirty arguments for the inescapable existence of velocity-dependent gravitomagnetic (v-gm) effects.
>
> It also points out that special relativity's equations, designed for flat spacetime, can't be used as a foundation for a valid general theory of relativity.
>
> IN THE SR WORLDVIEW:
> * Special relativity has a very specific set of Doppler equations (1905 paper) derived from the assumption of flat, undisturbed spacetime.
> * If we assume that these relationships are correct, and apply them, they //enforce// flat spacetime in the sense that they make it impossible for there to be intrinsic curvature of the metric as a function of the speed that bodies move through it: no such thing as a velocity-based GM effect.
> * Without v-gm, a rotating star can't drag light around with it.
> * ... and without v-GM, we can't have a higher-order version of GM for acceleration.
>
> So the SR relationships, on their own, even without any of the interpretational infrastructure normally associated with SR, are sufficient to "prove" that there can be no such thing as gravitomagnetism.
>
> //Snag is//, the general principle of relativity insists that GM effects must be real. Accelerative and rotational GM effects, for all accelerating and rotating masses, have to exist for the principles of relativity of acceleration and rotation to work. Without GM, we cannot have a general principle of relativity, or a general theory of relativity, and with SR, we can't have GM.
>
> The SR equations make a general theory impossible.
>
> So it's a little unfortunate that Einstein tried to build his 1916 general theory on an SR //foundation//, and wrote SR-compliance into the definitions of his theory.
>
> Consequently:
> 1: If we want to believe that special relativity is truly correct physics, then we must give up forever the idea of having a general theory. SR just isn't extensible to cover moving gravitational objects, at the level of its basic equations. Ad you can't adapt or modify the SR equations without breaking the theory.
> 2: On the other hand, if we WANT a general theory of relativity (that works), then the price we have to pay is that we must give up special relativity.
>
> SR is inertial physics in flat spacetime.
> Under general theory, we cannot have inertia without gravitation/curvature, and the concept of "inertial physics in flat spacetime" becomes paradoxical. Under a GTR, "physics" and "flat spacetime" are mutually exclusive concepts: if a region is flat, then there is no mass present and no mass-physics going on ... if mass-physics IS going on, the region is, pretty much by definition, then not flat.
>
> 3. Einstein's 1916 attempt at a general theory, defined as supporting both the general principle AND the SR relationships, is a geometrical impossibility. It just can't be done. The 1916 theory is pathological.
>
> Anyway, enjoy the paper
> Eric Baird
> https://www.researchgate.net/publication/372245510_Principles_of_Gravitomagnetism_I_-_Unavoidability

GR and SR are common in their basis. They are both based on speed.
Space travel shows time slow by accelerating motion.
Strength of gravity decelerates time.