Given that there seems to exist only one objective reality, no experiment repeatably giving always the same outcome can be proven false if objectively existing gravity is proven to be an electromagnetic force, because by definition, they all then could only be manifestation of this force.

We already have evidence for this from the countless repeated occurrences of successful application of well understood electromagnetic processes that underlie the development of all engineering applications using the electromagnetic properties of matter, like countless successfully working electric motors in existence and all electronic devices that we benefit from also existing now in their countless successfully working millions of existing units.

If interested, an exploration of this possible foundation of physical reality is available from this series of papers published about electromagnetic mechanics since 2007:

Article INDEX -Electromagnetic Mechanics (The 3-Spaces Model)

If gravity were an electromagnetic force, then there would be no need for spatial distortion. However, GPS technology ensures high accuracy by taking into account the existence of spatial distortion. Therefore, a different hypothesis is needed to explain the mechanism by which gravity occurs.

General Relativity describes the time shift; my electromagnetic model explains its cause. ""

General Relativity predicts the time difference but does not explain its true cause at the atomic or quantum level. My research shows that if gravity is electromagnetic, the effect on atomic clocks is a direct result of changes in the local electromagnetic environment. This gives a clear, testable physical mechanism for why time runs differently near massive bodies — something current theory only describes mathematically.

Quote: "However, GPS technology ensures high accuracy by taking into account the existence of spatial distortion."

It is not so. Contrary to the urban legend that runs rampant even in some scientific circles, neither the General Relativity theory spacetime curvature nor the Special Relativity time dilation were involved in the establishment of the GPS system nor of any of the other global positionning systems. The calculation technique used is simple multilateration.

The so-called time dilation hypothesized with the SR theory to explain atomic clocks increase in rate with decreasing intensity of the gravitational gradient with altitude is easily explained in electromagnetic theory by the contraction of all electronic orbitals in all atoms of masses moving away from the large mass of the Earth, which causes the reference photons emitted as electrons deexcites from the metastable reference orbital of the clock's caesium atoms to their rest reference orbitals to be more energetic in altitude than if emitted from the same atom at the surface of the Earth;

Put in general perspective in this paper published in 2013:

Article Inside Planets and Stars Masses

Yes, I agree — GPS positioning is based on multilateration, and while relativistic corrections are applied, General Relativity does not explain the real physical cause of the time difference. The change in clock rates with altitude can be explained by known electromagnetic principles: as distance from Earth increases, the local gravitational–electromagnetic field changes, causing atomic orbitals to contract and the reference photons in atomic clocks to become slightly more energetic. This is exactly the type of mechanism my electromagnetic model of gravity describes — it matches GPS corrections in practice but gives a real atomic-level reason for why the effect happens, not just a mathematical description.

If gravity were proven to be an electromagnetic force, **Cavendish's torsion balance experiment (1798)** would be proven wrong because it measures gravitational attraction between neutral masses, which should not interact electromagnetically. For example, if two lead balls (electrically neutral) still attracted each other without an EM charge, it would contradict gravity being purely electromagnetic.

This would also conflict with Einstein's Equivalence Principle, as electromagnetic forces depend on charge, while gravity affects all masses equally.

Quote: "If gravity were proven to be an electromagnetic force, **Cavendish's torsion balance experiment (1798)** would be proven wrong because it measures gravitational attraction between neutral masses, which should not interact electromagnetically."

It is not so, for the simple reason that all macroscopic masses, including of course those used with the Cavendish torsion balolance, all are accumulations of atoms, which are all almost empty stable local systems of charged and massive elementary electromagnetic particles, that are the only carriers of mass in the universe.

Even in Cavendish's time, before it was known that all macroscopic masses were made only of charged elementary electromagnetic particles, these elementary particles were already as they always were since the beginning of the universe. And the now known fact that they are electromagnetic in nature cannot possibly change the outcome of the Cavendish torsion ballance experiment.

If carried out today, knowing now that matter is made of these atoms, themselves made of electromagnetic elementary particles, the Cavendish experiment would result in the exact same outcome.

Matter today is the same as in Cavendish's time. Einstein's opinion does not change the nature of macroscopic masses.

André Michaud Salwa IbrahimCavendish’s torsion balance experiment does not prove that gravity is a separate force. What he really measured was the attraction between “neutral” lead spheres. In my research, I explain this through the Nuclear Polarization Force. A neutral body is not truly charge-free. The nucleus carries a positive charge, while the surrounding electrons only partially shield it. Because of this incomplete shielding, atoms still exert a very weak residual force on each other. This weak attraction increases with the number of atoms, so it looks like Newtonian gravity. Think of it this way: a neutral body can be attracted by a positive charge, even though it has no overall negative charge. How is this possible? It is possible due to polarization — the electrons inside the neutral body shift slightly, creating an induced attraction. On the atomic scale, the same principle works between nuclei and neutral atoms, giving rise to what I call the Nuclear Polarization Force. Therefore, Cavendish was correct in detecting an attraction, but what he saw was not a mysterious “gravitational force.” It was actually the cumulative effect of this weak residual electromagnetic interaction at the nuclear level.

Note that it is easily demonstrated mathematically that all classical force equation are derivations from the fundamental acceleration equation F=ma. Formally published in 2013:

Article Unifying All Classical Force Equations