Torsion Balance Experiments

The Equivalence Principle tests are incredibly reliable precision machines which are used to measure the Equivalence Principal to increasing sensitivity. Experimenters have redesigned the Equivalence Principle's Torsion Balance tests to try and detect the gravity variations caused by the sun, moon, and the tidal forces. It was found that the gravitational influence of the sun, moon, or the tidal forces could not be measured as manifest of the attraction of the bodies in the experiments. Variations to "gravity" did not appear.

Princeton Experiment
From 'The Pendulum Paradigm: Variations on a Theme and the Measure of Heaven and Earth', by Professor Martin Beech, we read the following on p.176:



Essentially, the experiment is summarized as follows:

The masses were not attracted to the sun in the experiment, to an accuracy of one part in one hundred billion.

Moscow State University Experiment
The experiment was repeated and improved by researchers at Moscow State University:

Verification of the Equivalence of Inertial and Gravitational Mass V. B. Branginsky and V. I. Panov Full Text Link (Archive)

Repetitions
Additional experiments of this class are described (Archive). The two experiments experiment in this list is the Princeton and Moscow State experiments above:

The Eöt-Wash experiments were repeated by others:

https://plato.stanford.edu/entries/physics-experiment/app4.html (Archive)

Equivalence Principle Violation
An Eöt-Wash presentation explains (Archive) that the influence of an external source mass on these type of experiments would be a violation of the Equivalence Principle (EP).



The Equivalence Principle has never been violated. See Evidence for the Universal Accelerator.

Eöt-Wash Hill Experiments
From No Easy Answers: Science and the Pursuit of Knowledge by Allan Franklin, on p.70 we read a summary of the Eöt-Wash hillside experiments with the rotating torsion balance:

Study Link

History of the Torsion Balance
The history of the Torsion Balance experiments began in 1889, with Barron Rosland von Eötvös' attempt to detect the Coriolis force.

Foundations of Modern Cosmology By Professor John F. Hawley, and Katherine A. Holcomb

From p.219 of the above text we read:

Further reading on Eötvös' inability to detect the Coriolis force is found starting on p.52 of Gravity's Mysteries: From Ether to Dark Matter By Louis Komzsik.

Addendum
The reader should note that the principle of equivalence of inertial and gravitational mass even stretches to the point where the earth only appears to be accelerating upwards, and the gravity of other celestial bodies does not appear to exist at all; exactly as is described in the popular analogies of a rocket traveling upwards at 1g in space far away from gravitating bodies.