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.

The 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.

Repetitions
Additional experiments of this class are described (Archive). The first experiment in this list is the Princeton experiment 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.

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: