Tests of equivalence principle and galactic center
I understand that many experiments have been carried out in order to check the Equivalence Principle.
Most experiments seem to check for differences between the inertial behavour of two test objects (like dropping a feather and a stone simultaneously on the moon!)
Have any experiments looked for absolute changes in the inertia of an object when it is accelerated in different directions?
Following Mach's principle my hunch is that the ratio of an object's inertial to gravitational mass might vary by 10^-5 according to whether its acceleration is in line with the galactic center or at right angles to it.