Theories of gravity that obey the Weak Equivalence Principle have same Parametrised Post-Newtonian parameter $\gamma$ for all particles at energies. The large Shapiro time delays extragalactic sources allow us to put tight constraints on differences in between photons different frequencies from spectral lag data, since a non-zero $\Delta \gamma$ would result frequency-dependent arrival time. ma...

The Equivalence Principle (EP) is at the heart of General Relativity (GR), tested in many aspects. It often used to discuss qualitatively influence gravity on physical phenomena. But can this be made more precise? We compare clock rates, frequency shifts, light deflection and time delay simple static spacetimes analogous phenomena seen by accelerated observers Minkowski space. In contrast previ...

We highlight and resolve what we take to be three common misconceptions in general relativity, relating to (a) the interpretation of the weak equivalence principle and the relationship between gravity and inertia; (b) the connection between gravitational redshift results and spacetime curvature; and (c) the strong equivalence principle and the local recovery of special relativity in curved, dyn...