A critical discussion about GravitationScrutiny of experimental observations of light bending, one of the determinant proofs of General Relativity, suggests a clue of profound significance; gravity appears to deflect EM radiation proportionally to its frequency. Differences in the deflection of light beams and microwave radiation are minimal, but statistically appreciable. The GEM Experiment proposed in the text aims to employ a tunable source of gamma rays, about the Higgs resonance, as