Presentation #304.08 in the session Space-based Instruments — iPoster Session.
Experimental confirmation of the isotropy of the one-way speed (OWS) of light remains an enigma in experimental physics, notwithstanding many numerous attempts to address it. The principal obstacle to the measurement of the OWS of light is the lack of synchronization between time clocks at points separated in space. In the formulation of Einstein’s Special Theory of Relativity, the constancy of the speed of light was conceptually assumed, but never experimentally confirmed. Clock synchronization at two distant points to measure the OWS of light with time-of-flight measurement techniques requires knowledge of the OWS of light, however, the OWS of light measurement requires synchronization of the clocks at the two distinct points. This circular argument has prevented the measurement of the OWS of light. Methods purported to measure the OWS of light with optical interferometers have been based on roundtrip optical delays and thus provided the average of the OWS in opposite directions. This precluded the measurement of the OWS of light. The method presented here is based on the joint use of zero-rest-mass unknown object velocities and the known velocity of an object with non-zero rest mass. A theoretical development based on a gravity-free Euclidian space is given for conceptual purposes. The major finding is that this methodology provides the theoretical and experimental frameworks for the measurement of the one-way speed of light that may be used to confirm Einstein’s constancy of light convention as well as provide a method of time synchronization of spatially distinct clocks. The measurement concept and the theoretical foundation are presented for an optical reflectometric approach and the method is extended to a time difference of arrival technique. These techniques, with experimental development, will provide a system suitable for interplanetary clock synchronization in the unlikely event that the constancy of light be refuted via the same methodology.