A Direct Terrestrial Test of the Second Postulate of Special Relativity

Abstract

THE following is a preliminary report of an investigation performed to test directly, in a terrestrial experiment, the second postulate of special relativity, which states that the velocity of light is independent of the motion of the light source. A direct test means here that the velocity of the light from a moving source is measured by a time-of-flight technique and not by use of interference effects in a closed light path or a frequency measurement. Investigations of the last-mentioned type may lead to difficulties in the interpretation of the result and are therefore not very satisfactory, as pointed out by, for example, H. Dingle¹.