Limited Validity of the Second Postulate of the STR

The velocity of light is one of the most fundamental questions in physics. For centuries, the velocity of light has been a subject of scientific discussion. In this article, we will discuss this subject based on the experimental data. Marmet measured in 2000 that light needs 14 μs more when traveling in the direction S.F to N.Y., when traveling back in the opposite direction. These data are the main tools of this research. The result of the research is that light has a constant velocity in a still medium. In the dynamic medium velocity of light increases or decreases depending on the position of the apparatus that measures its velocity. The second postulate of STR is valid only in a stationary ether.