Abstract

Einstein changed the problem of ether from the discussion of whether it exists to that of whether it is necessary as a concept or a hypothesis. It is true that if we give the vacuum the property as a medium that propagates light, it becomes unnecessary to search for ether as substance. Even so, we have to search for an experiment to decide whether the propagation of light emitted from light source is isotropic or anisotropic relative to the light source. An experiment like that was formerly considered nonexistent, but this paper will show it is existent. In the process of Thought experiment of this paper, we will find different results from the prediction by Special Relativity. As the cause of that, we will show the existence of an unknown velocity vector Einstein denied.