The speed of light was and still is a great puzzle that remains unsolved to date, despite all claims made by mainstream physics. The blunder in the conception of the Michelson-Morley experiment was that they considered light as ordinary, material waves. This led to Lorentz and Fitzgerald length-contraction hypothesis, which was another mistake. Einstein tried to correct all mistakes, by introducing one of the biggest mistakes in science: Special Relativity. A series of mistakes building on one another. The Michelson-Morley experiment was flawed in that it was conceived to detect something that never existed: the ether. The ether hypothesis should have been subjected to a thorough conceptual test even before doing a physical experiment. The Michelson-Morley experiment was/is incapable to detect absolute motion. The terms ‘absolute motion’ and ‘motion relative to ether’ were always wrongly presumed to be the same. The argument in this paper is that absolute motion exists, but the ether does not exist. Despite the failure of Michelson-Morley experiment, absolute motion was detected with several other kinds of experiments, such as the Sagnac, the Michelson-Gale, the Marinov, the Silvertooth, the Roland De Witte experiments. In this paper a new interpretation of absolute motion and the speed of light is proposed that can be stated in a few words: the speed of light is constant relative to the apparent source. The effect of absolute motion is to create an apparent change in the position (distance and direction) of a light source relative to the observer. For co-moving source and observer, the effect of absolute motion is to create a change in the path length, and not the speed, of light. Thus an apparent change in the position of the light source ( relative to the detector) in the Michelson-Morley experiment will not create any significant fringe shift for the same reason that a real/physical change of the source position will not create any significant fringe shift. This is the subtle trick of nature that has eluded physicists for one hundred years. Apparent Source Theory (AST) consistently explains the Michelson- Morley experiment, Sagnac effect and moving source experiments. Any true theory of the speed of light should convincingly explain both the Michelson-Morley and Sagnac experiments before making any other claims. AST hints on the fundamental nature of light itself. Light is a dual phenomenon : local and non-local.