Michelson and Morley conducted experiments to investigate the possibility of luminiferous aether being present in the universe for light beam propagation. Is the experiment appropriate for detecting aether in the universe or not? Morley and Michelson conduct such exquisite experiments. However, there seems to be a discrepancy between the experimental and theoretical data. This may be because the derivation of the Michelson and Morley experiment did not include the speed of the light source. The objective of this theory is to use the new derivation of the Michelson and Morley experiment to include the light source speed and to observe the result. The main aim of this theory is to demonstrate that the velocity of light is relative, rather than independent. Interestingly, there has been little discussion about the source speed of light until now. In this paper, we utilize the classical mechanics of relative motion to derive the Michelson and Morley experiment. By introducing the light source speed in the derivation, our theoretical and experimental values will match. However, further experiments are required to fully prove whether the speed of light is constant or relative and whether it is dependent or independent.