- The speed of light is independent of the motion of the source relative to the observer. d.
- The speed of light is different in different frames of reference.
- The speed of light changes with changes in the observer.
- The speed of light is dependent on the motion of the source.
This is College Physics Answers with Shaun Dychko. The Michelson-Morley experiment show that when the Earth is going around the Sun and you make a measurement of the speed of light as, you know, here's the velocity of the Earth going in its orbit around the Sun. When you measure the speed of light on Earth and you measure it going either, you know, along the direction of orbital velocity. So we measure the speed of light as the lighted beam is traveling this way. And compare that with measuring the speed of light when the beam is traveling perpendicular to the orbital velocity, you get the same result and this was surprising because it refuted the idea of an ether through which light travels. And so essentially what this means is that the speed of light does not depend on how the source is moving with respect to the observer. And so the answer is (a).