If major laws of physics changed with distance or time, would there be measurements and/or experiments which would tell us? For example, suppose gravity got weaker or stronger over the age of the universe. A change in the gravitational constant would affect the life cycle of stars, which I suppose would be noticeable. For example Both the color and the time period of variation for variable stars depends on their mass. Those variable stars which are much farther away are being viewed as they were a long time ago. I would expect a variation in the constant of gravitation over time to result in some noticeable differences among variable stars at various distances (ergo various times). I have noticed articles speculating on the laws of physics and/or various constants changing with time or distance, but have never seen any description of the possible effects.