The speed of light is considered a fundamental constant. However, if the universe expands and everything within it scales up - space, time, measuring instruments - could it be that the speed of light is only seemingly constant because our reference frames also expand?
Key considerations:
- If cosmic expansion affects everything, then the relationship between light travel distance and time should also shift.
- If time itself changes alongside space, then light would remain constant relative to a shifting time scale.
- If this hypothesis holds, longterm interferometer experiments (such as LIGO) could reveal subtle changes in interference patterns over time-provided initial parameters remain fixed and no recalibration occurs.
Are there existing experiments or theoretical models that explore this possibility? If not, how could we design a test to measure whether light’s constancy is absolute or merely an illusion of expansion?
