Reply #10: Nope, not even that [View All]

[TechBear_Seattle]

Light bends along the "curvature" of spacetime. Mass causes spacetime to curve (this curvature is manifest as gravity.) A light beam near the Earth can not follow a straight line, as it must follow the way spacetime curves due to the Earth's mass.

You would have to get extremely far out from any mass in order to come close to a straight line, and even then, the mass of the experimenter's body and the mass of the equipment conducting and detecting the experiment, would cause curvature of spacetime and thus cause light to not travel in a straight line.

So if you ask a theoretical physicist or mathematician, the answer is a flat out and absolute, "No." If you ask an engineer, however, the answer will be more like, "How straight is 'straight' and what is the distance it must stay within that limit?" :hi: