OneWay Speed of Light Links One-way speed of light – Wikipedia one way speed of light crackpot – Google Search TIL that no one has ever measured the one-way speed of light. In fact it is undefined. All measurements of light speed are done using two-way (mirror) setups. It is entirely possible that light travels at c from A to B, and instantaneously from B to A, for a round trip speed of c. : r/todayilearned (1001) We only measured the two-way speed of light and then divided it by two, assuming it’s the same in all directions. What potential implications could arise for our understanding of causality if the speed of light is variable? – Quora Source: OneTab – Shared tabs