Scientists pushed photons across the universe to test the speed of light—and found Einstein’s cosmic speed limit still holds ...

Einstein’s claim that the speed of light is constant has survived more than a century of scrutiny—but scientists are still daring to test it. Some theories of quantum gravity suggest light might ...

The speed of light has been one of science’s most trusted markers of stability. For more than a century, the idea that light moves through space at a constant speed has supported some of physics’ most ...

Our modern understanding of the physical world is based on gauge theories: mathematical models from theoretical physics that describe the interactions between elementary particles (such as electrons ...

Classical physics theories suggest that when two or more electromagnetic waves interfere destructively (i.e., with their electric fields canceling each other out), they cannot interact with matter. In ...

Addressing a controversy first raised around 1910, two physicists have performed experiments with the aid of an engineer that validate anew the special theory of relativity’s limitations on the speed ...