Einstein's theory of gravity, general relativity, has passed all tests with predictions that are spot-on. One prediction that remains is "gravitational wave memory"—the prediction that a passing ...

Whenever light interacts with matter, light appears to slow down. This is not a new observation and standard wave mechanics can describe most of these daily phenomena. For example, when light is ...

Lines of momentarily flat water extend outward and rotate, in the opposite direction to the flow of the vortex. The left video shows the pattern from the experiment, while the right video shows the ...

Can darkness really travel faster than light? A surprising new physics experiment suggests it can—at least in a very unusual way. Scientists observed dark regions within light waves moving faster than ...