Darkness can move faster than light without breaking relativity
A dark point inside a wave of light sounds like a contradiction. It is also something researchers say they have now viewed in real time, moving so quickly that, by one measure, it outran light itself. That claim comes from a team led by researchers at the Technion-Israel Institute of Technology, whose study in Nature describes direct measurements of what they call optical phase singularities, tiny spots where a light wave’s amplitude falls to zero. These “dark points,” also known as vortices, are not bits of matter. They do not carry energy or information. That is why, the team says, their motion can appear to exceed light speed without violating Einstein’s limit. The work confirms a theoretical idea dating back to the 1970s. Physicists had long predicted that singularities inside wave fields could show extreme, even formally unbounded, velocities, especially when pairs of opposite-charge singularities are created or annihilated. Until now, that prediction had remained out of experimental reach. UTEM illustration (a) and image (b) illustrating the microscope column, electron spectrometer and detectors, optical setup, …
