Researchers at the Kastler Brossel Laboratory in Paris have made the most precise measurement of one of the fundamental constants, called the fine-structure constant, providing physicists with a vital ...

The constancy of the speed of light is a pillar of modern physics, but questions persist about its absolute universality.

There was a secret inside the envelope in the hands of Stephan Schlamminger, one of the world’s leading experts in experimental tests of gravity. He appeared to be on the verge of opening the envelope ...

Angle of rotation: A light source (left) sends a beam of light through a topological insulator with an intrinsic magnetic field (centre), changing the direction of polarization by an angle that is ...

Planck’s constant is one of the most important numbers in science. It describes the relationship between the energy and frequency of an electromagnetic wave in an equation known as the Planck-Einstein ...

An experiment on the side of an extinct volcano in Mexico involving gamma rays is helping scientists answer a fundamental question in physics: Is the speed of light the same throughout the universe?

Researchers have redetermined the gravitational constant G using a new measurement technique. Although there is still a large degree of uncertainty regarding this value, the new method offers great ...

Light doesn’t always travel at the speed of light. A new experiment reveals that focusing or manipulating the structure of light pulses reduces their speed, even in vacuum conditions. A paper ...