Can light travel through a vacuum

Faster than the light through the vacuum

science

US researchers exceeded the speed of light with a new method - Einstein could still not be refuted.

London - US researchers have described an experiment with which they can send light pulses through a chamber much faster than the known speed of light. The speed of light in a vacuum of 300,000 kilometers per second has long been considered unbeatable. As in earlier experiments on the speed of lightning, the new US experiment cannot refute Albert Einstein. The US researchers' trick: They developed a special material, a gas made from cold cesium atoms, in which the light pulses travel faster than in a vacuum. No contradiction to the theory of relativity The team led by L. J. Wang from the NEC research institute in Princeton (US state New Jersey) presented the experiment in the British journal Nature (Vol. 406, pp. 277-279) on Thursday. A pulse of light consists of a series of rays or waves and moves at a specific group speed. The single wave cannot get faster than the light. In the case of a composite light pulse, however, skillful influencing of the waves can lead to a higher group speed - this does not even contradict the theory of relativity. The researchers succeeded in superimposing the waves with the help of the special cesium gas. In most materials, the group speed of a light pulse is lower than that in a vacuum. If a light pulse is to travel faster than in a vacuum, a material with an unusual refractive index is required. In the cesium gas, the speed of the light waves increases with certain frequencies through interactions with the atoms. (APA / dpa)