Light travels fast. Very fast. So much so, that it just seems instant to us. But, for the first time ever, we can see for ourselves that it isn’t and that it does indeed travel.
Researchers at the Heriot-Watt University in Edinburgh have managed to capture a laser beam travelling through the air for the first time. In the video bellow, which was recorded at 20 billion frames per second and lasts 6 nanoseconds, we see the laser beam coasting through the air, with the protons of the beam reflecting off particles in the atmosphere.
Source: The Verge