Slowing the speed of light particles, known as photons, as they travel through air was thought to be impossible.
“That the speed of light in free space is constant is a cornerstone of modern physics,” reads the study’s abstract, published Jan. 22 in the journal Science. Yet, researchers at the University of Glasgow and Heriot-Watt University slowed photons so they were several micrometers behind their time as they traveled the space of 1 meter.
Scientists already knew that photons could be slowed down as they travel through water, glass, or other such materials. But, the slowdown of the uninhibited photons was surprising. When water or glass slows light, it only slows it as the light passes through—once on the other side, traveling through air, the light resumes its normal pace.
