The speed of light *isn’t* the same in all media. When people refer to “the speed of light” they’re usually referring to the speed of light *in a vacuum*, which is the maximum speed at which information can travel. But light traveling through air or water or whatever will be slower than light moving through a vacuum. Usually not by much and the exact speed varies depending on the material, but slower nonetheless.
There’s also an interesting phenomenon called Cherenkov radiation, which occurs when a particle is moving through a medium faster than the speed of light in that medium. It happens in some nuclear reactors and causes a blue glow. A particle can *never* move faster than light in a vacuum, but in some mediums they can.
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