Science: The Fun of Going Faster-than-Light

... even though you can't go faster than the speed of light in vacuum, there's no law saying you always need to be in a vacuum. So what can we do? Perhaps we can create a particle (like an electron) in some nuclear reaction that's moving close to the speed of light in vacuum, and then make it enter a medium, like water, glass, or acrylic!

What happens now, if the particle -- moving slower than c -- goes faster than light in some medium?

Amazingly enough, the particle freaks out, and starts emitting light.

The light is very special, and comes off in a particularly cone-like shape, and is the particle's way of trying to shed that extra energy until it gets down safely below the speed of light! The light is called ... Cherenkov radiation ... after its Nobel-prize-winning discoverer.

For much more, see The Fun of Going Faster-than-Light by Ethan Siegel, May 18, 2011 at Starts With A Bang!.