Here's an example of the Cherenkov Radiation.
I read an article the other day that I thought was the coolest thing. It was about the speed of light and how it doesn't always travel very fast. In a vacuum, the speed of light is 300,000 km a second; however, light doesn't always travel in a vacuum. In water, for instance, light travels three quarters of that speed.
The article goes on to mention what I thought was super interesting. In nuclear reactors, particles can be forced up to speeds so high they are often within a fraction of the speed of light. To add on, if they are travelling through a medium that slows light down, they could potentially travel faster that light around them. That's not even the cool part.
When the particles travel faster than the speed of light, they emit a blue glow, known as "Cherenkov radiation." It's sort of comparable to a sonic boom but with light, which is why nuclear reactors glow in the dark.
Additionally, the article goes on to mention that the slowest that light has ever been recorded moving was 17 m/s, or 38 mph. I can drive a car faster than that! And if that wasn't impressive enough, they top it off by saying that light has been brought to a complete stop. I don't know about you, but personally, that's mind boggling.
Thanks for tuning in folks!