And that is absolutely 100% accurate, with no measurement errors. But Jack, I hear you say, what are you talking about? The reason we know that that's exactly the speed of light, is that we defined it ...

When Galileo's name comes up, most people think about his contributions to observational astronomy. However, he did lots of other stuff including investigating the speed of light. During his time, ...

The motion of any object is relative. On Earth we tend to ignore that, because the vast background of the ground gives us a seemingly fixed and absolute frame of reference. Sitting comfortably at our ...

Special relativity is one of the most strongly validated theories humanity has ever devised. It is central to everything from space travel and GPS to our electrical power grid. Central to relativity ...

You might think that if you have a need to measure the speed of a projectile that is too fast for your high-speed camera, you would have to invest in some significantly expensive equipment. That was ...

There’s a simple way to measure the speed of sound. It’s low tech and unimpressive, but you get to blast an air horn. How many times can you say that you’re using one for science and not sheer ...