- Billiards is a good game (mag.uchicago.edu)
Michelson’s wonder was what his head did with his hands, and a few boxes and rotating mirrors. He measured things, especially things that were regarded as unmeasurable, ineffable, and precious as life itself. Among other things, he had measured light and a star. I watched him play billiards nearly every noon for several months before he retired from the University, and, in introducing myself, I could further say with equal truth, “Shake the hand that shook the hand of John L. Sullivan.” If I get the right opening, though, I prefer saying, “When young, I watched Michelson play billiards.”
- Speed of light (Wikipedia)
The speed of light in vacuum, commonly denoted c, is a universal physical constant that is important in many areas of physics. The speed of light c is exactly equal to 299,792,458 metres per second (approximately 300,000 kilometres per second; 186,000 miles per second; 671 million miles per hour). According to the special theory of relativity, c is the upper limit for the speed at which conventional matter or energy (and thus any signal carrying information) can travel through space.