Einstein’s claim that the speed of light is constant has survived more than a century of scrutiny—but scientists are still daring to test it. Some theories of quantum gravity suggest light might ...

This video looks at the earliest experiments to measure the speed of light, explaining the methods, challenges, and breakthroughs that shaped our understanding of physics. Defense Department says ...

In this video I show you what it would look like to slow the speed of light down to around walking speed. So with just walking around town you would experience relativistic effects. I talk about time ...