On one hand, the speed of light is just a number: 299,792,458 meters per second. And on the other, it’s one of the most important constants that appears in nature and defines the relationship of ...

Imagine you’re in a car driving across the country watching the landscape. A tree in the distance gets closer to your car, passes right by you, then moves off again in the distance behind you. Of ...

The universe has a speed limit, and it's the speed of light. Nothing can travel faster than light — not even our best spacecraft — according to the laws of physics. So, what is the speed of light?

Scientists pushed photons across the universe to test the speed of light—and found Einstein’s cosmic speed limit still holds ...

The speed of light varies in materials, impacting fiber optics, laser systems, and semiconductor lithography through complex electromagnetic interactions.

Breakthroughs, discoveries, and DIY tips sent six days a week. Terms of Service and Privacy Policy. Back in 2018, astronomers examining the ruins of two collided ...

The principle of relativity, as initially described by Galileo, posits that the laws of physics remain consistent regardless of an observer's relative motion. Einstein's special relativity ...

Curious Kids is a series for children of all ages. If you have a question you’d like an expert to answer, send it to curiouskidsus@theconversation.com. Why does time change when traveling close to the ...