E=mc², Einstein’s most famous equation, has been etched into the minds of millions, but what does it really mean? Few understand the profound implications hidden within this iconic formula. This video ...

The speed of light is 299,792,458 meters per second and that constant tells us much about cause and effect in the universe.

The mind-bending concept of time dilation results from a seemingly harmless assumption—that the speed of light is the same for all observers.

Light is faster than anything else in the known universe, though its speed can change depending on what it's passing through.

Thanks to the effects of relativity, a light-speed traveler experiences less time passing than an observer on Earth.

There's nothing faster than the speed of light. So, what would happen if a human managed to move at this universal speed limit?

In science fiction, spaceships moving at or beyond lightspeed enable all manner of universal exploration. But in Earth-bound reality, traveling at the speed of light (299,792,458 meters per second ...

If an object could reach the speed of light, it would become infinitely massive and would require infinite energy to maintain that speed. — How long could you survive in space without a spacesuit?