From early experiments with lanterns to Einstein’s revelations about space and time, the speed of light has proven to be far more than a number: it’s the cosmic constant that defines reality.

For science-fiction enthusiasts, that’s a bit depressing. Space is big, and while the speed of light is incredibly fast to us ...

James is a published author with multiple pop-history and science books to his name. He specializes in history, space, strange science, and anything out of the ordinary.View full profile James is a ...

Light speed would allow instant trips across Earth and minutes to reach the Sun, but even at 300,000 km/s the expanding ...

Alfredo has a PhD in Astrophysics and a Master's in Quantum Fields and Fundamental Forces from Imperial College London.View full profile Alfredo has a PhD in Astrophysics and a Master's in Quantum ...

NASA's Voyager 1 probe launched into space in 1977, shortly after the Voyager 2 probe. Since then it has continued ...

Every year, our planet makes one full trip around the Sun. And while that means we’re already moving at breakneck speeds, we’re about to ramp that speed up. Like, way up! Let’s turn Earth into a ...

Cosmic speed limits can be a major inconvenience but they've rarely stopped science fiction in its tracks. When it comes to space travel, Albert Einstein's theory of relativity is a major ...

Breakthroughs, discoveries, and DIY tips sent every weekday. Terms of Service and Privacy Policy. In science fiction, spaceships moving at or beyond lightspeed enable ...

When I was a teenager, I was—shockingly, I know—deeply nerdy. At a science-fiction convention, I bought a button that read, “186,282 miles/second: Not just a good idea, it’s the law.” It was poking ...

For a decade and a half, astronomers have been on the trail of a galactic mystery. In 2011, a project that surveyed the Milky Way galaxy for exoplanets — which are planets beyond our solar system — ...