IT IS ONE of the biggest mysteries in cosmology—and getting bigger all the time. Ever since Edwin Hubble, an American astronomer, published observations of distant galaxies in 1929, scientists have ...

If there is an absolute law in the universe, it’s that nothing can travel faster than the speed of light. For science-fiction enthusiasts, that’s a bit depressing. Space is big, and while the speed of ...

Here is a thought experiment for you: imagine shining a powerful laser at the moon, the beam cutting through space until it lands on its dusty grey surface. Now flick the laser so the spot of light ...

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 ...