There's an ultimate speed limit in the Universe: the speed of light in a vacuum, c. If you don't have any mass — whether you're a light wave (a photon), a gluon, or even a gravitational wave — that's ...

But don't worry, no laws of physics are being violated. When you purchase through links on our site, we may earn an affiliate commission. Here’s how it works. In a distant corner of the universe, ...