Did you know you've been cooking your food with light? Most of us have a microwave oven in our kitchens, and that's exactly what they do. When you press start, a device called a magnetron emits a ...

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 ...