We wouldn’t notice. Or we’d die. Depends on how much it changed. Relativity already tells us what would happen if the speed of light were to change, and the answer is nothing. Consider a stationary ...

On one hand, the speed of light is just a number: 299,792,458 meters per second. And on the other, it’s one of the most important constants that appears in nature and defines the relationship of ...

In the realm of physics, the speed of light is considered one of the most fundamental constants in the universe, dictating the structure of time and space as we know it. But what if this cornerstone ...

Sam Baron receives funding from the Australian Research Council. Hi Devanshi! Thanks for this great question. As far as we know, it’s not possible for a person to move at twice the speed of light. In ...

Chris Impey receives funding from the National Science Foundation and the Hearst Foundation. Curious Kids is a series for children of all ages. If you have a question you’d like an expert to answer, ...

The principle of relativity, as initially described by Galileo, posits that the laws of physics remain consistent regardless of an observer's relative motion. Einstein's special relativity ...

The speed of light in vacuum, commonly denoted c, is a universal physical constant important in many areas of physics. Its exact value is defined as 299792458 metres per second (approximately 300000 ...

In 1999, a Danish physicist named Lene Hau did the unthinkable. She slowed the speed of light. It was a remarkable move that completely changed our idea of universal constants. Since then, Hau has ...

Forbes contributors publish independent expert analyses and insights. The Universe is out there, waiting for you to discover it. One of the fundamental rules we all learn in physics — set forth by ...