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 ...

The speed of light is a fundamental constant, approximately 299,792,458 meters per second. It's the same for all observers and hasn't changed measurably over billions of years. Nothing can travel ...

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 ...

I don’t know, ask Erwin Schrödinger. He was a relative of mine on my mother’s side. He told her mum, but she couldn’t understand it either. We’ve been in the dark ever since. The laws of the universe ...

Light is the fastest-moving thing in the universe. So what would happen if the speed of light were much, much slower? In a vacuum, the speed of light is about 186,000 miles per second (300,000 ...

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 ...

In 1676, by studying the motion of Jupiter's moon Io, Danish astronomer Ole Rømer calculated that light travels at a finite speed. Two years later, building on data gathered by Rømer, Dutch ...

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 ...