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 ...

(via PBS Space Time) One of the most fundamental physics facts is that the speed of light in a vacuum is constant for all observers. But can we really be sure that the speed of light wasn’t different ...

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 ...

The hyperdrive from Star Wars appears to depict an ultra-relativistic motion through space, extremely close to the speed of light. Under the laws of relativity, you neither reach nor exceed the speed ...

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 ...

Here, a calcite crystal is struck with a laser operating at 445 nanometers, fluorescing and displaying properties of birefringence. Unlike the standard picture of light breaking into individual ...

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 ...

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 ...

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, ...

In 1887 one of the most important experiments in the history of physics took place. American scientists Michelson and Morley failed to measure the speed of the Earth by comparing the speed of light in ...