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 ...

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 ...

The glow from faster-than-light particles gives us a unique way to explore the universe. Nothing can travel faster than light — in a vacuum. But when light slows down, sometimes matter can blaze past ...

How do we know the speed of light – and why does it have a speed limit at all? Leah Crane explores the history of one of the ...

The familiar claim, “Nothing can go faster than light,” is, in fact, misleading. Light travels at different speeds in different media. The speed depends on the medium’s index of refraction (n). Light ...

The speed of light is one of the most fundamental constants in physics and an enduring source of fascination for scientists and curious minds alike. At approximately 299,792 kilometres per second in a ...

The universe has a speed limit, and it's the speed of light. Nothing can travel faster than light — not even our best spacecraft — according to the laws of physics. So, what is the speed of light?

James is a published author with multiple pop-history and science books to his name. He specializes in history, space, strange science, and anything out of the ordinary.View full profile James is a ...

We explore the difference between the constant speed of light in a vacuum and its slower group velocity in dense mediums ...

Alfredo has a PhD in Astrophysics and a Master's in Quantum Fields and Fundamental Forces from Imperial College London.View full profile Alfredo has a PhD in Astrophysics and a Master's in Quantum ...

Simply put, if I were to shine a beam of light between two plates that were close enough to exhibit the attraction of the Casimir effect, would the speed of light as it travels parallel to the plates ...