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 ...

Light is faster than anything else in the known universe, though its speed can change depending on what it's passing through. When you purchase through links on our site, we may earn an affiliate ...

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 ...

Breakthroughs, discoveries, and DIY tips sent every weekday. Terms of Service and Privacy Policy. Back in 2018, astronomers examining the ruins of two collided ...

A pair of orbiting black holes millions of times the Sun’s mass perform a hypnotic pas de deux in a new NASA visualization. The movie traces how the black holes distort and redirect light emanating ...

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 ...

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 biggest issue you'd face is reaching that speed in the first place. When you purchase through links on our site, we may earn an affiliate commission. Here’s how it works. In science fiction, ...