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 ...

I'll be honest: I didn't know that an iPhone was able to do a lidar scan. (The iPhone 12 Pro, 13 Pro, and iPad Pro can all do it.) When I found out that my phone could, I became obsessed with scanning ...

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 ...

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, ...

Michael Lam does not work for, consult, own shares in or receive funding from any company or organization that would benefit from this article, and has disclosed no relevant affiliations beyond their ...

Nothing can move faster than the speed of light. When Einstein set forth his theory of relativity, this was his inviolable postulate: that there was an ultimate cosmic speed limit, and that only ...