A photon can cross a billion light-years while accumulating no elapsed time along its path. Special relativity links space ...

My telescope, set up for astrophotography in my light-polluted San Diego backyard, was pointed at a galaxy unfathomably far from Earth. My wife, Cristina, walked up just as the first space photo ...

It’s in your physics textbook, go look. It says that you can either model light as an electromagnetic wave OR you can model light a stream of photons. You can’t use both models at the same time. It’s ...

Light therapy may improve sleep by helping to regulate your circadian rhythm, promoting alertness during the day and facilitating better sleep at night. Share on Pinterest It may seem counterintuitive ...

The light-year is an indispensable unit of measurement for anyone trying to understand outer space. Get a group of astronomers talking, and you’ll hear them say “light-years” about as often as you ...

EDITOR’S NOTE: Call to Earth is a CNN editorial series committed to reporting on the environmental challenges facing our planet, together with the solutions. Rolex’s Perpetual Planet Initiative has ...

Are smart light bulbs actually as efficient as regular ones and are there considerations that can help to make the most out ...

Scientists have created an “electron lighthouse” that uses laser light to launch and steer electrons through a semiconductor without an applied electrical field. The quantum effect could eventually ...