Why does light carry energy even though it has no mass? This video explains the real physics behind photons, energy–momentum ...

We walk here, we walk there, we walk everywhere. Maybe you’re headed to work or to lunch in a busy city. You’re expending energy, and the exercise is good for you. But what if, on top of that, we ...

"There are more questions than answers at this point." When you purchase through links on our site, we may earn an affiliate commission. Here’s how it works. Dark energy could have an accomplice that ...