What happens if you do a big jump? Your body goes up into the air. But then it comes back down again. The reason you don’t just keep going up, up, up is because the force of gravity pushes your body ...

Let's turn the sun into a telescope. In fact, we don't have to do any work—we just have to be in the right spot. But how can the sun be a telescope? The sun is not a mirror, but it is a lens. And we ...