Max's Moon Machine

Hi, I'm Max! 👋

Hey, I'm Max! Here is a thing almost everybody gets wrong. The Moon does not change shape, and it is not Earth's shadow falling on it either. The Sun is over on the left, and it lights up exactly half of the Moon, all the time, forever — same as it lights up half of the Earth. That never changes. What changes is where we are standing. Drag the Moon around the circle and watch the picture underneath, because that one is you, outside at night, looking up. When the Moon is on the far side we get to see its whole lit half, and that's a full Moon. When it's over between us and the Sun, the lit half is pointing away from us and we see nothing at all. Everything in between is us catching part of the lit half at an angle. Drag it slowly. Watch both pictures at once. That's the whole trick.