The Moon: Why Does It Glow If It Isn't a Star?

The moon doesn't have fire, lava, or electricity to make its own light. Instead, it acts like a giant, dusty mirror in the sky. It catches the powerful light coming from the sun and bounces it down to Earth. This reflected light is what we call 'moonlight,' even though it really started at the sun.

The moon seems to change shape because it orbits the Earth. We only see the part of the moon that is currently being lit up by the sun. When the sun is 'behind' the moon from our view, the side facing us is dark—that's what we call a New Moon.

Have you ever seen a crescent moon where the 'dark' part is faintly visible? That is called 'Earthshine.' It happens because sunlight bounces off the Earth, hits the moon, and then bounces back to your eyes. It’s a double-bounce of light that lets us see the moon's shadow!