How Does a Lunar Eclipse Actually Work?

A lunar eclipse happens when Earth blocks sunlight from reaching the Moon.

Imagine you and your friend are playing flashlight tag in a dark room. You're the Earth, your friend is the Moon, and the flashlight is the Sun. When you stand between your friend and the flashlight, you block the light, that’s like a lunar eclipse!

• The Sun sends out light.
• The Earth moves in front of the Moon.
• That blocks some or all of the sunlight from hitting the Moon.

Sometimes, Earth's shadow is just a bit bigger than the Moon, that’s like when you stand between your friend and the flashlight but only partly block it. Then we see a partial lunar eclipse.

Other times, Earth completely covers the Moon, like when you stand right in front of your friend so no light reaches them at all. That makes a total lunar eclipse!

You might notice the Moon turns a pretty red color during a total eclipse, that’s because some sunlight still bends around Earth and lights up the Moon, just like when you're playing flashlight tag and some light sneaks around your body!