What Is a Lunar Eclipse Exactly?

A lunar eclipse is when the Moon gets covered by Earth’s shadow, like a giant cookie being dipped into a cup of chocolate sauce.

Imagine you and your friend are playing with flashlights in a dark room. You’re holding the flashlight, shining light toward your friend, who’s pretending to be the Moon. Now, if you move between you and your friend, you block some of the light, making your friend look darker or even disappear for a bit. That's what happens during a lunar eclipse.

• The Sun is like your flashlight.
• The Earth is like you, standing between the Sun and the Moon.
• The Moon is like your friend, getting shaded by Earth’s shadow.

Sometimes, when Earth moves just right, it blocks the sunlight that usually shines on the Moon. That makes the Moon look darker, or even red, like a glowing fruit, because some light still bends around Earth.

A lunar eclipse only happens during a full moon, when the Sun, Earth, and Moon are all lined up just right. It’s like when your friend is farthest from you in the room, that’s when the shadow is biggest and most dramatic.