Why does the moon change shape?
Moon's Dress-Up Dance
Why does the moon change shape?
Look up tonight. The moon might be a perfect circle, or a skinny sliver, or something in between. Tomorrow night? It'll look different. The moon seems to change its shape, night after night, like it's playing dress-up in the sky.
Here's the secret: the moon isn't actually changing shape at all. It's a ball of rock, round as a marble, and it stays round every single night. What changes is how much of the sunny side we can see from Earth.
