Here's why:

* Atmosphere vs. Space: The atmosphere is a layer of gases surrounding Earth. Space begins where the atmosphere ends, about 100 kilometers (62 miles) above Earth's surface.

* The Moon's Location: The moon orbits Earth, meaning it's in space, far beyond our atmosphere.

* Gravity: The moon is held in orbit by Earth's gravity, but it's not within the gravitational pull of our atmosphere.

We can see the moon because light from the sun reflects off its surface.