Why doesn't the Moon just fall down onto us?

Earth is tugging the Moon toward us right now — the very same pull that drops a ball to the floor. So why has the Moon hung up there for billions of years instead of crashing down? Let's let it go and watch.

1Two things happening at once

Earth pulls — and the Moon coasts sideways

You only need two ideas, and they're fighting for the Moon at the same time. Watch each one:

Gravity pulls (always toward Earth)

Earth tugs everything toward it — a dropped apple, you, and the Moon too. The pull is real all the way out there. It never stops and never runs out.

A glide keeps gliding

Once something's moving sideways, it keeps going unless something stops it. Out in space nothing rubs on the Moon, so its sideways glide never slows down.

2Same pull, two endings

Drop it straight vs. fling it sideways

Gravity tugs exactly the same in both pictures. The only difference is whether the Moon is moving sideways when it lets go:

No sideways glide

Straight down → splat

Gravity is the only thing acting, so the Moon drops straight in and smacks into Earth — like a rock you let go of.

Gliding sideways too

Falls — but keeps missing

It still falls, but it's sliding sideways so fast that Earth curves away before it lands. It falls and misses, over and over.

3Your turn — bend the falling path

Slide the sideways speed and watch the path it would fall on

Here's the Moon, way out from Earth, about to be let go. Drag the slider to give it more sideways speed and watch how gravity bends the dotted falling path. This just shows the shape of the path — you'll actually launch it in the next step.

Sideways speed: a gentle nudge
NONESUPER FAST
With no sideways speed at all, the path points straight at Earth.

4Now let it go and watch

Gravity is pulling the Moon toward us right now. Why doesn't it hit us? 🌙

Time to stop previewing and actually release the Moon. Pick a sideways speed, tap let go, and watch where it really ends up. But guess first.

Guess before you let go

Gravity is tugging the Moon straight at Earth this very second. So why doesn't the Moon come crashing down on us?