The Moon

Our Moon. Look for it tonight and see what shape it is. The Moon is slowly drifting away from Earth — about 4 cm every year! About the same as the speed of a growing fingernail.

Also called: the moon tonight.

🕒 When can I see it?🚀 Travel there

What it is

Earth's only natural satellite, rocky, cratered, likely formed from a giant impact on early Earth.

Moon: Orbits a planet rather than the star. Every kind of thing there is →

How to find the Moon

Its position moves, so there is no fixed place on a map to point at. The Planetarium works out where it is for your own place and date.

Show me the Moon in tonight's sky

What you will really see

With your own eyes

The easiest thing in the sky — watch its shape change night after night.

Through a small telescope

The best first target — craters, dark "seas" and mountains, sharpest along the day/night line.

🔭 See it drawn as it looks through a telescope

🖨️ A sheet to print for this

🖨️ Print a sheet and go and look

🖨️ Sheet to take outside →

Worth knowing about the Moon

The Moon is about a quarter the width of Earth — a tennis ball held next to a basketball. In weight, very light compared to Earth. Light crosses from Earth to the Moon in 1.3 seconds. Its day: it turns once for every trip round us, so the same face always looks our way. Nobody saw the other side until a spacecraft went round the back in 1959.

Its surface: Rocky, heavily cratered, no atmosphere, likely formed when something huge smashed into early Earth.
How it moves: About one month — matches the Moon phases you see in the sky.
The machines we sent: Apollo 11 (1969) — first humans to walk on another world.
What makes it worth knowing: Gravity is only 1/6 of Earth's, so a 30 kg kid would feel like they weigh about 5 kg — astronauts couldn't walk normally and instead had to bounce along in low, springy hops. Because there's no wind, rain, or air to erode anything, footprints left on the Moon could stay there essentially unchanged for millions of years.

How did anyone measure the Earth in the first place?

The numbers

Across	3 475 km
Distance from Earth	384 400 km
Once round its orbit	27.3 days
One spin	27.3 days
Made of, among other things	water, rock (basalt)

How anyone knows this

Nobody flew a tape measure out there. Every number on this page was worked out from the ground:

What it belongs to

☀️ Everything the Sun holds, in one place 📖 How the solar system fits together

Then go outside

Clear tonight? The Planetarium will show you what is worth a look. Then just go out.

🌙 Plan an evening outside 🌌 Everything else in the sky