The Moon's diameter is 3,474 km, which is a little over a quarter of the diameter of the Earth. Due to its smaller size and mass, the pull of gravity on the lunar surface is about 17% of that at the Earth's surface. To learn more about the Moon explore this page.
The Moon is the brightest thing in the night sky when its whole face is showing, but this only happens once every 29 days, for the rest of the time we see different phases of the Moon. This happens as the Moon orbits the Earth.
The Moon also causes the rise and fall in sea levels every day, called tides. Explore more about this below.