The Moon

From lighting up our skies to maintaining a geological record of our solar system’s history, Earth’s closest celestial neighbor plays a pivotal role in the studies of our planet and our solar system. 

blue Earth against a black sky above the barren lunar surface

About earth's moon

nearly full moon, with some far side features visible

The Moon is about 27% the size of Earth.

Illustration of the Moon and its orbit around Earth.

We always see the same side of the Moon.

Mountain in the middle of Moon crater

The Moon has a solid, rocky surface.

astronaut with u.s. flag

There's no rain or wind, but there is weather.

Astronaut and robotic spacecraft on the Moon.

24 humans and more than 100 robots visited.

Overview

Earth's Moon is the brightest and largest object in our night sky. The Moon makes Earth a more livable planet by moderating our home planet's wobble on its axis, leading to a relatively stable climate. It also causes tides, creating a rhythm that has guided humans for thousands of years.

The Moon was likely formed after a Mars-sized body collided with Earth several billion years ago.

Earth's only natural satellite is simply called "the Moon" because people didn't know other moons existed until Galileo Galilei discovered four moons orbiting Jupiter in 1610. In Latin, the Moon was called Luna, which is the main adjective for all things Moon-related: lunar.

This visualization shows the Moon's phase at hourly intervals throughout 2024, as viewed from the Northern Hemisphere.
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