The Moon, Preserving Earth's Origin Story

Why We Study Moon

From 1969 to 1972, 12 astronauts walked on the Moon as part of NASA’s Apollo program. Humans have not been back since, and the Moon remains the only world besides Earth we’ve ever visited. The Moon lacks an Earth-like atmosphere, and there is no wind or water to erase the Apollo astronauts’ footprints. The paths they walked can still be seen from orbit—permanent monuments to one of humanity’s greatest achievements.

The Moon’s lack of air and lack of plate tectonics make it a geological time capsule. The surface bears the scars of meteorites, lava flows, and the late heavy bombardment, an event roughly 4 billion years ago where the inner solar system was pummeled by asteroids and comets. We know that life arose on Earth shortly thereafter, so understanding what happened during this period of solar system history is a critical piece of our origin story.

There is water ice hidden in permanently shadowed craters at the Moon’s poles. Studying the ice could help us understand where our own planet’s water came from. The ice is also a potential resource for future human explorers: it could be harvested for breathable air, drinking water, and rocket propellant. How much water does the Moon have? Based on data from India’s Chandrayaan-1 spacecraft and NASA’s Lunar Reconnaissance Orbiter, scientists estimate the poles may have more than 600 billion kilograms of water ice, enough to fill at least 240,000 Olympic-sized swimming pools. Learn more in our guide to water on the Moon.

The Moon’s proximity to Earth makes it a natural focus of many public and private human spaceflight efforts, including NASA’s Artemis program, which seeks to land humans on the south pole in 2024. Sending astronauts to the lunar surface can help us develop and prove the viability of technologies needed for deep space exploration, including missions to Mars.