The Moon is Earth ’s sole natural satellite and nearest large celestial body. It is a spherical rocky body, probably with a small metallic core, revolving around Earth in a slightly eccentric orbit at a mean distance of about 384,000 km (238,600 miles). Its equatorial radius is 1,738 km (1,080 miles). Because of the Moon’s small size and mass, its surface gravity is only about one-sixth of Earth’s.

Moon

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Interactive: A Tour of the Moon's Landmarks.

Look at the 3D map of the Moon as taken by the Clementine spacecraft

geometry and motions of the Earth-Moon system

Why does the Moon always face Earth the same way?

For Students

Moon summary

Moon

Q: Should humans colonize the Moon?

Space colonization, on the Moon or elsewhere, is widely debated. Some argue that humans have a moral duty to save our species from extinction, and space colonization is one way of doing so. Others argue that living in space is science fiction and that we should concentrate on improving life on Earth instead of potentially ruining another planet or moon. For more on the debate about colonizing space, visit ProCon.org .

Earth’s satellite

Written by James D. Burke

Fact-checked by The Editors of Encyclopaedia Britannica

Last Updated: Jan 21, 2025 • Article History

What is the Moon?

Should humans colonize the Moon?

News •

World Monuments Fund adds Moon, Apollo 11 sites to 2025 heritage preservation watch list • Jan. 18, 2025, 9:09 PM ET (Jerusalem Post)

Moon added to list of vulnerable sites by World Monuments Fund • Jan. 18, 2025, 2:29 AM ET (CNN)

Moon placed on World Monument Fund list of heritage sites in need of protection • Jan. 17, 2025, 3:04 AM ET (ABC News (Australia))

Moon added to list of threatened cultural sites; ‘mounting risks amidst accelerating lunar activities’, says WMF chief • Jan. 16, 2025, 7:53 AM ET (The Indian Express)

SpaceX rocket launches private missions to the Moon • Jan. 15, 2025, 2:29 AM ET (BBC)

Moon, Earth’s sole natural satellite and nearest large celestial body. Known since prehistoric times, it is the brightest object in the sky after the Sun. It is designated by the symbol ☽. Its name in English, like that of Earth, is of Germanic and Old English derivation. The Moon’s desolate beauty has been a source of fascination and curiosity throughout history and has inspired a rich cultural and symbolic tradition. In past civilizations the Moon was regarded as a deity, its dominion dramatically manifested in its rhythmic control over the tides and the cycle of female fertility. Ancient lore and ...(100 of 10458 words)

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