In geophysical terms, the Moon is a planetary-mass object or satellite planet. Its mass is 1.2% that of the Earth, and its diameter is 3,474 km (2,159 mi), roughly one-quarter of Earth's (about as …

3 days ago · Moon, Earth’s sole natural satellite and nearest celestial body. Known since prehistoric times, it is the brightest object in the sky after the Sun. Its name in English, like that …

Jun 25, 2025 · The Earth and Moon are tidally locked. Their rotations are so in sync we only see one side of the Moon. Humans didn't see the lunar far side until a Soviet spacecraft flew past …

We see the full moon when the sun is directly behind us, illuminating a full hemisphere of the moon when it is directly in front of us.

Nov 6, 2025 · Space agencies around the world are planning moon missions that will depend on water ice for resources, but much remains unknown about its availability of water ice on the …

What is the moon made of, and how did it form? Learn about the moon's violent origins, how its phases shaped the earliest calendars, and how humans first explored Earth's only natural …

Jun 10, 2025 · Earth’s companion has allowed astronomers to define lunar cycles, navigate without technology, and understand celestial movements.

Sep 18, 2025 · The eight lunar phases are, in order: new Moon, waxing crescent, first quarter, waxing gibbous, full Moon, waning gibbous, third quarter, and waning crescent. The cycle …

2 days ago · This, researchers hope, will help settle a long debate about whether the Moon's inner heart is solid or molten, and lead to a more accurate understanding of the Moon's history – …

A lunar phase or Moon phase is the apparent shape of the Moon 's day and night phases of the lunar day as viewed from afar. Because the Moon is tidally locked to Earth, the cycle of …