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 …

Dec 29, 2025 · Like Earth, the Moon has a day side and a night side, which change as the Moon rotates. The Sun always illuminates half of the Moon while the other half remains dark.

1 day ago · Explore the Moon Calendar: track the Moon phases, learn about lunar events, and check what the Moon will look like in the sky tonight. Perfect for astronomers and stargazers!

A Moon cycle, or a lunation, is the time the Moon travels through its lunar phases. ©timeanddate.com Your January 2026 Moon guide Skywatching tips for January 2026’s must …

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 …

The Moon: Complete and live astronomy data, visibility information, sky charts, graphs, and tools for sky-watchers at all levels.

2 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 …

NASA's interactive map for observing the Moon each day of the year.

2 days ago · Particles from Earth’s atmosphere have been carried into space by solar wind and landing on the moon for billions of years, mixing into the lunar soil, according to a new study.

The moon and sun share top billing in 2026. Kicking off the year's cosmic wonders is the moon, drawing the first astronauts to visit in more than 50 years.