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 wide as the …

Dec 26, 2025 · 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 of Earth, is of …

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.

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

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 satellite half a …

Nov 19, 2021 · What Is the Umbra? The umbra is the dark center portion of a shadow. The Moon's umbra causes total solar eclipses, and the Earth's umbra is involved in total and partial lunar eclipses.

4 days ago · With our 2026 Moon Phase Calendar, you'll find the current Moon phase for tonight—plus, all the phases of the Moon for each day of the month.

Dec 29, 2025 · The Moon makes Earth more livable, sets the rhythm of ocean tides, and keeps a record of our solar system's history. Explore NASA lunar science here.

Explore the current phase of the moon, its rise and set times, nightly motion across the sky, and discover lunar features with our interactive map. Stay informed about the celestial movements above.

Dates of Primary Phases of the Moon This data service calculates the primary phases of the moon for years between 1700 and 2100. Specify the year, the number of phases, and the data format in the …