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 20, 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 …

Dec 4, 2025 · What is the Moon Phase today? Use our 2023 Moon Phase Calendar to find dates and times of the full Moon, new Moon, and every phase in between. Beyond the phases of the Moon, you …

Dec 15, 2025 · Research shows a full moon can modestly affect sleep, but its influence on mental health is much less certain.

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 …

Dec 17, 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.

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

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.

The Moon phase calculator shows exact times of the various moon phases for Hyattsville, Maryland, USA in year 2024 or in other locations and years.

Dec 17, 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 in 1959. …