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 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. …

6 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 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.

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

3 days ago · 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.

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 …

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.

5 days ago · If all goes according to NASA’s plans, 2026 will finally be the year that astronauts once again launch to the moon. In a matter of months, four astronauts are poised to fly around the moon …

1 day ago · The NASA Artemis II mission, set to lift off as soon as February, will mark the first time astronauts have aimed to venture beyond near-Earth orbit since 1972.