Search results
The Earth and the Moon form the Earth-Moon satellite system with a shared center of mass, or barycenter. This barycenter is 1,700 km (1,100 mi) (about a quarter of Earth's radius) beneath the Earth's surface. The Moon's orbit is slightly elliptical, with an orbital eccentricity of 0.055. [1]
- Lunar phase
As the Moon waxes (the amount of illuminated surface as seen...
- Origin of the Moon
The origin of the Moon is usually explained by a Mars-sized...
- Lunar phase
As the Moon waxes (the amount of illuminated surface as seen from Earth increases), the lunar phases progress through the new moon, crescent moon, first-quarter moon, gibbous moon, and full moon phases.
The origin of the Moon is usually explained by a Mars-sized body striking the Earth, creating a debris ring that eventually collected into a single natural satellite, the Moon, but there are a number of variations on this giant-impact hypothesis, as well as alternative explanations, and research continues into how the Moon came to be formed.
The Moon is Earth's only natural satellite. We usually see it in the night sky and also during the day. Some other planets also have moons or natural satellites. Our moon is about one-fourth of the width of the Earth. Because it is far away it looks small, about half a degree wide. The gravity on the moon is one-sixth of the Earth's gravity.
Learn about Earth's Moon, its origin, phases, weather, and more from NASA's official website. Find out how to observe the Moon, explore its surface, and discover its secrets.
Learn about the Moon's origin, structure, surface, orbit, phases, and potential for life. Explore the Moon's history, missions, and curiosities with NASA's science and visualizations.
The Moon is Earth's only natural satellite. It orbits at an average distance of 384,400 km (238,900 mi), about 30 times the diameter of Earth. Tidal forces between Earth and the Moon have over time synchronized the Moon's orbital period with its rotation period at 29.5 Earth days, causing the same side of the Moon to always face Earth.
