The Moon orbits Earth in the prograde direction and completes one revolution relative to the Vernal Equinox and the stars in about 27.32 days (a tropical...

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. Over time...

spaceflight, a lunar orbit (also known as a selenocentric orbit) is an orbit of an object around Earth's Moon. In general these orbits are not circular....

A Moon landing or lunar landing is the arrival of a spacecraft on the surface of the Moon, including both crewed and robotic missions. The first human-made...

There are 146 moons with confirmed orbits, the most of any planet in the solar system. This number does not include the many thousands of moonlets embedded...

Sun or Moon diameter every 12 hours). Earth's orbital speed averages 29.78 km/s (107,200 km/h; 66,620 mph), which is fast enough to cover the planet's...

gravitational influence of two massive orbiting bodies. Mathematically, this involves the solution of the restricted three-body problem. Normally, the two massive...

one-quarter of the population of the world saw—either live or delayed—the Christmas Eve transmission during the ninth orbit of the Moon, and an estimated...

the Sun, shift. The visible side of the Moon is sunlit to varying extents, depending on the position of the Moon in its orbit, with the sunlit portion...

heliocentric orbit but rather orbit their parent object. Geocentric orbit: An orbit around the planet Earth, such as that of the Moon or of artificial satellites...