The Moon is Earth's only natural satellite.
The average distance from the Earth to the Moon is 384,399 kilometres (238,854 mi), which is about 30 times the diameter of the Earth.
At this distance, it takes sunlight reflected from the lunar surface approximately 1.3 seconds to reach Earth.
The Moon's diameter is 3,474 kilometres (2,159 mi), which is about 3.7 times smaller than the Earth, making it the Solar System's fifth largest moon, both by diameter and mass, ranking behind Ganymede, Titan, Callisto, and Io.
Geosynchronous orbit A geosynchronous orbit is a geocentric orbit that has the same orbital period as the sidereal rotation period of the Earth. It has a semi-major axis ... >
read more
Deimos (moon) Deimos is probably an asteroid that was perturbed by Jupiter into an orbit that allowed it to be captured by Mars, though this hypothesis is still in ... >
read more
Phobos (moon) Phobos is the larger and innermost of Mars' two moons, and is named after Phobos, son of Ares (Mars) from Greek Mythology. Phobos orbits closer to a ... >
read more
Precession Precession refers to a change in the direction of the axis of a rotating object. In certain contexts, "precession" may refer to the precession that ... >
read more
Neptune's natural satellites Neptune has 13 known moons. The largest by far is Triton, discovered by William Lassell just 17 days after the discovery of Neptune itself. It took a ... >
read more
Dysnomia (moon of Eris) Dysnomia, is a moon of the dwarf planet Eris. The satellite is about 60 times fainter than Eris, and its diameter is estimated to be approximately ... >
read more
Saturn Saturn is the sixth planet from the Sun. It is a gas giant, the second-largest planet in the solar system after Jupiter. Saturn has a prominent ... >
read more
Mercury (planet) Mercury is the innermost and smallest planet in the solar system, orbiting the Sun once every 88 days. It ranges in brightness from about −2.0 ... >
read more
Uranus Uranus is the seventh planet from the Sun. It is a gas giant, the third largest by diameter and fourth largest by mass. NASA's Voyager 2 is the only ... >
read more
Shift of equinox The precession of the equinoxes refers to the precession of Earth's axis of rotation with respect to inertial space. The precession of the equinoxes ... >
read more