Cosma Home > Communication > Knowledge > Realm > Physical > Universe > Star > Solar System > Planet > Moon
Spotlight
Related
Pages
Physical Universe
Galaxy, Star, Solar System, Planet, Moon, Asteroid, Comet
Mercury, Venus, Earth (Moon), Mars (3D), Jupiter, Saturn, Uranus, Neptune, Pluto
Resources
These are organized by a classification scheme developed exclusively for Cosma. More…
General
Portal
Our Solar System’s Moons (NASA), Moons (Wikipedia)
Dictionary
moon : a natural satellite of a planet — Webster
OneLook, Free Dictionary, Wiktionary, Urban Dictionary
Encyclopedia
Natural satellite or moon is a celestial body that orbits a planet or smaller body, which is called its primary. The two terms are used synonymously for non-artificial satellites of planets, of dwarf planets, and of minor planets. Of the inner planets, Mercury and Venus have no moons; Earth has one large moon, known as the Moon; and Mars has two tiny moons, Phobos and Deimos. The large gas giants have extensive systems of moons, including half a dozen comparable in size to Earth’s moon: the four Galilean moons, Saturn’s Titan, and Neptune’s Triton. Saturn has an additional six mid-sized moons massive enough to have achieved hydrostatic equilibrium, and Uranus has five. The Earth-Moon system is unique in that the ratio of the mass of the Moon to the Earth is much greater than any other planet-moon ratio in the Solar System, and the Moon’s orbit with respect to the Sun is always concave. — Wikipedia
Search
Preservation
Library
WorldCat, Library of Congress, UPenn Online Books, Open Library
Participation
News
Book
Government
Our Solar System, Moons (NASA)
Document
