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Minute Earth (YouTube) & Minute Physics (YouTube)


moon : a natural satellite of a planet — Webster   See also   OneLook


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

Moons Category (Wikipedia)
Moon, Natural Satellite (Encyclopædia Britannica)




European Space Agency, ESA (YouTube Channel)

Solar System Exploration: Moons (JPL, NASA)
Satellites of Outer Planets (Minor Planet Center, International Astronomical Union)
Natural Satellites (WolframAlpha)

Exomoon or extrasolar moon is a natural satellite that orbits an exoplanet or other non-stellar extrasolar body. It is inferred from the empirical study of natural satellites in the Solar System that they are likely to be common elements of planetary systems. The majority of detected exoplanets are giant planets. In the Solar System, the giant planets have large collections of natural satellites (see Moons of Jupiter, Moons of Saturn, Moons of Uranus and Moons of Neptune). Therefore, it is reasonable to assume that exomoons are equally common. — Wikipedia

NASA Goddard (YouTube Channel)

Astronomers Find First Evidence of Possible Moon Outside Our Solar System (NASA)
Evidence for a large exomoon orbiting Kepler-1625b (Alex Teachey and David M. Kipping, Science Advances)




WorldCat, Library of Congress, UPenn Online Books, Open Library




MooMooMath and Science (YouTube Channel)

MERLOT: Multimedia Educational Resource for Learning and Online Teaching
OER Commons: Open Educational Resources


Moons (
Moons (NPR Archives)



Moons (




Explore related posts on Cosma


Here are links to pages about closely related subjects.

Knowledge Realm


Law (Constant) Relativity
Force Gravity, Electromagnetism (Light, Color)
Matter (Microscope) Molecule, Atom (Periodic Table), Particle

Universe (Astronomical Instrument)
Galaxy Milky Way, Andromeda
Planetary System Star, Brown Dwarf, Planet, Moon

Our Neighborhood
Solar System Sun
Terrestrial Planet Mercury, Venus, Earth (Moon), Mars
Asteroid Belt Ceres, Vesta
Jovian Planet Jupiter, Saturn, Uranus, Neptune
Trans-Neptunian Object
Kuiper Belt Pluto, Haumea, Makemake
Scattered Disc Eris, Sedna, Planet X
Oort Cloud Etc. Scholz’s Star
Small Body Comet, Centaur, Asteroid


1.   The resources on this page are are organized by a classification scheme developed exclusively for Cosma.