There are at least 61 natural satellites of planets in the Solar System. Each moon is much smaller than its planet.

Earth's Moon is one of the larger natural satellites with a diameter of 2,160 miles. It is the only moon close enough to us that details of its surface can be seen through a telescope from Earth.

Largest. The largest moon is Ganymede with a diameter of 3,280 miles. That means that Ganymede is even larger than either of the major planets Mercury and Pluto. Saturn's moon Titan, shown at left in a Voyager 2 photo, is the second largest moon in the Solar System with a diameter of 3,200 miles. That's twice the size of Earth's Moon.

Smallest. The smallest moon is Deimos, one of two moons of Mars. Deimos is only seven miles in diameter. It's possible there are smaller shepherd moons yet to be counted and named in the rings around Saturn and other giant gas planets in the outer Solar System.

Charon is the moon closest in size to its planet, Pluto. Earth's Moon is second in that comparison.

Moons of the Solar System
PLANET	MOONS	MOON NAMES
Mercury	0
Venus	0
Earth	1	Moon
Mars	2	Phobos, Deimos
Jupiter	61	Io, Europa, Ganymede, Callisto, Amalthea, Himalia, Elara, Pasiphae, Sinope, Lysithea, Carme, Ananke, Leda, Metis, Adrastea, Thebe, Callirrhoe, Themisto, Kalyke, Iocaste, Erinome, Harpalyke, Isonoe, Praxidike, Megaclite, Taygete, Chaldene, Autonoe, Thyone, Hermippe, Eurydome, Sponde, Pasithee, Euanthe, Kale, Orthosie, Euporie, Aitne, plus 23 to receive names
Saturn	31	Titan, Rhea, Iapetus, Dione, Tethys, Enceladus, Mimas, Hyperion, Prometheus, Pandora, Phoebe, Janus, Epimetheus, Helene, Telesto, Calypso, Atlas, Pan, Ymir, Paaliaq, Siarnaq, Tarvos, Kiviuq, Ijiraq, Thrym, Skadi, Mundilfari, Erriapo, Albiorix, Suttung plus 1 to receive a name
Uranus	27	Cordelia, Ophelia, Bianca, Cressida, Desdemona, Juliet, Portia, Rosalind, Belinda, Puck, Miranda, Ariel, Umbriel, Titania, Oberon, Caliban, Sycorax, Prospero, Setebos, Stephano, Trinculo, plus 6 to receive a name
Neptune	13	Triton, Nereid, Naiad, Thalassa, Despina, Galatea, Larissa, Proteus, plus 5 to receive names
Pluto	1	Charon
TOTAL	136

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Solar System:	The Sun
Inner System:	Mercury	Venus	Earth	Mars
Outer System:	Jupiter	Saturn	Uranus	Neptune	Pluto
Other Bodies:	Moons	Rings	Asteroids	Comets

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