Interesting Facts About The Other Moons In The Solar System

We only know the Moon on our planet Earth, but we don’t know much about the other moons in the solar system. But these moons are far more interesting and fascinating that you’d realize — once you read amazing things about these moons on this gallery, you’d probably wish to actually explore them!


As of 2009, there are a total of 336 moons in the solar system:

– 168 orbit all major planets (except Mercury and Venus)
– 6 orbit the dwarf planets
– the rest are asteroids and many other objects that have not been yet categorized


The largest planet on the solar system has also the largest number of moons among the other planets. Jupiter has at least 67 moons, the largest being what is known as the “Galilean moons” which are named after the Greek mythological figures: Io, Europa, Ganymede (the largest moon) and Callisto.


Io is the closest moon to Jupiter, and also the first Jupiter moon to be discovered by Italian astronomer Galileo Galilei.

Io is a high-density moon which has over 400 volcanoes, making it the only celestial body in the solar system (aside from Earth) to have a volcanic activity. It is also known as the “moon of fire and ice” because of its heavy sulfur dioxide deposits. Many of Io’s volcanoes produce sulfur dioxide smoke while its extensive plains consist of frozen sulfur dioxide.


Europa is the second closest moon to Jupiter and the smallest among the Galilean moons, discovered by Galileo Galilei in 1610. Its entire surface is icy, marked by a handful of craters, some cracks and streaks. Europa’s very high reflectivity makes it one of the brightest natural satellites in the solar system.


Ganymede is the third Galilean moon and the seventh nearest moon to Jupiter. Measuring 5,262.4 kilometers in diameter, Ganymede is about the size of Mercury but has only about half of Mercury’s mass. It is the biggest moon not only of Jupiter but of the entire solar system.

This low-density, mostly icy moon is the only moon known to have its own magnetic field. This is possibly due to a convection within its liquid iron core, which is coated by a thick, icy crust. Ganymede’s body consists of equal parts of silicate rock and ice.


Callisto is the fourth and last Galilean moon. It is also the second largest Galilean moon as well as the third largest moon in the entire solar system. Callisto’s landscape has remained intact since its formation, making it the oldest natural satellite as well as the most heavily cratered object in the solar system. It is about the size of Mercury but has only about the third of Mercury’s mass.


The ringed planet has at least 62 moons, 53 of which are officially named, and eight of them are considered the planet’s major moons. They come in several different sizes, colors and formations. Saturn’s biggest moon is Titan, which is also the second biggest moon in the solar system.

Titan is Saturn’s biggest moon, which is also the second biggest moon in the solar system. This planet-like moon is the only natural satellite known to have a significant atmosphere. Titan is bigger than Mercury; it has a diameter which is 50% larger than the Earth’s moon, and has also 80% more mass.

Titan has a rocky and icy surface; the majority of its atmosphere is made up of nitrogen, while the rest leads to the formation of methane and ethane clouds as well as nitrogenic smog.


Only Mercury, Venus and the dwarf planet Ceres have no known natural satellites or moons.


Mars has two satellites, Phobos and Deimos, which are among the smallest moons in the solar system. They were both discovered by American astronomer Asaph Hall in 1877. Unlike other moons, Phobos and Deimos are irregularly-shaped moons, and believed to be captured asteroids.

Phobos is closer to Mars than Deimos, so close that it orbits faster than Mars rotates. It is one of the least bright bodies in the solar system.

Deimos, on the other hand, orbits much slower compared to Phobos. It takes Deimos 30.3 hours to orbit Mars while Phobos completes its orbit in just 7 hours and 39 minutes.


Uranus has at least 27 natural satellites, with the five largest being Puck, Miranda, Ariel, Umbriel, Titania and Oberon. These five are named after characters in the works of William Shakespeare and Alexander Pope.

Miranda orbits the closest to Uranus. Discovered by astronomer Gerard Kuiper in 1948, it has a diameter of 471.6 kilometers and a 34-hour orbital period. It is known as one of the smallest moons in the solar system to be spherical (rounded) under its own gravity.


Neptune has at least 14 moons, the largest being Triton which was discovered by William Lassell in 1846. Triton’s discovery occurred only 17 days after the discovery of the its parent planet itself. It is the only big moon which orbits in the opposite direction to its planet’s rotation on its axis. This peculiar orbital movement is called “retrograde orbit.”

Triton’s surface is largely frozen nitrogen, while its crust is mostly water ice. Its rocky core is about 2/3 of its total mass.


The dwarf planet has five known moons — Charon (the largest), Hydra, Nyx, Styx, and Kerberos.

Charon was discovered by astronomer James Christy at the United States Naval Observatory in 1978. It is a very large moon in relation to Pluto’s size so if it weren’t orbiting Pluto, Charon would have been a dwarf planet on its own right. Its surface is mostly water ice (although less volatile) unlike Pluto’s surface which mostly consists of methane and nitrogen ice. Observations suggest that Charon may possibly have ice volcanoes and ice geysers.

Like Pluto, Charon has yet to be visited by a spacecraft, with all of its observations being ground-based.