Moons can come in many shapes and sizes. They range from large to small, solid bodies to volcanic ones, and some have atmospheres. Most planetary moons formed from the discs of gases and dust circulating in the early solar system.
There are hundreds of moons in our solar system. Even a few asteroids have been found to have small companion moons. Moons that begin with a letter and a year are considered provisional moons, as they will be given a proper name once their discoveries are confirmed by additional observations.
*Moons of planets and dwarf planets.
How Moons Get Their Names
Ancient myths, legends, and tales were handed down generation after generation, creating images of gods, heroes, and villains. Some of those myths are so well known that people still name their own children after them. Jupiter’s four largest moons are named for characters from Greek and Roman mythology: Theia (Nereid), Dione (Larissa), Europa (Callisto), and Ganymede (Enceladus).
Uranus is unique in having 11 known moons. Other than Earth, Uranus is the only planet with natural satellites that are not named for deities or places. Many of these names come from Shakespearean characters and Alexander Pope’s poetry, but some like Puck and Ariel come from a popular culture too.
Saturn has more than 20 known moons, but only four of those have names: Titan, Mimas, Enceladus and Rhea. Most are named after Titans in Greek mythology. Some of the moons were named from Star Wars movies or TV shows (Biggs, Leia). Neptune currently has 13 known moons totaling 119 objects.
Moons of the Inner Solar System
The Moon is Earth’s only natural satellite. Its rocky, iron-rich core is more than twice as dense as Earth’s mantle and crust combined, suggesting that it formed very early in the history of the inner solar system. Debris from a large body about the size of Mars colliding with Earth locked into orbit could have provided the fuel for a cataclysmic collision that formed our Moon. Scientists have stated that there is a one in 10,000 chance that all of the material making up the Moon came from other sources.
While the Moon is often depicted as a spherical object, its two most prominent moons are lumpy and uneven. Phobos, which orbits closer to Mars than any other moon in the solar system besides Earth’s Moon, could crash into its planet in less than 100 million years. The smaller Deimos is a mile across but approaches Mars at less than a third of our moon’s distance from Earth.
Moons of the Giant Planets
Jupiter’s menagerie of moons includes the largest in the solar system, Ganymede. One of Jupiter’s outer moons, Europa, is believed to have an ocean beneath its icy surface. Another moon (Io), is a volcanic moon that spews forth gases and ices from volcanoes. Saturn has two ocean moons – Enceladus and Titan. Both have subsurface oceans, and Titan also has surface seas of lakes of ethane and methane.”
There are many moons orbiting Jupiter, ranging from the tiny Mimas that orbits within the orbit of Europa, to the massive Ganymede that is larger than our moon. Other moons such as Callisto and Iapetus can be seen in the telescope as small black spots, as well as a small moonlet known as Puck.
Moons of Dwarf Planets
Pluto’s large moon Charon is about half the size of Pluto. Scientists using the Hubble Space Telescope to study Pluto found four more small moons. Eris, another dwarf planet even more distant than Pluto, has a small moon of its own: Dysnomia. Haumea, another dwarf planet, has two satellites: Hi’iaka and Namaka. Ceres has no moons.
Scientists using the Hubble Space Telescope to study Pluto found four more small moons. The largest is about 630 miles wide, but scientists think that Charon is actually a remnant from an even earlier collision with an impactor. And if it’s not a remnant of that event, then it must be because everything in our solar system formed from the same basic material.