All of the planets in our solar system have names from Greek or Roman mythology. This was continued when Uranus, Neptune, and Pluto were discovered in more modern times.
• Mercury (Hermes) is the god of commerce, travel and thievery in Roman mythology. The planet probably received this name because it moves so quickly across the sky.
• Venus (Aphrodite) is the Roman goddess of love and beauty. The planet is aptly named since it makes a beautiful sight in the sky, with only the Sun and the Moon being brighter.
• Earth (Gaia) is the only planet whose English name does not derive from Greek/Roman mythology. The name derives from Old English and Germanic. There are, of course, many other names for our planet in other languages.
• Jupiter (Zeus) was the King of the Gods in Roman mythology, making the name a good choice for what is by far the largest planet in our solar system
• Mars (Ares) is the Roman god of War. The planet probably got this name due to its red color. Jupiter was the King of the Gods in Roman mythology, making the name a good choice for what is by far the largest planet in our solar system.
• Saturn (Cronus) is the Roman god of agriculture.
• Uranus is the ancient Roman deity of the Heavens, the earliest supreme god.
• Neptune (Poseidon), was the Roman god of the Sea. Given the beautiful blue color of this planet, the name is an excellent choice!
• Pluto (Hades) is the Roman god of the underworld in Roman mythology. Perhaps the planet received this name because it’s so far from the Sun that it is in perpetual darkness.
For those moons have been known for a long time (such as the Galilean moons of Jupiter), the names were assigned from mythological characters. For example, the moons of Jupiter were named for characters who had roles in the life of Zeus (the Greek mythology counterpart of the Roman God Jupiter). For example:
• Metis (first wife of Zeus)