The names of the planets in our solar system are drawn primarily from classical mythology. While the vast majority are named after Roman gods and goddesses, this convention has one notable exception. The discovery of the seventh planet led to a singular departure from the otherwise consistent Roman naming scheme.
Understanding the Solar System’s Naming Scheme
The first five planets visible to the naked eye were known to ancient observers and were systematically named according to Roman mythology. This naming convention became the standard because Roman culture was the dominant reference point in the Western world when astronomical bodies were first cataloged. The tradition links the planets’ characteristics, such as their movement or appearance, to the attributes of the Roman deities.
Mercury, the fastest planet to orbit the Sun, was named after the Roman messenger god, who was known for his swiftness. Venus, the brightest object in the sky after the Sun and Moon, was named for the Roman goddess of love and beauty. Mars, with its distinct reddish hue, was named after the Roman god of war, a color often associated with conflict and blood.
Jupiter is named after the king of the Roman gods, who ruled the sky and thunder. Saturn, which orbits more slowly, was named for the Roman god of agriculture and time, who was also Jupiter’s father.
Uranus: The Planet Named After a Greek Primordial Deity
The tradition of Roman naming was broken in 1781 with the discovery of the seventh planet by astronomer William Herschel. Initially, Herschel wanted to name the new body Georgium Sidus, or “George’s Star,” in honor of his patron, King George III of Great Britain. This choice, however, was unpopular among astronomers in other European countries who preferred a name that continued the mythological theme.
German astronomer Johann Elert Bode proposed the name Uranus, a Latinized version of the Greek deity Ouranos, the primordial god of the sky. This suggestion was eventually adopted to maintain a sense of mythological consistency in the solar system’s hierarchy. The logic was based on the mythological lineage: Saturn (Cronus) was the father of Jupiter (Zeus), so the next planet outward should logically be named after Saturn’s father, Ouranos.
Uranus is the only major planet whose name is derived directly from a figure in Greek mythology rather than a Roman one. Although the Roman equivalent for Ouranos is Caelus, the Greek name was chosen and became the international standard by the mid-19th century.
Greek Equivalents of Planetary Names
Although the official names of most planets are Roman, each has a direct Greek mythological counterpart, which satisfies the underlying interest in the Greek connection. The closest planet to the Sun, Mercury, corresponds to the Greek messenger god Hermes. Venus, the second planet, is the Roman equivalent of the Greek goddess Aphrodite.
The red planet Mars aligns with the Greek god of war, Ares. The gas giant Jupiter is the Roman name for the king of the Greek gods, Zeus. Finally, Saturn corresponds to the Greek titan Cronus, the father of Zeus.