Jupiter

Planet Jupiter

Jupiter is the fifth planet from the Sun and the largest in the Solar System, more than twice as massive as all the other planets combined. It is named after Jupiter, the Roman name of Zeus, the king of the gods, the ruler of Olympus.

The Planet Jupiter

Jupiter was known to astronomers in ancient times because it is among the brightest objects in the night sky, after the Sun, the Moon and Venus. Pliny the Elder, writing in the first century AD, describes the orbit of Jupiter as lying lower than that of Saturn and says that the planet is carried round in twelve years (Pliny, Natural History, Book 2).

Jupiter has dozens of moons, and well over ninety are now known. The four largest were discovered by Galileo Galilei in 1610: Io, Europa, Ganymede and Callisto. Each of them is named for a figure whom Zeus (Jupiter) loved in the myths. Other moons carry names from the same circle of stories, among them Amalthea, Adrastea, Metis, Thebe, Leda, Himalia, Lysithea, Elara, Ananke, Carme, Pasiphae and Sinope.

Jupiter in Myth

The Romans identified their chief god Jupiter with the Greek Zeus. In Virgil’s Aeneid, Juno speaks of herself as the queen of the gods, and “both sister and wife” of Jupiter (Virgil, Aeneid 1.46–47), in the same relation that Hera has to Zeus in Greek myth.

The Moons and Their Stories

Io: Jupiter saw Io, the daughter of the river Inachus, returning from her father’s stream and spoke to her (Ovid, Metamorphoses 1.583–590). She was changed into a cow and, driven by Hera, wandered until she reached Egypt (Apollodorus, Library 2.1.3).
Europa: Jupiter took the shape of a bull, and Europa, the daughter of the king of Phoenicia, sat on his back; he carried her over the sea (Ovid, Metamorphoses 2.833–875).
Ganymede: Ovid says that the king of the gods burned with love for the Phrygian Ganymede and, taking the shape of a bird able to bear his thunderbolts, carried him off; Ganymede now mixes the cups and serves Jupiter his nectar (Ovid, Metamorphoses 10.155–161).
Callisto: Jupiter, going about inspecting the world, fell in love with the Arcadian maiden Callisto, and afterwards set her among the stars (Ovid, Metamorphoses 2.401–410, 2.505–507).
Amalthea: In Apollodorus, the infant Zeus was fed in a cave on Crete by nymphs, including Adrasteia, on the milk of Amalthea (Apollodorus, Library 1.1.6–7).

Jupiter in Roman Religion

In the Roman tradition, Romulus carried the arms of the enemy king he had killed to the Capitoline hill, and dedicated them to Jupiter Feretrius, marking out the site for a temple (Livy 1.10.5–7). Later, in the battle with the Sabines, he vowed a temple to Jupiter Stator, “the Stayer” (Livy 1.12.6). The great temple of Jupiter on the Tarpeian Mount (the Capitol) was vowed by Tarquinius Priscus, who levelled the site for it (Livy 1.38.7), and was built by the later king Tarquinius Superbus (Livy 1.55.1).