in Greek religion, god of love. In the Theogony of Hesiod (fl. 700 BC), Eros was a primeval god, son of Chaos, the original primeval emptiness of the universe; but later tradition made him the son of Aphrodite, goddess of sexual love and beauty, by either Zeus (the king of the gods), Ares (god of war and of battle), or Hermes (divine messenger of the gods). Eros was god not simply of passion but also of fertility. His brother was Anteros, the god of mutual love, who was sometimes described as his opponent. The chief associates of Eros were Pothos and Himeros (Longing and Desire). Later writers assumed the existence of a number of Erotes (like the several versions of the Roman Amor). In Alexandrian poetry he degenerated into a mischievous child. In archaic art he was represented as a beautiful winged youth but tended to be made younger and younger until, by the Hellenistic period, he was an infant. His chief cult centre was at Thespiae in Boeotia, where the Erotidia were celebrated. He also shared a sanctuary with Aphrodite on the north wall of the Acropolis at Athens. See also Cupid.

A member of a group called near-Earth (asteroid), or Earth-approaching, asteroids, Eros can pass within 22 million km (14 million miles) of Earth. During a close approach in the 1930s (before the development of direct radar ranging), astronomers were able to observe the asteroid's parallax displacement against the background stars to refine their measurement of Earth's mean distance from the Sun, the basis for the astronomical unit. Eros was the first asteroid found (1901) to display variations in brightness due to its rotation. These periodic light fluctuations were later used to determine its rotation period (5.27 hours), its elongated shape, and, with other observations, its size, which is about twice that of New York City's Manhattan Island. Spectral observations established that Eros belongs to the S compositional class, the most common class among asteroids located in the inner part of the main asteroid belt.

In 2000 the Near Earth Asteroid Rendezvous (NEAR) Shoemaker (Near Earth Asteroid Rendezvous Shoemaker) spacecraft (launched 1996) entered orbit around Eros and collected a full year of data on its surface composition, topography, mass, gravity field, internal structure, and other properties before touching down gently on its surface. NEAR Shoemaker obtained precise dimensions (33 × 13 × 13 km 【20.5 × 8 × 8 miles】), found evidence of geologic phenomena that could have originated on a much larger parent body from which Eros was derived, and obtained thousands of images revealing numerous ridges, grooves, crater chains, and boulders. A significant discovery was that Eros is an undifferentiated asteroid—i.e., it was never subjected to extensive melting and segregation into layers of distinct composition—and so may be a pristine sample of primordial solar system material.