NEREID

in Greek religion, any of the daughters (numbering 50 or 100) of the sea god Nereus (eldest son of Pontus, a personification of the sea) and of Doris, daughter of Oceanus (the god of the water encircling the flat Earth). The Nereids were depicted as young girls, inhabiting any water, salt or fresh, and as benign toward humanity. They were popular figures in Greek literature. The best known of the Nereids were Amphitrite, consort of Poseidon (a sea and earthquake god); Thetis, wife of Peleus (king of the Myrmidons) and mother of the hero Achilles; and Galatea, a Sicilian figure loved by the Cyclops Polyphemus. one of the eight known satellites of Neptune. It was discovered photographically by the American astronomer Gerard Peter Kuiper in 1949. Nereid orbits Neptune with a period of 360.2 days; the orbit is highly elliptical and inclined to the planet's equator. The satellite's mean distance from Neptune is 5,511,000 km (3,424,400 miles). Nereid is exceedingly faint, making observations with even the largest ground-based telescopes very difficult. Thus, little is known about Nereid, but data returned by the U.S. Voyager 2 space probe in 1989 suggests that it is an asteroid-like object. Nereid has a diameter of about 340 km (210 miles).