Neptune (redirected from Neptune's weather)

Neptune, in Roman religion and mythology

Neptune, in Roman religion and mythology, god of water. He was presumably an indigenous god of fertility, but in later times he was identified with the Greek Poseidon, god of the sea. At his festival, the Neptunalia (July 23), arbors were dedicated to him.

---

Neptune, in astronomy

Neptune, in astronomy, 8th planet from the sun at a mean distance of about 2.8 billion mi (4.5 billion km) with an orbit lying between those of Uranus and the dwarf planet Pluto; its period of revolution is about 165 years. (Pluto has such a highly elliptical orbit that from 1979 to 1999 it was closer to the sun than Neptune; it will remain farther from the sun for 220 years, when it will again pass inside Neptune's orbit.) Neptune was discovered as the result of observed irregularities in the motion of Uranus and was the first planet to be discovered on the basis of theoretical calculations. J. C. Adams of Britain and U. J. Leverrier of France independently predicted the position of Neptune, and it was discovered by J. C. Galle in 1846, the day after he received Leverrier's prediction. Neptune has an equatorial diameter of about 30,700 mi (49,400 km), nearly four times that of the earth, and a mass about 17 times the earth's mass. It is much like Uranus and the other giant planets, with a thick atmosphere of hydrogen, helium, methane, and ammonia, a relatively low density, and a rapid period of rotation. On Aug. 24–25, 1989, the U.S. spacecraft Voyager 2 observed Neptune and its moons. It discovered that Neptune's atmosphere has zones like Jupiter's as well as giant storm systems as dark spots on its surface. Although Neptune receives a much smaller fraction of the sun's radiation than does Uranus, its surface temperature is similar: −350°F; (−212°C;).This may indicate a possible internal heat source. Neptune's largest moon, Triton, was discovered in 1846, a month after the discovery of the planet itself. Triton has a diameter of about 1,700 mi (2,700 km), and its motion is retrograde (see retrograde motion), i.e., opposite to that of the planet's rotation. Its surface temperature is −400°F; (−240°C;), making it one of the coldest objects in the solar system. Nereid, discovered in 1949, has a diameter of about 210 mi (338 km), is very faint, and has a highly elliptic orbit; it may be of asteroid origin. Voyager discovered six smaller dark moons orbiting between the planet and Triton: Naiad, Thalassa, Despina, Galatea, Larissa, and Proteus—all irregularly shaped, ranging from 35 to 260 mi (58–418 km) in diameter. Since Neptune was named for the Roman god of the sea, its moons were named for various lesser sea gods and nymphs in Greek mythology. Five additional moons, as yet unnamed, were discovered using earth-based telescopes in 2002 and 2003. Voyager also found a faint ring system with three bands. These are named Adams, Leverrier, and Galle in honor of the planet's discoverers. Composed of small rocks and dust, the rings are not uniform in thickness or density. Adams, the outermost, contains three prominent arcs named Liberty, Equality, and Fraternity.

Bibliography

See P. Moore, Planet Neptune (1989); E. Burgess, Far Encounter: The Neptune System (1992); G. E. Hunt et al., Atlas of Neptune (1994).

---

Neptune

Eighth planet from the Sun, discovered in 1846 and named for the Roman god of the sea. It has an average distance from the Sun of 2.8 billion mi (4.5 billion km), taking nearly 164 years to complete one orbit and rotating every 16.11 hours. Neptune has more than 17 times Earth's mass, 58 times its volume, and 12% stronger gravity at the top of its atmosphere. It has an equatorial diameter of 30,775 mi (49,528 km). Neptune consists largely of hydrogen and helium. It has no solid surface; its interior is believed to consist of a fluid mixture of rock, ices, and gas. Its atmosphere contains substantial amounts of methane gas, whose absorption of red light causes Neptune's deep blue-green colour. The Voyager 2 space probe in 1989 discovered winds of over 1,570 mi/hour (700 m/second), the fastest known for any of the Sun's planets, and dark spots that appear to be storms similar to Jupiter's Great Red Spot. Neptune receives little solar radiation, but it radiates substantially more energy than it receives, which indicates an internal heat source. Neptune's weak magnetic field traps charged particles in a belt around the planet. Neptune has a system of rings, made up largely of dust-size particles, and at least 13 moons; the largest is Triton, almost as big as Earth's Moon.

---

Neptune

Neptune holding his trident, classical sculpture; in the Lateran Museum, Rome

(credit: Alinari/Art Resource, New York)

In Roman religion, the god of water. Neptune was originally the god of fresh water, but by 399 BC he was identified with the Greek god Poseidon and thus became a deity of the sea. His female counterpart, Salacia, probably began as a goddess of spring water but was later equated with the Greek goddess Amphitrite. Neptune's festival (Neptunalia) took place in the heat of summer (July 23), when fresh water was scarcest. In art Neptune is often given Poseidon's attributes, the trident and dolphin.

---

Neptune

in allegories of the elements, personification of water. [Art: Hall, 128]

See : Water

---

Neptune - A hypertext system for computer assisted software engineering, developed at Tektronix.