Titan

Titan, in astronomy

Titan (tī`tən), in astronomy, the largest of the named moons, or natural satellites, of Saturn. Also known as Saturn VI (or S6), Titan is 3,200 mi (5,150 km) in diameter, orbits Saturn at a mean distance of 759,209 mi (1,221,830 km), and has equal orbital and rotational periods of 15.9454 earth days. Titan was discovered by the Dutch physicist Christiaan Huygens in 1655. Titan was thought to be the largest satellite in the solar system until recently, when it was recognized that estimates of its size had included its thick atmosphere. Titan's solid surface is slightly smaller than that of Ganymede, the largest of Jupiter's satellites. Titan is composed of about half water ice and half rocky materials. It probably consists of several layers, with a 2,100 mi (3,400 km) rocky center surrounded by several layers of different forms of crystal ice. The solid surface is surrounded by an atmosphere consisting mostly of molecular nitrogen with small amounts of methane, ethane, and other hydrocarbons. This thick, opaque atmosphere prevents the surface from being seen in visible light, although some surface detail has been observed via the Hubble Space Telescope using infrared light; one prominent feature seen in this way is c.2,500 mi (4,000 km) across, about the size of the Australian continent. Titan is the only natural satellite in the solar system with a significant atmosphere, although a much thinner one has been detected around Triton, a satellite of Neptune. Titan's atmosphere was first detected spectroscopically by the Dutch-American astronomer Gerard P. Kuiper in 1944. Titan forms a satellite pair with Hyperion; that is, the two moons interact gravitationally. In 2004 the space probe Huygens, which had been carried to Saturn by Cassini, landed on Titan and returned photographs of its surface.

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Titan, in Greek religion and mythology

Titan, in Greek religion and mythology, one of 12 primeval deities. The female Titan is also called Titaness. The Titans—six sons and six daughters—were the children of Uranus and Gaea. They were Kronos, Iapetus, Hyperion, Oceanus, Coeus, Creus, Theia, Rhea, Mnemosyne, Phoebe, Tethys, and Themis. The name Titan was sometimes applied also to their descendants, such as Prometheus, Atlas, Hecate, Selene, and Helios. The Titans, led by Kronos, deposed their father and ruled the universe. They were in turn overthrown by the Olympians, led by Zeus, in the battle called the Titanomachy. Zeus freed from Tartarus the Cyclopes and the hundred-handed giants, the Hecatoncheires, to aid him in the war. The Cyclopes forged Hades' helmet of darkness, Poseidon's trident, and Zeus' thunderbolts. With these weapons Zeus and his brothers were able to defeat the Titans. After the struggle Zeus sent Kronos to rule the Isle of the Blessed and condemned Atlas to bear the sky on his shoulders. Prometheus (and, in some myths, Oceanus and Themis), because he sided with Zeus, was allowed to remain on Olympus, but all the other Titans were condemned to Tartarus.

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Titan

In Greek mythology, any of the children of Uranus and Gaea and their descendants. There were 12 original Titans: the brothers Coeus, Crius, Cronus, Hyperion, Iapetus, and Oceanus, and the sisters Mnemosyne, Phoebe, Rhea, Tethys, Thea, and Themis. Encouraged by Gaea, the Titans rebelled against their father. Cronus deposed Uranus by castrating him, and became king himself. Cronus' son Zeus rebelled against his father, launching a struggle in which most of the Titans sided with Cronus. Zeus and his siblings finally won after 10 years, and Zeus imprisoned the Titans in a cavity below Tartarus.

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Titan

Largest moon of Saturn. Titan is the only satellite in the solar system known to have clouds and a dense atmosphere. It makes one rotation on its axis (about every 16 days) for each revolution around Saturn, thus always keeping the same hemisphere toward the planet. With a diameter of 3,200 mi (5,150 km), Titan is the second largest moon in the solar system; only Jupiter's Ganymede is larger. Its density (about 1.9 times that of water) implies that its interior is a mixture of rocky and icy materials, the latter likely being mostly water ice mixed with frozen ammonia and methane. Its atmosphere is about 95% nitrogen. Its surface, veiled in a thick brownish red haze, was largely a mystery until the arrival at Saturn in 2004 of the Cassini-Huygens spacecraft, which revealed a complex topography shaped by rains, winds, flowing liquids, and other processes similar to those acting on Earth's surface.

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Titan [′tīt·ən]

(astronomy)

The largest satellite of Saturn, with a diameter estimated to be about 3440 miles (3550 kilometers).