Dione


Dione
/duy oh"nee/, n.
1. Class. Myth. a Titan and a consort of Zeus.
2. Astron. a moon of the planet Saturn.

* * *

 in Greek mythology, a consort and, at Dodona in Epirus, a cult partner of Zeus, the king of the gods. Since the partner and wife of Zeus was normally the goddess Hera, it has been conjectured that Dione is an older figure than Hera. Dione was variously described. In the Iliad she is mentioned as the mother of the goddess Aphrodite by Zeus; in Hesiod's Theogony, however, she is simply identified as a daughter of Oceanus. Other writers have identified her as the mother of Dionysus.

 fourth nearest of the major regular moons of Saturn. It was discovered by the Italian-born French astronomer Gian Domenico Cassini (Cassini, Gian Domenico) in 1684 and named for a daughter of the Titan Oceanus in Greek mythology.

      Dione has a diameter of 1,120 km (696 miles) and revolves around Saturn in a prograde, nearly circular orbit at a mean distance of 377,400 km (234,500 miles), which is within the outer part of Saturn's tenuous E ring. It is accompanied in its orbit by two much smaller moons, Helene and Polydeuces (also named for Greek mythological figures). Helene, which has a diameter of about 30 km (20 miles), maintains a gravitationally stable position 60° ahead of Dione. Polydeuces has less than half the diameter of Helene and follows Dione by 60°, though with large deviations from its mean position. The orbits of these tiny companion moons can be compared to those of Jupiter's Trojan asteroids (asteroid).

      Tidal interactions with Saturn have slowed Dione's rotation so that it now turns synchronously with its orbital motion, always keeping the same hemisphere toward the planet and always leading with the same hemisphere in orbit. The surface of Dione shows great brightness contrasts, with the trailing hemisphere generally darker than the leading one. On average, however, Dione is highly reflective, which indicates a surface composed of large amounts of geologically fresh water ice. The moon's low density, which is 1.5 times that of water, is consistent with a bulk composition of about equal amounts of ice and rock. Dione is heavily covered in places with impact craters; their density and distribution of sizes suggest a geological age close to four billion years. In other areas, however, the crater density is lower, which suggests that the moon may have experienced substantial ice melting and resurfacing. It is also possible that Dione's surface is continually coated by new ice particles deposited from the E ring.

      Most of Dione's craters are found on the bright, leading hemisphere. The opposite hemisphere is broken by many bright linear features that form a polygonal network. Some of these bright features are associated with linear troughs and ridges and may have been caused by episodic tectonic activity. Wispy features seen in Voyager spacecraft images had been thought to be deposits of recondensed volatile material that erupted from Dione's interior along linear fractures. Higher-resolution images from the Cassini spacecraft, however, show no evidence of such activity. The asymmetry of the moon's surface is not understood, although there is evidence of a major impact near the centre of the linear network on the trailing hemisphere.

      Like many objects in orbit around Saturn, Dione is involved in an orbital resonance; i.e., its 66-hour trip around Saturn is twice that of the nearer moon Enceladus. This relationship has been proposed as a source of the dramatic tidal heating seen in Enceladus, but the details of this mechanism have not been worked out.

William B. Hubbard
 

* * *


Universalium. 2010.

Look at other dictionaries:

  • Dione — ist: in der griechischen Mythologie: Dione (Mythologie), eine Titanin, Gattin des Zeus von Dodona Dione (Tochter des Atlas), Gattin des Tantalos in der Astronomie: Dione (Mond), ein Saturnmond (106) Dione, ein Asteroiden Familienname folgender… …   Deutsch Wikipedia

  • Dione — Dioné Cette page d’homonymie répertorie les différents sujets et articles partageant un même nom …   Wikipédia en Français

  • Dione — Saltar a navegación, búsqueda Dione puede ser: En la mitología griega, Dione es la madre de Afrodita. En astronomía, Dione es un satélite de Saturno. También en astronomía, (106) Dione es un asteroide. Obtenido de Dione Categoría:… …   Wikipedia Español

  • dione — ● dione nom féminin Synonyme de dicétone. ● dione (synonymes) nom féminin Synonymes : dicétone …   Encyclopédie Universelle

  • Dione — [dī ō′nē] n. a satellite of Saturn, sharing an orbit with a smaller satellite (Dione B) …   English World dictionary

  • Diōne [1] — Diōne, 1) Okeanide, galt in Dodona als Gemahlin des Zeus (an der Stelle der Here) u. wurde von diesem Mutter der Aphrodite. 2) (Dionäa), so v.w. Aphrodite, als Tochter der D. 3) D., Tochter des Atlas, von Tantalos Mutter des Pelops u. der Niobe …   Pierer's Universal-Lexikon

  • Diōne [2] — Diōne (Cytherea D.), Venusmuschel aus der Unterfamilie der Herzmuscheln …   Pierer's Universal-Lexikon

  • Diōne — Diōne, Trabant des Saturn, s.d. 2) …   Pierer's Universal-Lexikon

  • Diōne — Diōne, im griech. Mythus Tochter von Okeanos und Tethys oder Uranos und Gäa, von Zeus Mutter der Aphrodite, die daher Dionaia, sogar auch selbst D. heißt. Sie ward zu Dodona (s. d.) als Gattin des Zeus verehrt. Als aber das Orakel zu Dodona seine …   Meyers Großes Konversations-Lexikon

  • Dione — Diōne, Tochter des Uranus und der Gäa, sprachlich und inhaltlich die weibliche Ergänzung des Zeus, ward noch später als Gemahlin des Zeus verehrt …   Kleines Konversations-Lexikon

  • Dióne — DIÓNE, es, (⇒ Tab. I.) des Aether und der Erde Tochter. Hygin. Præf. p. 2. Sie zeugete hernach mit dem Jupiter die Venus. Id. ibid. p. 9. Apollod. L. I. c. 3. §. 1. Sie wird sonst auch gar oft für die Venus selbst genommen. Stat. lib. I. Silvar.… …   Gründliches mythologisches Lexikon


Share the article and excerpts

Direct link
Do a right-click on the link above
and select “Copy Link”

We are using cookies for the best presentation of our site. Continuing to use this site, you agree with this.