See also: Io
Io (J I Io) is a Natural satellite of Jupiter. It is one of the four the moons galiléennes of Jupiter, nearest to planet. Observed for the first time the January 7th 1610 by Galileo, it was named thus by Simon Marius according to Io, conquest in love with Zeus persecuted by the wife of this last, Héra - of which it had been priestess.
DescriptionIo is especially remarkable for its Volcan active ism (characteristic remarkable which differently was observed only on the Ground, Triton and Encelade); it is the most active object of the Solar system.
With the difference of the terrestrial volcanos, the volcanos on Io reject compounds of the Soufre, of which perhaps of the Sulfur dioxide.
The energy necessary to this activity probably comes from the interactions of tide between Io, Europe, Ganymède and Jupiter. The three moons are in orbital Résonance in a 4:2 report/ratio: 1. Although Io always presents the same one vis-a-vis Jupiter, the presence of Europe and Ganymède makes it waver a little. This interaction deforms the surface of Io which is raised and drops up to 100 Mètre S and product of the Chaleur by internal friction.
The orbit of Io also crosses the lines of the Magnetic field of Jupiter, which generates a Electric current. Although it is not a great energy source not compared with the heating due to the forces of tide, this current dissipates a power of more than 1 will téra Watt with a potential of 400 000 Volt S. This electric current involves with far from the Atome S Ion ized coming from Io ata rate of thousand kilograms a second. These ionized particles form a Tore which radiates intensely in the Ultraviolet around Jupiter. The particles which escape from this torus are partially responsible for the exceptionally wide Magnétosphère of Jupiter. Recent data coming from the Sonde Galileo indicate that Io could have its own magnetic field.
The site of Io with respect to the Ground and of Jupiter has a strong influence on the intensity of the emissions of waves radio joviennes collected on Earth. Jupiter is indeed an intense and irregular source of radio waves in the field of 500 Khz with 40 MHz, and these radio transmissions seem controlled by its Io satellite.
VolcanicityOne as certain plumes of the volcanic eruptions of Io go up to more 300 kilometers above surface before falling down, the matter being ejected surface at a speed of approximately 1000 m/s. These volcanic eruptions are very changeantes; during the four months separating the arrival from the probes To travel 1 and 2, some of them stopped and others started. The deposits surrounding the volcanos change also aspect.
With the difference of the majority of the moons of the external Solar system, the composition of Io is vaguely similar to that of the telluric planets, which are mainly made up of magma rich in Silicate S. Recent data coming from the Galileo probe indicate that Io has a core of a ray of at least 900 kilometers made up of Iron, perhaps mixed with Sulfide of iron.
The surface of Io is almost completely deprived of crater S, which means that it must be very recent. In addition to the volcanos, one finds on the surface of Io of the not-volcanic mountains, of many lakes of molten Soufre, of the deep Caldeira S of plusieurs kilometers and of extended from flows of basic fluids Viscosity of hundreds de kilometers length, probably composed of the certain shape of molten sulfur or silicates. Sulfur and its compounds have a range of colors (especially yellow, red and black) which are responsible for the varied aspect of Io.
The analysis of the images To travel carried out the scientists to believe that the flows of lava on the surface of Io are most of the time made up of various molten sulfur compounds. However, of the studies Infrarouge S undertaken later on starting from the ground indicate that they are too hot to be liquid sulfur. Some of the hottest spots on Io can reach temperatures as high as 2000 K, although the average is definitely lower, approximately 130 K. A current idea is that the lava of Io is made up of rocks in fusion rich in silicates. Recent observations of the Space telescope Hubble indicate that this matter east can be rich in Sodium.
AtmosphereIo has thin a atmosphere made up of Sulfur dioxide and perhaps of some other gases. With the difference in the others satellite galiléens, Io has only little or not water. It is probably because at the beginning of the evolution of the solar system, Jupiter was enough hot to drive out the volatile elements near Io but not enough hot to make in the same way with its other moons.
ToponymyThe names of the remarkable formations on the surface of Io are relating to the names of the divinities of fire in various mythologies.
Let us quote in particular: Shovel (Hawaii), Prométhée and Héphaïstos (ancient Greece), Loki (Scandinavian misadventure of Prométhée), Marduk (Babylon), Maui (Polynesia), Creidne (god of metal Irish), Culann (Irish chief of the blacksmiths), Inti (launcher of the lightning INCA), Surt (German chief of the giants of fire).
One also finds references to the solar gods: Amaterasu (Japan), Ulgen (Siberia) and Viracocha (INCA), amirani, Masubi.
Lastly, the history of Io, become main of Jupiter, is evoked by names relative to its stay in Egypt: Horus, Râ, Apis and Inachus.
- the Asteroid 85 Io
- Astrofiles : IO
Simple: Io (moon) Zh-classical: 木衛一
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