EUROPA

also called Jupiter II, fourth largest satellite of the planet Jupiter. One of the four Galilean satellites, it was discovered by the Italian astronomer Galileo Galilei in 1610 and was named by the German astronomer Simon Marius after a figure in Greek mythology. Europa has a diameter of 3,138 km (1,946 miles), and it orbits Jupiter at a distance of approximately 670,900 km (416,900 miles). The satellite has a density of 3.03 grams per cubic cm, which indicates that it consists predominantly of rock with a fairly small component of ice or water. False-colour image of the surface of Europa, one of the satellites of Jupiter. The icy surface, Europa was observed at close range in 1979 by the U.S. Voyager 1 and 2 spacecraft and by the Galileo spacecraft in the late 1990s. Most of the satellite's surface is smooth, very bright ice. Some regions concentrated near the equator are slightly darker and have a mottled appearance. Europa's impact-crater density is much lower than that of most objects in the solar system. Europa's most striking characteristic is an intricate pattern of dark linear features that crisscross the surface. These measure several tens of kilometres wide and extend in some instances for thousands of kilometres. They seem to have little or no associated surface topography. Their origin is unknown, but their appearance suggests that they may be fractures caused by extensional stresses in Europa's crust. The smoothness of the satellite's surface indicates that its icy crust was relatively warm, soft, and mobile for at least a substantial part of its early history. in Greek mythology, the daughter either of Phoenix or of Agenor, king of Phoenicia. The beauty of Europa inspired the love of Zeus, who approached her in the form of a white bull and carried her away from Phoenicia to Crete. There she bore Zeus three sons: King Minos of Crete, King Rhadamanthus of the Cyclades Islands, and, according to some legends, Prince Sarpedon of Lycia. She later married the king of Crete, who adopted her sons, and she was worshiped under the name of Hellotis in Crete, where the festival Hellotia was held in her honour.