6/30/2023 0 Comments Io moon massThe discovery of a cloud of sodium surrounding Io led to theories that the satellite would be covered in evaporites. The plumes of Pele and Loki are visible above the limb and at the terminator, respectively.īefore the Voyager 1 encounter with Io on March 5, 1979, Io was thought to be a dead world much like the Moon. Discovery ĭiscovery image of active volcanism on Io. Spacecraft that have flown by Io since 1979 have observed numerous surface changes as a result of Io's volcanic activity. This material paints the surrounding terrain in red, black, and/or white, and provides material for Io's patchy atmosphere and Jupiter's extensive magnetosphere. Īs a result of the presence of significant quantities of sulfurous materials in Io's crust and on its surface, some eruptions propel sulfur, sulfur dioxide gas, and pyroclastic material up to 500 kilometres (310 mi) into space, producing large, umbrella-shaped volcanic plumes. In addition, eruption temperatures as high as 1,600 K (1,300 ☌ 2,400 ☏) were detected, which can be explained by the eruption of high-temperature ultramafic silicate lavas. Although most of the lava on Io is made of basalt, a few lava flows consisting of sulfur and sulfur dioxide have been seen. Lava flows on Io, tens or hundreds of kilometres long, have primarily basaltic composition, similar to lavas seen on Earth at shield volcanoes such as Kīlauea in Hawaii. Three different types of volcanic eruptions have been identified, differing in duration, intensity, lava effusion rate, and whether the eruption occurs within a volcanic pit (known as a patera). Io's volcanism has led to the formation of hundreds of volcanic centres and extensive lava formations, making it the most volcanically active body in the Solar System. Without this tidal heating, Io might have been similar to the Moon, a world of similar size and mass, geologically dead and covered with numerous impact craters. This variation in the shape of Io causes frictional heating in its interior. Io's eccentric orbit leads to a slight difference in Jupiter's gravitational pull on the satellite between its closest and farthest points on its orbit, causing a varying tidal bulge. This differs from Earth's internal heating, which is derived primarily from radioactive isotope decay and primordial heat of accretion. Io's volcanism makes the satellite one of only four known currently volcanically active worlds in the Solar System (the other three being Earth, Saturn's moon Enceladus, and Neptune's moon Triton).įirst predicted shortly before the Voyager 1 flyby, the heat source for Io's volcanism comes from tidal heating produced by its forced orbital eccentricity. Up to 400 such volcanoes are predicted to exist based on these observations. Observations of Io by passing spacecraft (the Voyagers, Galileo, Cassini, and New Horizons) and Earth-based astronomers have revealed more than 150 active volcanoes. Its volcanic activity was discovered in 1979 by Voyager 1 imaging scientist Linda Morabito. Volcanism on Io, a moon of Jupiter, is represented by the presence of volcanoes, volcanic pits and lava flows on the moon's surface. Io, with two plumes erupting from its surface
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