Page 23 - Curriculum Visions Dynamic Book

/Io
galileo A U.S. space probe launched in October 1989 and designed for intensive investigation of Jupiter.
gravitational pull The force of attraction between bodies. The larger an object, the more its gravitational pull on other objects.
lava Hot, melted rock from a volcano. limb The outer edge of a celestial body,
including an atmosphere if it has one.
vent A tube or fissure that allows volcanic materials to reach the surface of a planet.
volcano A mound or mountain that is formed from ash or lava.
 These images show how rapidly the surface of Io changes. The pictures were taken 5 months apart by the Galileo spacecraft. A new dark spot 400 kilometres in diametre, which is roughly the size of Arizona, surrounds a volcanic centre named Pillan Patera (right of centre). The eruption is 120 kilometres high.
 This is what Io looks like using Earth-bound telescopes. The bulge on the upper right
is a volcano erupting.
 This is a picture of Culann Patera, one of the most colourful volcanic centres on Io, as seen by the Galileo spacecraft. Culann’s central caldera (above and to the right of centre) has a highly irregular, scalloped edge and a green-coloured floor. Lava flows spill out of the caldera on all sides. The loose red material around the caldera is believed to be a compound of sulfur deposited from a plume of gas.
The greenish material may be a coating of sulfur-rich material on warm lava.
23