Page 33 - Curriculum Visions Dynamic Book

/ Ganmede / Callisto
Callisto
Of its largest moons, Callisto is the furthest from Jupiter. The moon is 4,800 km across and orbits about 1.8 million km from Jupiter.
Compared with Io and Europa, the surface of Callisto appears dark. Also, unlike the inner moons, Callisto’s surface is heavily marked with impact craters, somewhat like Earth’s Moon. This suggests that Callisto is geologically inactive and has been so since the early stages of the development of the solar system.
aurora A region of illumination, often in the form of a wavy curtain, high in the atmosphere of a planet.
convection currents The circulating flow in a fluid (liquid or gas) that occurs when it is heated from below.
crater A deep bowl-shaped depression in the surface of a body formed by the high-speed impact of another, smaller body.
magnetic field The region of influence of a magnetic body.
magnetism An invisible force that has the property of attracting iron and similar metals.
magnetosphere A region in the upper atmosphere, or around a planet, where magnetic phenomena such as auroras are found.
 Callisto has been subject to a long history of impacts, as shown by the
white scars on an otherwise
dark surface. Callisto’s
surface is uniformly cratered but is not uniform in colour or
brightness. It is thought that the brighter areas are
mainly ice, and the darker areas are highly eroded, ice-
poor material; but it is not clear what has caused the erosion.
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