Page 26 - Curriculum Visions Dynamic Book

 The internal structure of Io. A thin crust covers a molten sulfurous mantle and an iron core.
Io spins on its axis once every 1.8 Earth days, which is the same as the length of time it takes to go around Jupiter. As a result, it always keeps the same face to Jupiter (called synchronous rotation).
Io has a nearly circular orbit, about 422,000 km from the centre of Jupiter. The density of Io is
3.5 g/cm3, which suggests it is a rocky rather than a
gaseous body.
It has a thin, transparent atmosphere made
mainly of sulfur dioxide. It is believed that the source of the lava is a molten mantle below the
crust, and below it is a core of molten iron and iron sulfide some 1,800 km in diametre.
Io’s volcanic plumes generate particles that are pulled into Jupiter’s magnetic field,
creating a tube of ionized particles.
atmosphere The envelope of gases that surrounds the Earth and other bodies in the universe.
axis (pl. axes) The line around which a body spins.
core The central region of a body. crust The solid outer surface of a
rocky body.
density A measure of the amount of matter in a space.
ionized Matter that has been converted into small charged particles called ions.
magnetic field The region of influence of a magnetic body.
mantle The region of a planet between the core and the crust.
molten Liquid, suggesting that it has changed from a solid.
orbit The path followed by one object as it tracks around another.
synchronous rotation When two bodies make a complete rotation on their axes in the same time.
For more on Voyager see “Outer worlds” in Volume 6: Journey into space.
oager
 Voyager is the space probe that captured the first spectacular images of Io, Europa, Ganymede, and other parts of the Jovian system.
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