Surface of Io



This is an image of the surface of Io,
looking down on a volcano and the lava plain surrounding it.
Click on image for full size version (344K GIF)
Image from: NASA
The surface of Io is completely volcanic, with lava flows of sulfur from the interior, as shown in this image. White patches in the image indicate areas of surface SO2 frost.

The heat for this volcanism stems from tidal forces due to the unique position of Io relative to Jupiter and the other moons. Io is a small moon, very close to Jupiter, and well inside the other 3 main moons. Io feels the gravitational pull first of Jupiter, then of the outside moons when they sweep by. The alternating pull of gravity has a push-me, pull-me effect on Io, which deforms the moon, and warms it just the way a coat hanger warms when you bend it first one way, then the other way.

Due to this warming, the surface of Io has many volcanoes,.

Return to moons


Surface of Io



This is an image of the surface of Io,
looking down on a volcano and the lava plain surrounding it.
Click on image for full size version (344K GIF)
Image from: NASA
The surface of Io is completely volcanic, with lava flows of sulfur from the interior, as shown in this image. White patches in the image are areas of frost made of sulfur dioxide instead of water.

The heat for this volcanism comes from the special position of Io relative to Jupiter and the other moons. Io is a small moon, very close to Jupiter, and well inside the other 3 main moons. Io feels the gravitational pull first of Jupiter, then of the outside moons when they sweep by. The alternating pull of gravity has a push-me, pull-me effect on Io, which deforms the moon, and warms it just the way a coat hanger warms when you bend it first one way, then the other way.

Due to this warming, Io has many volcanoes.

Return to moons


Surface of Io



This is an image of the surface of Io,
looking down on a volcano and the lava plain surrounding it.
Click on image for full size version (344K GIF)
Image from: NASA
Unlike the other moons of Jupiter, Io is not made of ice. In fact, the surface of Io is rocky with many volcanoes. The volcanoes pour out lava of sulfur from the inside of Io.

The surface of Io can be cold enough for frost, however. White patches in the image indicate areas of frost on the surface.

The biggest volcanos of Io are called Loki and Prometheus. Between the volcanos are lava plains, much like those found in Hawaii near a volcano.

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Last modified April 28, 1997 by the Windows Team

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