Astronomy Picture of the Day

Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.

December 20, 1999
See Explanation. Clicking on the picture will download the highest resolution version available.

Lava Fountain on Jupiter's Io
Credit: Galileo Project, SSI, University of Arizona, JPL, NASA

Explanation: A lava fountain shooting over a kilometre high has been discovered on Jupiter's moon Io. The robot Galileo spacecraft orbiting Jupiter photographed the volcanic eruption during its close flyby of the moon late last month. The fountain is visible in the above mosaic of images from the flyby. The lava plume was so bright it saturated Galileo's camera, and so has been digitally reconstructed in false colour. The hot lava appears to be shooting from a 20-kilometre long canyon on Io's active surface.

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Authors & editors: Robert Nemiroff (MTU) & Jerry Bonnell (USRA)
NASA Technical Rep.: Jay Norris. Specific rights apply.
A service of: LHEA at NASA/ GSFC
& Michigan Tech. U.