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.

July 6, 1998
See Explanation.  Clicking on the picture will download 
 the highest resolution version available.

Sizzling Io
Credit: Galileo Project, JPL, NASA

Explanation: What's cooking on Io? This active moon of Jupiter is marked with volcanoes spewing lava that is now known to be hotter than any lava on Earth. Above is the highest resolution color-enhanced image yet composed of the most active surface in our Solar System. Features as small as three kilometers are visible. Sulfur compounds cause many of Io's unusual colors, while darker regions are probably composed of silicate rock.

Tomorrow's picture: M8: The Lagoon Nebula

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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.