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APOD
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.
Io in True Color
Explanation: The strangest moon in the Solar System is bright yellow. This picture , showing Io's true colors, was taken in 1999 July by the Galileo spacecraft currently orbiting Jupiter. Io's colors derive from sulfur and molten silicate rock . The unusual surface of Io is kept very young by its system of active volcanoes . The intense tidal gravity of Jupiter stretches Io and damps wobbles caused by Jupiter's other Galilean moons . The resulting friction greatly heats Io 's interior, causing molten rock to explode through the surface. Io's volcanoes are so active that they are effectively turning the whole moon inside out. Some of Io 's volcanic lava is so hot it glows in the dark .
| Date | July 15, 2001 |
|---|---|
| Credit | Credit: Galileo Project , JPL , NASA |
| Authors & editors: | Robert Nemiroff (MTU) & Jerry Bonnell (UMCP) |
| A service of: |
ASD at NASA / GSFC, NASA Science Activation & Michigan Tech. U. |