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Io
Learn about Io, Jupiter's moon with the most active volcanoes in the solar system
global mosaic of Jupiter's moon Io Io's Tvashtar volcano volcanic plumes on Io Io, in Jupiter's shadow, photographed by the Galileo spacecraft on May 6, 1997. The relative brightnesses of Io's features are enhanced with added colour, red being the most intense, yellow-green moderate, and blue the faintest. Small red and yellow-green spots are probably lava flows or lakes, while the bright area extending from Io's left limb corresponds to the plume from the volcano Prometheus. The diffuse glow on the right limb also has plumelike characteristics. Jupiter's four Galilean moons Io, moon of Jupiter. A massive volcano can be seen on the horizon. Jupiter and Io Jupiter's atmospheric blemishes
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Io: References & Edit History

Article Contributors

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  • The Editors of Encyclopaedia Britannica
    Encyclopaedia Britannica's editors oversee subject areas in which they have extensive knowledge, whether from years of experience gained by working on that content or via study for an advanced degree. They write new content and verify and edit content received from contributors.

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Article History

Type Description Contributor Date
Modified link of Web site: IOPscience - The Planetary Science Journal - Io’s Optical Aurorae in Jupiter’s Shadow. Oct 29, 2026
Add new Web site: Frontiers - Frontiers in Astronomy and Space Sciences - The temporal variability of Io’s hotspots. Jan 29, 2026
Add new Web site: IOPscience - The Planetary Science Journal - Io’s Optical Aurorae in Jupiter’s Shadow. Aug 13, 2025
Add new Web site: University of Colorado Boulder - LASP - The Interior of Io (PDF). Jan 30, 2025
Add new Web site: The University of Arizona - Lunar and Planetary Laboratory - Io: A unique world in our Solar System (PDF). Nov 12, 2024
Links added. Jul 19, 2023
Add new Web site: The Planets - Io Facts. Jul 11, 2023
Add new Web site: The Nine Planets - Io. May 06, 2023
Add new Web site: The Planetary Society - Io, Jupiter�s chaotic volcano moon. Mar 21, 2023
Add new Web site: Space - Io: A guide to Jupiter's volcanic moon. Sep 14, 2022
Updated values of Io's diameter and density. May 03, 2021
Add new Web site: HyperPhysics - Io. Sep 06, 2016
Media added. Apr 13, 2016
Added image of plume from Io's Tvashtar volcano. Dec 10, 2009
Added image of plume from Io's Tvashtar volcano. Dec 10, 2009
Media revised. Mar 26, 2008
Added new Web site: University of Tennessee - Astronomy 161: The Solar System. Jun 30, 2006
Added new Web site: The Nine Planets - Phobos. Jun 08, 2006
Added new Web site: Views of the Solar System - Io. May 12, 2006
Article revised. Jun 16, 2005
Article added to new online database. Jul 20, 1998
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