Io
Io is heated by tidal forces from Jupiter and has over 400 active volcanoes. Its surface is constantly renewed by lava flows — there are practically no impact craters.
astronomy.moons
Metrics
Diameter
Slightly larger than Earth's Moon.
Mass
Orbital Period
Around Jupiter, in Laplace resonance with Europa and Ganymede.
Distance to Jupiter
Relations
Io shows extreme geological activity — a comparison case for volcanic processes.
Explanations
Io is Jupiter's innermost large moon and the most volcanically active object in our solar system. Enormous tidal forces from Jupiter – pulling and squeezing Io – heat its core so much that over 400 volcanoes are active. Because of this, Io's surface is constantly being remade by lava flows, which is why you find almost no impact craters there like on other moons.
Sources
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Provenance
Status
seed
Review
none
Last Updated
2026-02-17