Io
The most volcanic world in the solar system
Io is squeezed and stretched by Jupiter's immense gravity, generating enough internal heat to power 400+ active volcanoes. Its surface is a sulfurous yellow-orange canvas constantly being repaved by lava.
Image: NASA / Galileo
Vital statistics
Orbits
Jupiter
Diameter
3,643 km
Gravity vs Earth
0.183 g
Surface Temp
-130 °C avg / 1,600 °C lava
Orbital period
1.77 Earth days
Did you know
Volcanic plumes rise 500 km above the surface.
Fact 01
Tidal flexing of Io produces 100× more heat than Earth's interior.
Fact 02
Has almost no impact craters — its surface is constantly resurfaced.
Fact 03
Deep dive
Composition
Silicate rock with an iron-sulfide core and crust coated in sulfur and SO₂ frost.
Discovery
Discovered by Galileo Galilei in 1610 — one of the four Galilean moons.
Notable missions
- • Voyager 1/2
- • Galileo
- • Juno (recent close flybys)
Research & publications
Jump straight into peer-reviewed papers, preprints and authoritative references for Io.
arXiv (preprints)
Open-access preprints in physics & astrophysics.
NASA ADS
The definitive bibliographic database for astronomy.
Google Scholar
Cross-publisher academic search.
Nature
Peer-reviewed articles in Nature & sister journals.
Wikipedia
Encyclopedic overview & onward references.
Tip: ask the Research AI for a curated reading list → /research
