archive / atlas record
Io
The most volcanically active world known.
- classification
- Volcanic moon
- system
- Jupiter system
Io is heated by strong tidal forces from Jupiter and neighbouring moons, powering widespread volcanic activity.
- Class
- Volcanic moon
- Location / system
- Jupiter system
- Distance
- 421,700 km mean distance from Jupiter
Only values with an established scientific consensus are listed. Where a quantity is uncertain or model-dependent, it is discussed in the sections below rather than stated as data.
Overview (starter entry, expanded review pending)
Io is heated by strong tidal forces from Jupiter and neighbouring moons, powering widespread volcanic activity.
Imaging, spectra and orbital dynamics
Io's surface or atmosphere is constrained by telescopic and spacecraft imaging where available; spectra identify materials, while repeated position measurements establish its orbit and system context.
- What remains least constrained about Io?Composition, internal structure, formation history or local environment can require different observations and may remain model-dependent.
Items above are unresolved. Hypotheses are labelled as such and are not presented as confirmed findings.
NASA // verified 28 September 2026
NASA/JPL // verified 28 September 2026