Reference image
Object guide
Io is the most volcanically active body in the Solar System, driven by tidal heating from Jupiter and orbital interactions with other Galilean moons. Its surface is dotted with active plumes and colorful sulfur compounds. Io is approximately 3,643.2 km across.
How to observe Io
Io is resolved as a separate world mainly through imaging or spacecraft data; visually, its relationship to jupiter is the key observing context.
Scientific context
Useful scale comparisons are 0.286 Earth diameters, 0.183 g surface gravity, 0.005 Earth years per orbit. These values are rounded from the catalogue measurements shown on this page.
- Radius
- 1,821.6 km
- Diameter
- 3,643.2 km
- Mass
- 8.93E+22 kg
- Mean density
- 3.527 g/cm³
- Surface gravity
- 1.796 m/s² (0.183 g)
- Orbital period
- 1.769 days (0.005 years)
- Parent body
- jupiter
0.286 Earth diameters0.183 g surface gravity0.005 Earth years per orbit
Source: NASA Science (checked 2026-08-09). Values are rounded catalogue measurements.
Interactive orbit model
Aug 13, 2026, 22:251×
Calculated positions / separate exploration scales