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ORBONIX · JUPITER SYSTEM
IO
The innermost of Jupiter's four Galilean moons
and the most volcanically active world
known in the Solar System.
IO · JUPITER'S MOON
421,700 km
DISTANCE FROM JUPITER
3,643 km
DIAMETER
1.77 DAYS
ORBITAL PERIOD
1.77 DAYS
ROTATION PERIOD
5.9 g/cm³
AVERAGE DENSITY
400+ VOLCANOES
KNOWN VOLCANIC FEATURES
THE VOLCANIC MOON
Io is the innermost of Jupiter's four
large Galilean moons.
It is the most volcanically active world
known in the Solar System. Hundreds of
volcanic centers and enormous lava flows
cover its surface.
The extreme volcanic activity is caused
by tidal heating. Jupiter's enormous
gravity constantly stretches and
compresses Io while the gravitational
influence of Europa and Ganymede keeps
its orbit slightly eccentric.
This continuous flexing generates
enormous amounts of heat inside Io.
Some volcanic plumes can rise hundreds
of kilometers above the surface.
EXTREME VOLCANISM
Io has hundreds of active volcanic
centers and constantly changing
lava flows.
TIDAL HEATING
Jupiter's gravity repeatedly deforms
Io, generating heat deep inside the moon.
COLORFUL SURFACE
Sulfur and sulfur compounds create
Io's distinctive yellow, orange, red
and green surface colors.
DID YOU KNOW?
Io can produce volcanic plumes that
rise hundreds of kilometers
above its surface.
IMAGE:
NASA / JPL / UNIVERSITY OF ARIZONA /
WIKIMEDIA COMMONS