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ORBONIX · SATURN SYSTEM
DIONE
A bright icy moon of Saturn covered with
craters, cliffs and enormous fractures.
DIONE · NASA / CASSINI
1,123 km
DIAMETER
377,400 km
DISTANCE FROM SATURN
2.74 DAYS
ORBITAL PERIOD
1.48 g/cm³
AVERAGE DENSITY
ICE + ROCK
MAIN COMPOSITION
0.02°
ORBITAL INCLINATION
THE ICY MOON
Dione is one of Saturn's major icy moons.
Its surface is dominated by water ice and
is covered with impact craters.
One of its most recognizable features is
a network of bright fractures called
wispy terrain. These huge cliffs and
fractures can stretch for hundreds of
kilometers across the surface.
Dione is also tidally locked to Saturn,
meaning that the same hemisphere always
faces the planet.
Scientists have also found evidence that
Dione may contain a subsurface ocean beneath
its icy crust.
WISPY TERRAIN
Long bright cliffs and fractures cross
parts of Dione's surface.
ICY SURFACE
Dione is composed primarily of water ice
mixed with a significant rocky component.
POSSIBLE OCEAN
Measurements suggest that a liquid-water
ocean may exist beneath the surface.
DID YOU KNOW?
Dione's bright fractures can stretch for
hundreds of kilometers
across its icy surface.
TECTONICS ON AN ICY MOON
Dione combines heavily cratered terrain with long bright fractures and cliffs produced by tectonic deformation of its icy crust. These structures show that the moon experienced internal geological activity after much of its older cratered surface had formed.
Measurements of Dione and other mid-sized Saturnian moons help scientists compare how internal heat, ice and orbital evolution produce different geological histories.
IMAGE:
NASA / JPL-CALTECH / SPACE SCIENCE INSTITUTE /
CASSINI