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Callisto’s icysurface is covered by impact cratersOceanus Procellarum (Ocean of Storms) is a vast lava-covered plainTitan’s hazy orange
atmosphere conceals adeep-frozen surfacewith shifting icy
continents and lakesof liquid methaneThe Solar System has more than 190 moons orbiting six of the planets – only Mercury and Venus are moonless. They range in size from Ganymede, a satellite of Jupiter, which
MOONSis larger than Mercury, to S/2009 S1, a 300-metre moonlet orbiting within Saturn’s rings. All are made of rock, or rock and ice, and many have surfaces littered with impact craters, formed when the moons were bombarded by asteroids in the past. Nineteen Solar-System moons are more than 400 km (250 miles) wide. These large moons are round but the more numerous smaller moons are irregular in shape.Uneven surface
may be a result of
the moon shatteringthen reassembling Long faults with icy floors formed when Ariel’s crust expandedDark spots are major active volcanic centres – more than 80 have been identifiedtiT
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