Enceladus

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Enceladus is one of the innermost moons of Saturn. It is quite similar in size to Mimas, but has a smoother, brighter surface. Enceladus reflects almost 100 percent of the sunlight that strikes it. Unlike Mimas, Enceladus displays at least five different types of terrain. Parts of Enceladus shows craters no larger than 35 km in diameter. Other areas show regions with no craters, indicating major resurfacing events in the geologically recent past. There are fissures, plains, corrugated terrain and other crustal deformations. All of this indicates that the interior of the moon may be liquid today, even though it should have frozen aeons ago. It is postulated that Enceladus is heated by a tidal mechanism similar to Jupiter's moon Io. Enceladus is perturbed in its orbit by Saturn's gravitational field and by the large neighboring satellites Tethys and Dione.

A Bright, Icy Moon

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Enceladus has the highest albedo of any known object in the Solar System. It reflects almost 100% of the sunlight it receives. This high reflectivity is caused by a very smooth surface of fresh water ice. Since Enceladus reflects so much of the sunlight it receives, its surface temperature is a chilling -330° F (-201° C).

Features of Enceladus

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Unlike many of Saturn's other ice moons, Enceladus contains at least five types of surface features. In addition to cratered areas, this moon contains smooth plains, linear cracks and ridges, fissures, and unusual crustal deformations. The craters on Enceladus are all smaller than 21 miles (35 km) in diameter. The cracks, ridges, and other unusual features seem to indicate that the interior of the moon may still be liquid. This could be caused by internal heat as a result of tidal forces from Saturn, very similar to those on Jupiter's moon Io. Enceladus is perturbed in its orbit by the gravitational fields of Saturn and its neighboring moon, Tethys and Dione. The smooth plains indicate a very young surface, perhaps only a few hundred million years old. These areas were almost certainly formed by water flowing to the surface from deep inside the moon. This could even be the result water volcanoes. Some astronomers believe that Enceladus may still be active. It may still be in the process of resurfacing itself. Enceladus has no detectable atmosphere and no magnetic field.

Statistics for Enceladus

Discovered by                            -    William Herschel
Year of Discovery                       -    1789
Diameter                                  -    313.2 miles (504 km)
Mean Distance from Saturn          -    147,948 miles (238,020 km)
Rotational Period                       -    1.37 Days
Orbital Period                            -    1.37 Days
Orbital Eccentricity                     -    0.0045
Orbital Inclination                       -    0.02 degrees
Mean Surface Temperature          -    -330 F (-201 C)
Main Atmospheric Component       -    None
Apparent Magnitude                    -    11.7