Mimas:
Reassembed Moon of Saturn
- Innermost of Saturn's large moons.
- An icy 390-km (241-mile) globe.
- Very faint in Saturn's glare when viewed from Earth.
- Discovered as early as 1789 by Sir William Herschel.
- Density is low, indicating that it is mostly comprised of ice.
- Heavily cratered (like Rhea, Dione & Tethys).
- It lacks resurfaced plains like those found on Encladus.
- This indicates low geologic activity.
- Mimas lacks size to generate high internal temperatures and dramatic volcanism.
- One feature is unique:
- A single grater about a third of the diameter of Mimas.
- This crater is named for Hershel.
- Appearance seems to be fresh, unmarred by other impacts.
- It is about 130 km (80 miles) across.
- It extends to a depth of 9 km (5.6 miles).
- A broad central peak rises about 4 km (13,000') high.
- It's form is similar to that of two familiar lunar craters -
- This would make it about the size of the Yellowstone National Park.
- Severe damage to Mimas is likely to have occurred during its impact.
- Mimas receives about 12 times as many impacts as Saturn's outermost moon.
- It is highly likely that Mimas may have been blown apart and reassembled.
- This may also explain the debris that comprises Saturn's rings.
- The revolution period (orbit) of Mimas is 22.6 hours.
- Particles in the central portion of the rings orbit Saturn in twice this amount of time.
- Gravity from Mimas' mass and density draws particles outward from Saturn.
- A gap is thus formed in the region the debris is drawn from.
- This is referred to Cassini's Division.
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