Star date: 10:18:98
Saturns Smaller Moons
Last week, we looked at the largest gem in Saturns vast collection satellite treasures, Titan. This week, we will look at other, smaller in the Saturnian system.
They all appear to be geologically dead, devoid of any plate or vulcanism. Compared to the moons of Jupiter, these worlds only subject to mild tidal forces, and their inners cooled solid ago. Some of these moons, however, show signs that they were, at time geologically active.
One of these moons, Enceladus, may still have some activity occuring, changing the appearance of its surface. One possible explanation of this is that the surface is periodically covered from place to place by a liquid coming up through cracks in the surface, filling in the craters, and then freezing. The surface is also yellow, and appears geologically young. The fact that water ice is more common in a ring orbiting around Saturn at the same distance as Enceladus suggests that the liquid filling in these craters could, in fact, be water.
Iapetus is a strange half and half world, with one side as dark as asphalt, and the other side the colr of dingy snow. The dark side may be due to many tiny impacts with mini meteorites kicked up by debris kicked up
by meteorites colliding with Phoebe. This could be seen as the largest game of billiards in the solar system.
This moon is easily visible with a modest backyard telescope. Look in a magazine like Sky and Telescope or Astronomy to find the position of Saturns moons over the course of the month, and see if you can find this world.
All of the moons of Saturn have very low densities, suggesting that they are formed largely from a combonation of ice and rock. The moon Mimas displays a large crack 2 km (about 1 mile) deep. Tethys is marked by a crack extending 3/4 of the way around it's circumference. Hyperion is a strange, disk shaped world about 1/5 as wide across at it's largest point as is Earths lone moon.
See how many of these moons you can find this month.
Clear skies, and good viewing.
