More Moon and Saturn
 Mimas, one of the largest moons of Saturn, shows the scars of billions of years of impacts by rocky debris in this close-up view from the Cassini spacecraft, with Saturn's rings in the background. The largest impact crater, which is on the other side of the moon, inspired researchers to nickname Mimas the "Death Star Moon," because it resembles the giant space stations of Star Wars fame. The surface of Mimas is one of the most thoroughly battered in all the solar system, which tells geologists that nothing has happened on the moon itself, such as melting or volcanic eruptions, to erase the craters. [NASA/JPL/SSL]
Mimas is a ball of ice and rock that's about as wide as Iowa.
Like many of the moons of the solar system, the surface of Mimas is covered with craters -- the scars of collisions with smaller objects. Most of the craters aren't all that interesting. But one has earned Mimas a nickname: the Death Star Moon. That's because the crater makes the little moon look like the famous Star Wars battle stations.
The crater is about 80 miles across -- one-third the diameter of Mimas itself. It's six miles deep, and has a central mountain peak that's about four miles high.
The crater formed when an asteroid or comet slammed into Mimas. The impact was so powerful that it probably cracked the moon all the way through. Had it been just a little more powerful, Mimas would've been pulverized -- perhaps forming a new ring around Saturn.
Instead, Mimas appears to sweep out a wide gap in the rings, as some of the tiny particles that make up the rings march in step with the Death Star Moon.
Saturn is in fine view early tomorrow. It's in the east at first light, standing almost directly above our own Moon. Saturn looks like a bright golden star, shining steadily in the growing light of dawn.
Script by Damond Benningfield, Copyright 2006, 2009
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