If you were going to build a death star, then hide it, what would it look like? SciAm Observations today has an array of desktop backgrounds of the moon Iapetus, which orbits Saturn. Iapetus is an especially fascinating moon for many reasons. For starters, it has a giant impact crater. Also there is an equatorial ridge which encircles the entire moon, making it slightly resemble a walnut. The moon is heavily pockmarked with craters.
Image courtesy of NASA and JPL. Taken by the Cassini probe.
Imagine for a moment, you are one of the first explorers of Iapetus in your advanced spacesuit that lets you move about freely (and with booster packs). You land in the center of the large impact crater, which lies in the bright region of the planet known as Roncevaux Terra. Beneath you is a deep crust of ice and the temperatures outside are less than -220 degrees Fahrenheit. Across the sky hangs Saturn, like a giant. Even at night on Iapetus, Saturn’s light is bright enough to guide you. You stare off into the distance. About 150 miles away is the scarp of the crater, the wall that climbs up out of it. It’s basically a ring of giant mountains, the only visible feature in all directions. Mountains over 9 miles high. Off in the direction of the pole, the mountains dip slightly, leading off to another, smaller impact crater.
You decide to head towards the equator of the moon. After many long bounces (the gravity is 1/50th of Earth’s), you make the long journey over the icy, pockmarked landscape. In a few places, there was no ice and the ground was a dingy reddish-brown. Finall, in the distance you see the first signs of the equatorial ridge creeping over the horizon. As you get closer, it stretches into the sky. The ground stays mostly flat as you approach, there are no foot hills. Once you finally reach the end of the plain and look up at the peaks. They are towering over you at a staggering height of 12 miles.
Using your booster packs and the low gravity, you make it to the top and survey this bizarre world. Half covered in ice and half in dirt, like a spherical yin-yang symbol. Above you are the swirling clouds of Saturn and the rings, glittering in the morning light. A very small, but bright sun creeps over the horizon, turning this small world into a glittering polar landscape.
Iapetus was named after a titan from Greek Mythology and many of the craters are named after characters from a French novel. Iapetus was the father of the titans Atlas and Prometheus. The dark region of Iapetus was named after Giovanni Domenico Cassini, the Italian-French astronomer who discovered the moon on October 25, 1671 and first theorized that half of Iapetus must be dark and half light, since it seemed to disappear when it was on one side of Saturn. He named it one of the Louisian Stars (the Sidera Lodoicea) in honor of King Louis XIV.
What is bizarre to mean is its strange resemblance to the death star from Star Wars. If you wanted to build a death star and then hide it. What would it look like? The large impact crater would be the location of the giant laser used to destroy worlds. The equatorial ridge corresponds to the equatorial gulley on the death star. (And while this similarity occurred to me independently, I am by no means the first person to make this link as a quick google search will reveal.) Actually, it is usually Saturn’s moon Mimas that has analogies drawn to it as being the death star moon.
And if you’re in the mood for a really hilarious spoof of Star Wars epsiode 3, check out this video. It will also help you understand the post title. Skip to 2:13 (remaining time) if you’re too impatient to watch it all.