Mark Megahan
NASA’s Cassini project, sent far out into space just to capture close up shots of Saturn and her moons, beamed back a once in a lifetime encounter. Along with the famous rings, Saturn has a whole bunch of moons. At last count, 82 have confirmed orbits. As the probe sailed by, three of them lined up in a spectacular pose.
Cassini triple crescent
There’s a huge range of size and composition between Saturn’s many moons. From tiny lumps of rock to the magnificent Titan, which holds it’s own atmosphere and could support life, even human life. Not on the surface though.
The methane tornadoes are only one thing to worry about but it would make a great galactic gas station. Cassini was lucky enough to image Titan, Mimas, and Rhea. The probe was only 2.7 million miles from Titan when the shutter opened. In astronomical terms, that’s not far.
The Cassini mission wasn’t entirely an American project. It was done in cooperation with the European Space Agency and the Italian Space Agency.
Thanks to them, they proved that there are flowing rivers someplace other than on Earth. The eerie difference is that instead of water carving out the channels, methane and ethane run down Titan’s mountainsides.
Cassini used radar to “generate images of the surface,” while “Huygens landing station landed on the surface of the distant satellite” that sent home pictures from the surface.
As of now, “Titan is the only place in the solar system besides Earth where there is an active a hydrological system that includes rain, rivers, lakes and seas.”
Plate tectonics
Another thing that Titan has in common with earth is a geology based on plate tectonics. Just like the San Andreas Fault in California, Strike-slip faulting is “frequent” on Titan. Cassini did radar surveys which confirm that a “thick layer of rock-hard water ice covers Titan.”
Because of the flowing hydrocarbons, the required “tidal load on Titan, the orientations of potential faults, crustal characteristics (including pore fluid pressure), and the stress required to cause the surface material to break or fracture” are all present.
Cassini revealed that “strike-slip faulting is now occurring on Titan. some channels cut into the icy bedrock by hydrocarbon rivers show an offset in their path along shear planes, similar to ‘beheaded channels’ in the desert that looked like they were once part of the original canyon before earthquakes shoved them aside, which occur along the San Andreas Fault.”
One of Jupiter’s moons, Europa, is also thought to exhibit plate tectonics, “with huge ice plates floating in a massive interior ocean.”
Another interesting fact about Titan, which wasn’t studied by Cassini, is the question of whether the largest moon gave Saturn it’s distinctive tilt. Earth gets it’s tilt from “massive impacts with other rocky objects” early in our history.
The theory is controversial but some scientists think “an orbital resonance with Saturn could have occurred recently, simultaneously changing the moon’s orbit and forcing a nearly upright Saturn to fall sideways.”
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