Titan has eclipsed Mars. Not literally, mind you, but conceptually. With active surficial geology the likes of which are known only to Earth, and considering the recent discovery of possible biochemical signatures of alien life, to me Titan has become the most interesting exploration destination in the solar system.
Take the above image, for starters. Whereas most other rocky worlds in our solar system offer an unbridled view of craters, mountains, and ancient plains, Titan’s dynamic, hazy atmosphere betrays little. Truly, the giant moon, which is larger than the planet Mercury itself, is a world shrouded in mystery.
-And, the more we learn about Titan, the more we have reason to believe it is the most Earth-like world this side of a few trillion miles.
(As an aside: My hat is off to the CICLOPS Cassini spacecraft imaging team for giving us real-life pictures like this. Thanks to them, images from our science today trump the science fiction special effects of a decade ago.)
Unlike Mars, Titan offers us lakes, rivers, clouds, and rain – A full, living hydrologic cycle that is active not billions of years ago, but today. (Yes, “hydrologic cycle” is perhaps a slight misnomer, because on Titan the active fluid is methane/ethane, not H2O, but the process appears to be the same.) -And, perhaps most excitingly, scientists have recently discovered evidence that may indicate methane-based alien biochemistry at work.
Specifically, a flux of hydrogen molecules toward Titan’s surface, (rather than away as would be expected,) may indicate the consumption of the gas on Titan (as aerobic life on Earth consumes oxygen); A distinct lack of the hydrocarbon acetylene, one of the most potent chemical energy sources on Titan, may betray that hydrogen-breathing, methane-based life is consuming acetylene as food.
And at least hypothetically, all of the potential chemistry checks out.
If all of this together doesn’t spell impetus for further investigation, I can’t imagine what does. To boot, because it is so cold out at Saturn’s distance from the Sun and despite Titan’s weaker gravity, the condensed atmospheric pressure on Titan is practically identical to what we experience on Earth, making human exploration all the more feasible.
Have spacesuit, will travel. Titan or bust.