Sirens of Titan
This is Titan, Saturn's haunting and and mysterious moon. Titan is arguably he most fascinating place outside Earth in our solar system. This image is just stunning, in my opinion- more so even than those of Mars, which rightfully garners a lot of attention. Titan is an active, vital object, a "somewhere" outside Earth we instinctively recognize as a world. A world that beckons us to explore. A world frozen and hostile to us, no doubt, with lakes of liquid methane and ethane lapping on frigid shores.
Still, Titan alive in a way our own moon is not. The Cassini-Huygens mission is quietly producing exciting and compelling science, and the results are worth a look. You can find more here.
Titan is the second-largest moon in the solar system (behind Jupiter's Ganymede, which is pretty boring and barren by comparison) and is larger than any of the dwarf planets. It is the only moon with a dense atmosphere. The clouds may be made of ethane, and the lakes, though not absolutely confirmed, seem to exist near the poles, and are probably hydrocarbons. As a chemist, I find this particularly exciting. Titan is clearly cold, and hostile, but with all that organic material, something interesting is going on, perhaps supporting a primitive form of life.