Titan: Saturn's Smog Moon . ... Titan is the only one of Saturn 's moons with an atmosphere, and one of only two moons in the Solar System with this distinction ( Neptune 's Triton is the other). Titan 's thick cloudy atmosphere is mostly nitrogen, like Earth 's, but contains much higher percentages of "smog-like" chemicals such as methane and ethane. ... The organic nature of some of the chemicals found in Titan's atmosphere cause some to speculate that Titan may harbor life! ...