One of
Saturn's moons. See other writeup for technical facts.
Titan is the only planetary moon with a substantial atmosphere. It has been studied by several
scientists, most notably the Dutch astronomer
Gerard Peter Kuiper.
There are many similarities with the Earth's atmosphere. In both atmospheres molecular nitrogen is the main constituent and the surface pressure has an order of 1 bar. Several other trace gases like methane, hydrogen, carbon monoxide, and several molecules are detected. Due to the supposed similarity with the proto-atmosphere of the Earth, paleoclimatologists and exobiologists are interested in the special circumstances which allowed the evolution of the life on the Earth. Especially the complex chemistry of Titan's atmosphere could be the key for the understanding of the evolutional history.
In 1980 Titan has been observed closer by Voyager 1 which also sent the first colour pictures of Titan to the Earth. Voyager 1 identified that Titan carries the national colour of his Dutch discoverer Christiaan Huygens, namely orange. This colour is the result of the thick stratospheric organic haze layer. This thick haze layer covers the whole moon, making an observation of the surface in the visible spectrum impossible. Consequently, many speculations about the surface property arised, ranging from a global ethane ocean to a dry rock surface. This mystery has not been unveiled up to this day.
Titan does not have an own magnetic field, but due to the dense atmosphere a wide-spread ionosphere which interacts with the arriving plasma. Since Titan can be located outside the magnetosphere of Saturn, it is exposed alternately to the solar wind and Saturn's magnetospheric plasma. This large variation of plasma interaction makes Titan quite fascinating.