It has a very large, thick atmosphere, and in fact, its surface environment was believed to be more like the environment we have here on the Earth, or at least had in the past, than any other body in the solar system.
Ima vrlo obilnu, gustu atmosferu. Zapravo, vjerovali smo da je okoliš na njegovoj površini sličniji okolišu kakvog imamo na Zemlji ili bar okolišu kakav je bio na Zemlji u prošlosti, od bilo kojeg drugog nebeskog tijela u Sunčevom sustavu.