Every Hidden World In Our Solar System Explained In 15 Minutes

Titan The only moon in the solar system with a thick atmosphere is also the only world other than Earth known to have standing liquid on its surface. It is the largest moon of Saturn and the second largest in the solar system, bigger than the planet Mercury. Its atmosphere is denser than Earth's and composed mostly of nitrogen, wrapped in a thick orange haze that hides the surface completely from ordinary cameras. For most of the space age, no one knew what lay beneath that haze.