Titan (moon) Titan (moon) Titan is the largest moon of Saturn. It is the only moon known to have a dense atmosphere, and the only object in space, other than Earth, where clear evidence of stable bodies of surface liquid have been found. Titan is the sixth gravitationally rounded moon from Saturn. Frequently described as a planet-like moon, Titan is 50% larger than Earth's moon and 80% more massive. It is the second-largest moon in the Solar System after Jupiter's moon Ganymede, and is larger than the smallest planet, Mercury, but only 40% as massive. Discovered in 1655 by the Dutch astronomer
Small Solar System body with the exception of the dwarf planets Pluto, Haumea, Makemake, Eris, and others that may turn out to be dwarf planets. It is not presently clear whether a lower size bound will be established as part of the definition of small Solar System bodies in the future, or if it will encompass all material down to the level of meteoroids, the smallest macroscopic bodies in orbit around the Sun. (On a microscopic level there are even smaller objects such as interplanetary dust, particles of solar wind and free particles of hydrogen.) Except for the largest, which are in hydrostatic equilibrium,