William Lassell discovered it in 1846, and initially, it was thought that Pluto was the satellite of another planet because of this body's closeness in its period of rotation to the ninth planet.
It is now know that this satellite has an extremely thin atmosphere composed primarily of nitrogen and methane. When Voyager 2 flew by it in 1989, it was seen to have a landscape akin to the rind of a cantaloupe and to have a surface temperature of minus 240 degrees Celsius, possibly making it the coldest body in the solar system. William Lassell discovered it in 1846, and initially, it was thought that Pluto was the satellite of another planet because of this body's closeness in its period of rotation to the ninth planet. FTP, name this largest satellite to exhibit retrograde motion, also the largest moon of Neptune.
It is now know that this satellite has an extremely thin atmosphere composed primarily of nitrogen and methane.
{Triton}