Triton and Neptune,montage image. Triton is the largest moon of the planet Neptune (blue). Neptune,the eighth planet from the Sun,has a diameter of over 48,000 kilometres. It is considered an ice giant,with an icy interior and an atmosphere of hydrogen and helium. Triton consists of ices and rocks. It has a diameter of around 2700 kilometres,and orbits Neptune at a distance of around 355,000 kilometres. Triton's surface is mostly covered by nitrogen frost mixed with traces of condensed methane,carbon dioxide,and carbon monoxide. The streaks are due to wind-borne deposits in the tenuous atmosphere. These images were obtained by the Voyager 2 spacecraft,which made its closest approach to Neptune on 25 August 1989 |