It has an extremely thin atmosphere. Nitrogen ice particles may form thin clouds a few kilometers above the surface.
Triton is scarred by enormous cracks.
Voyager 2 images showed active geyser like eruptions spewing nitrogen gas and dark dust particles into the atmosphere. Some scientists suggest that Triton may have once been a planet on its own circling the Sun, and that it was captured by interaction with the combined gravitational influences of the Sun and Neptune to become a moon. Voyager 2 obtained this color image of Neptune's large satellite Triton during its close flyby on Aug. 25, 1989. From the ragged edge of the polar cap northward the satellite's face is generally darker and redder in color. This coloring may be produced by the action of ultraviolet light and magnetospheric radiation upon methane in the atmosphere and surface.