Against the planet’s rotation.
Triton follows a retrograde orbit around Neptune. That unusual motion supports the idea that it originated elsewhere and was captured. Today it keeps the same face toward Neptune, despite its distinctive direction of travel.
A landscape cold enough for nitrogen ice.
At these temperatures, nitrogen can freeze onto the surface. Pale deposits and low-relief terrain reflect a world very different from terrestrial snowfields. Water ice forms stronger material beneath some of the more volatile surface deposits.
Dark traces on a bright world.
Voyager 2 observed geyser-like activity and dark streaks on Triton. These features showed that extreme cold does not rule out surface change. Seasonal sunlight can influence volatile materials even this far from the Sun.
The interior remains a question.
A captured origin and signs of activity make Triton an intriguing target. Its deep structure is still poorly constrained. Possibilities about internal liquid water should be treated as hypotheses, not as observations of an accessible ocean.