Tritón

Tritón is a moon of Neptune, discovered by astronomer William Lassell in 1846, just seventeen days after the discovery of Neptune itself. It is the largest of Neptune's moons and the seventh-largest moon in the Solar System. Tritón is unique among large moons for its retrograde orbit, meaning it orbits Neptune in the opposite direction to the planet's rotation. This suggests that Tritón may have been a dwarf planet or Kuiper Belt Object captured by Neptune's gravity.

The surface of Tritón is remarkably varied, featuring vast plains, rugged terrains, and cryovolcanoes. These cryovolcanoes are thought to erupt nitrogen gas and dark, smoky material from beneath the surface. The moon's surface is also covered in a thin atmosphere of nitrogen, with trace amounts of methane. Its temperature is extremely cold, averaging around -235 degrees Celsius (-391 degrees Fahrenheit).

Observations by the Voyager 2 spacecraft in 1989 provided the first close-up views of Tritón, revealing its geologically active nature and its complex surface features. Despite its frigid temperatures, the presence of active geysers and a varied landscape indicates ongoing geological processes. Tritón's retrograde orbit and composition continue to make it a subject of great interest for planetary scientists studying the formation and evolution of the outer Solar System.