---
title: "Triton: facts, distance and size – Krillion Space"
description: "Triton is Neptune's largest moon and the only large moon in the solar system that orbits backward, against its planet's spin. With sourced facts."
url: https://krilion.app/atlas/triton
language: en-US
---

# Triton

Captured moon. Depth 12 on the Krillion Space voyage, in the Outer Sol.

Triton is Neptune's largest moon and the only large moon in the solar system that orbits backward, against its planet's spin. Scientists think it began as a Kuiper Belt object that Neptune captured, which makes it a close cousin of Pluto.

![Triton at depth 12 in Krillion Space, mapped with Voyager 2 images (NASA / JPL-Caltech / LPI).](https://krilion.app/assets/atlas/triton.webp)

## Fact sheet

- **Type:** Moon
- **Moon of:** Neptune
- **Distance:** About 354,760 km (220,440 miles) from Neptune; Neptune orbits about 4.5 billion km (2.8 billion miles), or 30 AU, from the Sun
- **Size:** Diameter about 2,700 km (1,680 miles)
- **Discovered:** Discovered 10 October 1846 by William Lassell
- **On the voyage:** Depth 12, in the Outer Sol section of the route, between Neptune and Pluto

## Things to know

- Triton circles Neptune in the opposite direction to the planet's rotation, completing one backward orbit in about 5.9 days. ([NASA NSSDC](https://nssdc.gsfc.nasa.gov/planetary/factsheet/neptuniansatfact.html))
- Voyager 2 measured surface temperatures of about -235°C (-391°F), among the coldest found anywhere in the solar system. ([NASA](https://science.nasa.gov/neptune/moons/triton/))
- Voyager 2 caught active geysers on Triton in 1989, showing it is one of the few geologically active moons. ([NASA](https://science.nasa.gov/neptune/moons/triton/))
- Its surface is a crust of frozen nitrogen that reflects about 70 percent of the sunlight that reaches it. ([NASA](https://science.nasa.gov/neptune/moons/triton/))
- William Lassell found Triton on 10 October 1846, just 17 days after Neptune itself was discovered. ([NASA](https://science.nasa.gov/neptune/moons/triton/))

## Missions

Voyager 2 is the only spacecraft to have visited Triton, photographing about two-thirds of its surface during the August 1989 Neptune flyby.

## Sources

- [NASA – Triton](https://science.nasa.gov/neptune/moons/triton/)
- [NSSDC – Neptunian Satellite Fact Sheet](https://nssdc.gsfc.nasa.gov/planetary/factsheet/neptuniansatfact.html)
- [NASA – Voyager 2](https://science.nasa.gov/mission/voyager/voyager-2/)

## On the route

- Previous landmark: [Neptune](https://krilion.app/atlas/neptune)
- Next landmark: [Pluto](https://krilion.app/atlas/pluto)
- [The whole Star Atlas](https://krilion.app/atlas)
- [Fly the voyage yourself](https://krilion.app/d/): every right answer warps your ship one stop deeper.