Triton size and scale context

Triton is Neptune's largest moon and the only large moon in the Solar System with a retrograde orbit. Scientists think it began as a Kuiper Belt object captured by Neptune, and Voyager 2 found geysers erupting from its intensely cold nitrogen-frost surface. Read its scale context, comparisons, and journey links on the canonical object page.

ErisDwarf planet·2,326 km

PlutoDwarf planet·2,380 km

TritonCaptured icy moon·2,700 km

EuropaIcy ocean moon·3,100 km

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Dwarf planets

Pluto

Pluto is an icy dwarf planet with a surprisingly active surface and atmosphere. New Horizons found nitrogen-ice glaciers flowing across its plains and blue hazes in its sky, showing that even the Kuiper Belt can host dynamic worlds.

Scale fact2,380 kmdiameter

Object class: Dwarf planet
Mass: ~0.0022 Earth masses
Host: Sun
Estimated age: ~4.5 billion years
Composition: Rock, water ice, nitrogen and methane ices
Temperature: ~44 K mean surface

Moons

Triton

Scale fact2,700 kmdiameter

Object class: Captured icy moon
Host: Neptune
Composition: Frozen nitrogen, water ice, rock and metal
Temperature: ~38 K surface

Moons

Europa

Europa is Jupiter's smallest Galilean moon and one of the Solar System's most compelling icy worlds. Its bright water-ice crust is crossed by long fractures, while spacecraft data strongly suggest a salty ocean hidden beneath the surface.

Scale fact3,100 kmdiameter

Object class: Icy ocean moon
Mass: ~0.008 Earth masses
Host: Jupiter
Estimated age: ~4.5 billion years
Composition: Water ice, silicate rock, probable salty ocean
Temperature: ~102 K mean surface