Eris size and scale context

Eris is a distant dwarf planet in the scattered disk beyond Neptune. Its discovery helped trigger the 2006 planet-definition debate, and its tiny moon Dysnomia lets astronomers measure its mass. Read its scale context, comparisons, and journey links on the canonical object page.

CeresDwarf planet·940 km

IapetusTwo-toned icy moon·1,470 km

ErisDwarf planet·2,326 km

PlutoDwarf planet·2,380 km

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Between the smallest and the largest, perspective is everything.

About

Scale of Space is a scroll-based journey through the universe, placing objects on a single logarithmic scale so you can compare size across an unbroken range.

Guides turn parts of that scale into curated essays, while focused views let you explore the same range through specific groups of objects.

Editorial

Solar System Planets From Electron to Atoms Stars To Scale Birth And Death Of Stars Black Holes To Scale

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Planets of the Solar System Stars of the Universe Black holes Subatomic scale

Open Scale of Space Browse all comparisons

Between the smallest and the largest, perspective is everything.

About

Scale of Space is a scroll-based journey through the universe, placing objects on a single logarithmic scale so you can compare size across an unbroken range.

Guides turn parts of that scale into curated essays, while focused views let you explore the same range through specific groups of objects.

Editorial

Solar System Planets From Electron to Atoms Stars To Scale Birth And Death Of Stars Black Holes To Scale

Views

Planets of the Solar System Stars of the Universe Black holes Subatomic scale

Open Scale of Space Browse all comparisons

Moons

Iapetus

Iapetus is Saturn's third-largest moon and one of its strangest, with a bright trailing hemisphere and a dark leading hemisphere. Its slow rotation, distant orbit, and giant equatorial ridge make it a moon defined by contrast.

Scale fact1,470 kmdiameter

Object class: Two-toned icy moon
Host: Saturn
Composition: Water ice and rock with dark carbon-rich surface material

Dwarf planets

Eris

Eris is a distant dwarf planet in the scattered disk beyond Neptune. Its discovery helped trigger the 2006 planet-definition debate, and its tiny moon Dysnomia lets astronomers measure its mass.

Scale fact2,326 kmmean diameter

Object class: Dwarf planet
Mass: ~0.0028 Earth masses
Host: Sun
Estimated age: ~4.5 billion years
Composition: Rock and ice

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