Body diameters to scale. Positions and surface artwork are illustrative; Saturn’s rings are excluded.
A change of perspective
5.4781× the diameter. See how the two worlds measure up.
Diameter is a distance across an object. Volume grows with the cube of that distance.
Choose a size to bring this comparison down to Earth.
Eris: Adopted spherical diameter: 2,326 ± 12 km from stellar occultation observations reported in 2011. Used here as a volume-equivalent mean diameter under the near-spherical assumption: the diameter of a sphere with the same volume. This is not an independently measured equatorial or polar diameter; the quoted precision depends on the shape assumption.
Earth: Twice the source mean radius; body diameter only, excluding rings.
Adopted spherical diameter: 2,326 ± 12 km from stellar occultation observations reported in 2011. Used here as a volume-equivalent mean diameter under the near-spherical assumption: the diameter of a sphere with the same volume. This is not an independently measured equatorial or polar diameter; the quoted precision depends on the shape assumption.
Eris is approximately 2,326 kilometres across. Observations of a November 2010 stellar occultation indicated a nearly spherical body; ESO reported a diameter uncertainty of 12 km. This page adopts that result for size comparisons. Read ESO’s measurement report.
The displayed ice appearance is illustrative artwork, not a resolved surface photograph.
At a scale of 1 centimetre for every 1,000 kilometres, Eris would measure about 2.33 centimetres across. This is calculated by dividing the adopted diameter by 1,000; the reported ±12 km corresponds to ±0.12 mm in that model.
For another object, divide 2,326 km by its diameter in kilometres to obtain the diameter ratio. Keep both measurements on the same basis: mean diameter and equatorial diameter can differ. A diameter ratio describes width; a spherical volume ratio is its cube.
It is the diameter, measured across the body through its centre. The corresponding radius is half that value, approximately 1,163 km.
Why is the diameter marked approximate?
The measurement has uncertainty, and its interpretation as a volume-equivalent mean diameter assumes a nearly spherical shape. It should not be read as an exact dimension in every direction.