Eris

Eris — dwarf planet, shown live in Cosmoscope, a real-time 3D map of the universe.

The discovery that demoted Pluto. Slightly smaller but more massive than Pluto, this frozen world wrapped in methane ice forced astronomers to invent the term “dwarf planet”.

Radius
1,163 km — nearly Pluto’s twin
Discovered
2005 — Mike Brown’s team
Year
~559 Earth years
Distance
38–98 AU (highly eccentric)
Moon
Dysnomia
Region
Scattered disc

Seeing Eris in real time

Cosmoscope puts Eris at its true position in the solar system, computed from JPL-derived ephemeris and updated continuously. Open the live 3D view to see, in real time, how far Eris is from the Sun and from Earth right now, how many minutes or hours light takes to cross that gap, and how fast it is moving along its orbit. Scrub the timeline to place Eris where it was on any past date, or where it will be years from now.

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