Neso

Neso — moon orbiting Neptune, explore its interactive 3D model in Cosmoscope.

Explore Neso in a live 3D Solar System. Follow its calculated motion and inspect real astronomical data, distances and orbital facts.

Neso wanders farther from its planet than almost any other known moon: so far that one backwards lap takes almost 27 years. Out here the Sun’s pull keeps reshaping its orbit; the path shown is the ellipse it follows today.

Radius

~15 km

Orbit

49.9 million km from Neptune

Period

26.8 years — retrograde

Discovered

2002 — Holman, Kavelaars, Grav and colleagues, Chile

Distance

About 50 million km on average — a third of the Earth–Sun distance

Orbit shape

Backwards, tilted and loose; the Sun’s pull keeps changing it

Family

Neso group, with Psamathe and S/2021 N1

Size

About 30 km across, estimated from its brightness

Explore Neso in 3D

Cosmoscope places Neso in the Solar System using astronomical ephemeris or orbital elements, updated for the simulation time. Explore its calculated motion, distance and orbital facts in the interactive 3D view. Accuracy depends on the orbital model and its valid time range.