Proteus

Proteus — moon orbiting Neptune, shown live in Cosmoscope, a real-time 3D map of the universe.

Bigger than Mimas yet still a lump: Proteus sits right at the size where gravity almost — but not quite — pulls a world into a sphere.

Radius
210 km
Orbit
118k km from Neptune
Period
1.12 days
Rank
Neptune’s second-largest moon
Shape
About as big as a body can be and stay lumpy

Seeing Proteus in real time

Cosmoscope puts Proteus 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 Proteus 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 Proteus where it was on any past date, or where it will be years from now.

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Interactive universe
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