detached trans-Neptunian object
Sedna
One of the most remote known bodies in the Solar System, a very red world on a huge orbit that never comes near Neptune.
- Distance from Earth today
- 12.25 billion km81.91 AU · light: 11 h 21 min
- Distance from the Sun today
- 12.39 billion km82.81 AU
- As of
- 3 November 2026position from NASA/JPL orbital elements
Where it is today
Top view of the plane of Earth’s orbit, compressed distance scale. Open on the big map with the time slider →
Facts
- Rotation period
- 10.3 h
- Semi-major axis
- 539.3 AU (80.68 billion km)
- Perihelion
- 76.16 AU
- Aphelion
- 1,002.5 AU
- Orbital period
- 12,525 years
- Orbital eccentricity
- 0.859
- Orbital inclination
- 11.9°
- Perihelion passage
- 29 December 2075
- Minimum orbit distance from Earth’s orbit (MOID)
- 75.21 AU (11.25 billion km)
Source of the figures: JPL Small-Body Database (public domain).
Discovery: 2003 – Michael E. Brown, Chad Trujillo, David Rabinowitz
Description
Sedna was discovered in 2003 by Michael Brown, Chad Trujillo and David Rabinowitz at Palomar Observatory. It follows an extremely elongated orbit that takes many thousands of years to complete and, even at its closest, stays far beyond Neptune, so the known planets cannot have placed it there. That puzzle has led to theories involving a passing star, the Sun's birth cluster, or an undiscovered distant planet. Sedna is one of the reddest objects in the Solar System and is currently approaching the closest point of its orbit. It is named after the Inuit goddess of the sea.