Cosmic Scale
Pluto
Dwarf planet · 5.9 billion km from the Sun
How big is Pluto?
Pluto is about 2,377 km across.
See Pluto in 3D, at true scale
Pluto was the ninth planet for 76 years, and is now the best-known dwarf planet. In 2015 New Horizons raced past and turned a fuzzy dot into a world with nitrogen glaciers, water-ice mountains and a blue haze.
At a glance
| Diameter | 2,377 km |
|---|---|
| Mass | 1.30 × 10²² kg |
| Diameter compared with Earth | 0.187 × Earth |
| Orbit | 248 years |
| Surface | −230 °C |
| Moons | Five |
| Discovered | 1930, Clyde Tombaugh |
Good to know
- Sputnik Planitia, the left half of its 'heart', is a glacier of nitrogen ice that churns slowly like a lava lamp.
- For 20 years of each orbit it is closer to the Sun than Neptune.
- Some of Tombaugh's ashes are aboard New Horizons, which is now beyond Pluto and still flying.