Dwarf planets · Dwarf planet

Pluto

5.9 billion km from the Sun · Light crosses it in 0.0079 seconds

Across

2,377 km

Vs Earth

19% of Earth

Mass

0.22% of Earth

Open Pluto in Cosmic Scale

About

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.

Its heart-shaped glacier, Sputnik Planitia, is made of nitrogen ice.

At a glance

Orbit	248 years
Surface	−230 °C
Moons	Five
Discovered	1930, Clyde Tombaugh

Did you know

1. Sputnik Planitia, the left half of its 'heart', is a glacier of nitrogen ice that churns slowly like a lava lamp.
2. For 20 years of each orbit it is closer to the Sun than Neptune.
3. Some of Tombaugh's ashes are aboard New Horizons, which is now beyond Pluto and still flying.

Real photos

• Pluto's colours, exaggerated to show surface variety — New Horizons, 2015 — NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute · source
• Pluto in extended colour, New Horizons — NASA/JHUAPL/SwRI · source