Pluto was found in 1930 by Clyde Tombaugh, a 24-year-old farm boy turned astronomer. The name was suggested by Venetia Burney, an 11-year-old girl in England.
For 76 years it was the ninth planet. In 2006 astronomers decided it was one of many small worlds out here, and called it a dwarf planet instead.
Then in July 2015 the New Horizons spacecraft flew past, and Pluto turned out to be amazing. There is a giant heart on its face, the left half a plain of frozen nitrogen 1,000 km wide that slowly churns like a lava lamp.
It has mountains of water ice as tall as the Alps, and a thin blue haze for a sky.
Pluto takes 248 years to go once around the Sun. It hasn't finished a single lap since we found it, and won't until 2178.
If you stood here
The Sun would be a dazzling star, bright enough to read by, but about a thousand times dimmer than on Earth. At −230 °C, the air itself freezes onto the ground.
- Width
- 2,377 km
- One day
- 6 Earth days, spinning backwards
- One year
- 247.9 Earth years
- Moons
- 5
- Temperature
- about −230 °C
- 70 kg on Earth weighs
- 4 kg here
