Pluto
2,377 kmacross — smaller than the Moon
Pluto is 2,377 km across — smaller than Earth’s Moon — and orbits the Sun at an average of 39.48 AU (about 5,906,123,908 km), swinging between 29.7 and 49.3 AU on a stretched, tilted orbit. Sunlight takes about 5.5 hours to reach it. Discovered in 1930, it was the ninth planet until it was reclassified as a dwarf planet in 2006.
▶ Visit Pluto in 3D
What kind of world is it?
Pluto is the best known of the dwarf planets: a small, cold world of rock and ice out in the Kuiper Belt, the ring of frozen bodies beyond Neptune. For a long time it was just a faint dot, but in 14 July 2015 NASA’s New Horizons spacecraft flew past and revealed a startlingly complex place — nitrogen-ice glaciers, mountains of frozen water, a thin haze-layered atmosphere, and a vast pale plain shaped like a heart. Its largest moon, Charon, is over half Pluto’s size, so the two orbit a point in the empty space between them, more a double world than a planet and its moon.
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Pluto by the numbers
Diameter
2,377 km
Average distance from Sun
39.48 AU
Closest / farthest
29.7 – 49.3 AU
Sunlight travel time
≈ 5.5 hours
Mass vs Earth
about 0.2%
Surface gravity
0.62 m/s²
Temperature
−229 °C
A day lasts
6.4 Earth days
A year lasts
248 Earth years
Known moons
5 (Charon is the largest)
Pluto is so small that seven moons in the solar system are bigger than it — Ganymede, Titan, Callisto, Io, our own Moon, Europa and Neptune’s Triton. By width, Earth is about 5.4× larger.
See it for yourself: in the interactive view Pluto sits far beyond Neptune on its tilted, stretched orbit — switch to 1:1 scale and it becomes an all-but-invisible speck, 5.5 light-hours from the Sun.
Keep going
✓ Facts verified July 2026
Every figure on this page is a real, rounded value checked against primary sources. Found something out of date? See how we keep it accurate.