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Pluto's 5 Moons Explained: How They Measure Up (Infographic)

Dwarf planet Pluto has one giant moon, Charon, but now is known to have four more tiny satellites.
Dwarf planet Pluto has one giant moon, Charon, but now is known to have four more tiny satellites.
(Image: © Karl Tate, SPACE.com Contributor)

Pluto is the second-largest object in the outer reaches of our solar system, barely smaller than another dwarf planet, Eris.

Charon, Pluto’s most massive moon, was discovered in 1978. Charon has a diameter of 648 miles (1,043 kilometers) and orbits Pluto at a distance of 12,200 miles (19,640 kilometers). 

Charon completes one orbit in 6.4 Earth days, which is the same time it takes Pluto to rotate once on its axis. As a result, the two bodies are tidally locked, eternally facing one another, just as our moon always presents the same face to Earth. [Photos: Pluto and its Moons]

In recent years, other small moons of Pluto have been discovered orbiting the distant dwarf planet. Nix and Hydra, both discovered in 2005, each have a diameter of about 25 miles (40 kilometers).

Kerberos, found in 2011, is smaller at 8 to 21 miles in diameter (13 to 34 kilometers). The latest discovery, Styx, was found in 2012 and is the smallest moon so far, only 6 to 15 miles across (10 to 25 kilometers).

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