A Fourth Moon Discovered Orbiting Pluto

Written by: Julian Laster
Published on: July 21, 2011
Category: Astronomy

NASA has announced that a fourth moon has been discovered orbiting the dwarf planet Pluto. The new moon has been temporarily assigned the name P4, and is estimated to be 8 to 21 miles in diameter. Charon, Pluto's largest moon is 648 miles in diameter. The frozen planet's other two moons, Nix and Hydra, are estimated to be between 20 and 70 miles in diameter.

Astronomers believe Pluto's lunar system was created when it collided with a similar sized planet as long ago as four billion years.