Pluto has another moon

NASA : Some 5 billion km from Earth, a fourth moon has been found orbiting Pluto. Using the Hubble Space Telescope, astronomers discovered it while they were searching for rings around the icy dwarf planet. The new moon, temporarily designated P4, is Pluto’s smallest, with an estimated diameter of 13–34 km. By comparison, Pluto’s largest moon, Charon, is 1043 km across, and Nix and Hydra are each 32–113 km across. “This is a fantastic discovery,” said Alan Stern of the Southwest Research Institute in Boulder, Colorado. Stern is principal investigator of NASA’s New Horizons mission, scheduled to fly through the Pluto system in 2015. “Now that we know there’s another moon in the Pluto system, we can plan close-up observations of it during our flyby,” he said.