Natural satellite achieved hydrostatic equilibrium, and Uranus has five. It has been suggested that some satellites may potentially harbour life. Among the identified dwarf planets, Ceres has no known natural satellites. Pluto has the relatively large natural satellite Charon and four smaller natural satellites; Styx, Nix, Kerberos, and Hydra. Haumea has two natural satellites, and Eris and Makemake have one each. The Pluto–Charon system is unusual in that the center of mass lies in open space between the two, a characteristic sometimes associated with a double-planet system. The seven largest natural satellites in the Solar System (those bigger than 2,500 km across)
The Pluto Files The Pluto Files The Pluto Files: The Rise and Fall of America's Favorite Planet is a book written by the astrophysicist and Hayden Planetarium director Neil deGrasse Tyson. The book is about Pluto, which was demoted to the status of dwarf planet in August 2006 by the International Astronomical Union, thereby depriving it of its planet-hood. The book also focuses on the fact that many Americans rallied their support for this icy dwarf on the edge of the Solar System because it was discovered by an American. The book was given a good review by Jon Stewart in a guest