Pluto isn’t the only thing puzzling scientists — its moons behave pretty unexpectedly, too, NASA researchers also announced at the 47th Annual Meeting of the American Astronomical Society’s Division for Planetary Sciences. Pluto has one large moon, Charon, and four smaller moons: Styx, Nix, Kerberos, and Hydra. Pluto and Charon actually orbit around each other because they are pretty similar in size. The four smaller moons spin wildly around the planetary system. Hydra, for example, rotates 89 times as it completes one trip around Pluto. The moons also wobble like "spinning tops," thanks to the gravitational pulls of both Pluto and Charon. NASA thinks that the four wobbly moons are the results of mergers of two or more moons — meaning Pluto once had even more satellites than it does now.