Scientists are apparently a little shocked that a dwarf planet a small as Pluto could have such a rich array of moons, even though most of the moons are no larger than your average asteroid (the exception being Charon, which is half the size of Pluto and nearly dwarf planet size itself).
Image shows five moons orbiting the icy dwarf planet Pluto
P5 isn't a big moon and isn't particularly interesting--it's just 15 miles across and irregularly shaped--but its existence is still interesting. It is also one of, if not the, smallest object we have spotted that far out.
Pluto remains a point of contention to many simply because it was called a planet for so long. The problem is, Pluto is pretty tiny. If we considered Pluto a planet, there were a bunch of other rocks floating in our solar system which would qualify for planethood, too, for example Ceres in the asteroid belt and Eris, which is actually larger than Pluto.
So planets were redefined to be rocks that had cleared their orbit, much as the rest of the planets have. Pluto, Ceres, and Eris haven't; Earth, Mars, and the rest have.
The Verge Photo by : NASA