~ Pluto is a small, icy "dwarf planet". Scientists are still unsure as to exactly what it's made of.
~ Pluto has not yet been visited by a spacecraft, but there's one on the way!
~ Depending on how far along it is in its orbit (path around the Sun), Pluto can be either the eighth or ninth planet. Pluto's orbit is kind of wacky, and it sometimes crosses in front of Neptune. When Pluto does this, Neptune is behind Pluto - hence, it is the eighth planet for a short time.
~ Pluto has one moon. It's called "Charon."