Find out about the solar system and learn the order of the planets with a song in this video ... and dwarf planets such as Pluto.

Our solar system has eight planets but in recent years, astronomers have theorised there could well be a ninth planet that's hiding in our solar system we've not been able to see yet.

New Horizons principal investigator Alan Stern says, "Pluto is showing us a diversity of landforms and complexity of processes that rival anything we've seen in the solar system." As the craft ...