Solar system guide
SOLAR SYSTEM GUIDE
This solar system guide was produced by Sydney Observatory. You can use the Scribd version, below, or you can download the pdf here.
Space exploration enables new discoveries to be made and causes terms to be redefined, so you may find slight differences in the information in this solar system guide and elsewhere. For example, new moons orbiting planets in our solar system continue to be found, so the numbers change. Also, definitions change over time. Pluto was considered to be a planet until 2006, when it was redefined as a dwarf planet, so the number of planets was reduced from nine to eight.