text: what is the hole nine solar systems? i don't no it mercury, venus, earth, mars, jupiter, saturn, uranus, neptune and pluto.  the first 4 are small rocky planets.  the next 4 are called gas giants because they are very large planets covered by gas, with small rocky or metallic cores.  pluto is the closest large member of a group of objects in the outer solar system called kuiper belt objects (or trans-neptunian objects).