* Terrestrial Planets: These are rocky planets with solid surfaces. They are typically smaller and denser than the gas giants. The terrestrial planets in our solar system are Mercury, Venus, Earth, and Mars.

* Gas Giants: These are large planets composed primarily of gas, such as hydrogen and helium. They are much larger than the terrestrial planets and have no solid surface. The gas giants in our solar system are Jupiter, Saturn, Uranus, and Neptune.