| While Titan resembles the rocky inner planets, Saturn is mostly atmosphere. |
| The eighth planet from the sun, its gaseous structure contrasts with the rocky inner planets. |
| A planetary transit is like an eclipse of the Sun, with the inner planets Mercury or Venus becoming the obscuring objects, instead of the Moon. |
| This explains the composition of much of the asteroid belt as well as the inner planets. |
| It is believed that eventually the sun will expand into a red giant, swallowing all of the inner planets, and destroying all life on earth. |
| It is also known that the inner planets are dense and rocky, whereas the outer planets are composed largely of frozen gases. |
