| The eighth planet from the sun, its gaseous structure contrasts with the rocky inner planets. |
| This explains the composition of much of the asteroid belt as well as the inner planets. |
| It is also known that the inner planets are dense and rocky, whereas the outer planets are composed largely of frozen gases. |
| Mars is the only one of the inner planets that can be made habitable simply by changing its climate. |
| The inner planets all formed from the disk of gas and dust, the solar nebula, that surrounded our young sun. |
| 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. |
