| A | B |
|---|
| asteroid belt | located between Mars and Jupiter |
| ellipse | the shape of a planet's orbit |
| rotation | determines the length of a planet's day |
| Mercury | closest planet to the sun |
| oort cloud | located beyond the orbit of Pluto-the birthplace of comets |
| mass | determines the strength of an object's gravity |
| Pluto | is now classified as a dwaft planet |
| revolution | determines the length of a planet's year |
| gravitational field | area around an object in which it's gravity can be felt |
| Saturn | 6th planet from the sun |
