Astronomical unit
The astronomical unit (AU) is an important measure of length in astronomy. An astronomical unit corresponds approximately to the average distance from the Earth to the Sun. The Earth orbits the Sun in an elliptical path, so the distance is not always the same. One AU is defined as 149,597,870.7 km.
The planets are located at the following distances from the Sun (in AU):
| Planet | Distance to the Sun in AU |
| Mercury | 0.39 |
| Venus | 0.72 |
| Earth | 1 |
| Mars | 1.52 |
| Jupiter | 5.2 |
| Saturn | 9.53 |
| Uranus | 19.2 |
| Neptun | 30.1 |