Eight planets orbit the Sun: four small rocky worlds and four giants. Meet them all, together with their moons, dwarf planets, asteroids and comets.
The Solar System formed about 4.6 billion years ago from a cloud of gas and dust. Most of the material ended up in the Sun, the rest formed eight planets, their moons and countless smaller bodies.
In the image above, the Cassini spacecraft looked at Saturn with the Sun behind it. One of the tiny dots near the rings is Earth, about 1.4 billion kilometres away.
| Planet | Mean distance from the Sun | Diameter | One orbit (year) |
|---|---|---|---|
| Mercury | 0.39 au | 4,879 km | 88 days |
| Venus | 0.72 au | 12,104 km | 225 days |
| Earth | 1.00 au | 12,742 km | 365.25 days |
| Mars | 1.52 au | 6,779 km | 687 days |
| Jupiter | 5.20 au | 139,820 km | 11.9 years |
| Saturn | 9.54 au | 116,460 km | 29.5 years |
| Uranus | 19.2 au | 50,724 km | 84 years |
| Neptune | 30.1 au | 49,244 km | 165 years |
The diameter is measured at the equator for Earth and the giant planets, and as a mean value for Mercury, Venus and Mars.