Our solar system formed about 4.6 billion years ago from a cloud of gas and dust. Today, it includes the Sun, eight planets, dwarf planets, moons, asteroids, comets and countless smaller objects.
The Sun sets the scene
The Sun contains the overwhelming majority of the solar system's mass. Its gravity keeps planets and smaller objects in orbit, and its energy shapes the environments of the worlds nearby.
Four rocky planets
Mercury, Venus, Earth and Mars are terrestrial planets. Compared with the giant planets, they are relatively small and have solid surfaces. Their atmospheres, temperatures and geological histories vary dramatically.
Four giant planets
Jupiter and Saturn are gas giants; Uranus and Neptune are ice giants. Some have extensive moon systems, rings and dynamic atmospheres. Saturn's rings are especially recognizable, but all four giant planets have ring systems.
| Planet | Broad type | Notable feature |
|---|---|---|
| Mercury | Rocky | Closest planet to the Sun |
| Venus | Rocky | Dense, heat-trapping atmosphere |
| Earth | Rocky | Surface liquid water |
| Mars | Rocky | Ancient water-shaped terrain |
| Jupiter | Gas giant | Largest planet |
| Saturn | Gas giant | Prominent rings |
| Uranus | Ice giant | Unusually tilted rotation axis |
| Neptune | Ice giant | Distant, windy atmosphere |
What can you actually see?
Venus and Jupiter can become strikingly bright. Mars can look distinctly reddish, while Saturn appears as a point of light to unaided eyes. Precise visibility depends on date, location and weather. Use a current sky chart rather than relying on a fixed schedule.