In our solar system, nine planets circle around our Sun. The Sun sits in the middle while the planets travel in circular paths (called orbits) around it. These nine planets travel in the same direction (counter- clockwise looking down from the Sun's north pole). The picture on the right shows the different paths and positions of each planet
- The inner solar system contains Mercury, Venus, Earth and Mars. These four planets are closest to the Sun.
- The outer solar system contains Jupiter, Saturn, Uranus, Neptune and Pluto are much larger planets and are very gaseous in nature. Pluto is the smallest planet and is the farthest away from the sun.
The inner planets are separated from the outer planers by the Asteroid Belt. Beside, many scientists believe that our Solar System is over 4.6 billion years old.