The solar system is made up of the Sun and objects that orbit around it, including eight planets that can be drawn in a diagram from closest to furthest: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune. The solar system formed around 4.6 billion years ago, while the universe is estimated to have formed 13.8 billion years ago. The Jovian planets of Jupiter, Saturn, Uranus and Neptune are large gas giants, while the Terrestrial inner planets of Mercury, Venus, Earth and Mars are smaller and rocky.