Our universe is huge in size. It has millions of galaxies in it. The solar system is situated in the Milky Way galaxy. It formed around 4.6 billion years ago. The solar system is a group of planets rotating around a central stationary body, called the Sun. The other members of this system include things such as planets, comets, asteroids, meteoroids and moons. There are eight planets that orbit around the Sun including Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus and Neptune.