Our understanding of the universe has evolved as technology advances and we learn more about how it "works". For a really long time, people thought that our planet Earth was at the centre of the universe and all the other planets, the sun and the moon revolve around it. However since Galileo Galilei started collecting evidence about the universe using his telescope, around 1609, we have learned that this belief was incorrect. This discovery led to Copernicus' model of the solar system that has the sun as it's centre.