Where is the centre of the universe?

The idea that the universe has a centre has to do with the notion of the Big Bang being an explosion that originated in one point of an already existing void. However, there is no centre, as before the Big Bang, there was no space. Many astronomers describe the Big Bang as an event that took place in all places at a time.

The universe can be described as the surface of a spotted balloon that is inflated. The galaxies are spots on the surface of the balloon. As the balloon grows bigger, the spots move further apart. However, the expansion of the balloon does not originate on the surface, rather in the void inside the balloon – outside the known universe.

The universe is compared to the surface of a spotted, inflating balloon. The expansion does not come from the balloon’s surface, i.e. it takes place outside the universe.