Looking up at a clear night sky, you see stars in every direction. It almost feels as if you’re at the center of the cosmos. But are you? And if not, where is the center of the universe?
By Marcus Woo | SPACE.com
he universe, in fact, has no center. Ever since the Big Bang 13.7 billion years ago, the universe has been expanding. But despite its name, the Big Bang wasn’t an explosion that burst outward from a central point of detonation. The universe started out extremely compact and tiny. Then every point in the universe expanded equally, and that continues today. And so, without any point of origin, the universe has no center. [Big Bang to Civilization: 10 Amazing Origin Events]
One way to think about this is to imagine a two-dimensional ant that lives on the surface of a perfectly spherical balloon. From the ant’s point of view, everywhere on the surface looks the same. There is no center on the sphere’s surface, nor is there an edge.
If you inflate the balloon, the ant will see its two-dimensional universe expand. Draw dots on the surface, and they will move away from one another, just like the galaxies in our real universe do.
For the ant in this two-dimensional universe, any third dimension that extends perpendicular to the balloon’s surface – like traveling into the center of the balloon – has no physical meaning.