Center of the Universe

Center of the Universe


There is no center for Universe, as every galaxy is expanding away from one another.


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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?

The 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.

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.

"It knows it can go forward and backward. It can go left and right," said Barbara Ryden, an astrophysicist at The Ohio State University. "But it has no concept of up and down."

Our universe is a 3D version of the ant's 2D balloon universe. But the balloon analogy, with its limited surface area, represents a finite universe — which cosmologists still aren't sure is true of our own, Ryden said. Limited by how far light has traveled since the Big Bang, cosmologists' observations offer only a finite glimpse of the cosmos, but the entire universe could be infinite.

If that's the case, then you can replace the balloon with a flat, expanding rubber sheet that extends forever. Or if you want to think of a 3D universe, imagine an infinite loaf of raisin bread that's continuously expanding. The raisins, in this case, represent the galaxies flying away from one another. "If the universe is infinite," Ryden told Live Science, "there is no center."


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