Key Takeaways About the Center of the Universe
- Where is the center of the Universe? In 1929, Edwin Hubble concluded that it did not exist as space continued to expand.
- Gravity can create a “center”, but since gravity acts equally on all objects in the Universe, galaxies, planets and stars are distributed evenly.
- The center of the Universe cannot be anywhere and everywhere at the same time, because the Universe looks the same from all points of view. No matter where you are in the Universe, the rest of space is moving away from you, suggesting that at some point you were at the center of the Universe.
Despite what you may have heard, the center of the universe is not located in Times Square or any other street. French Station, or Wallace, Idaho. But this is not an attempt to find out the cosmic significance of one's most cherished coordinates – the center of the Universe is not located somewhere else either.
It seems impossible. According to NASA, we know that the universe began with the Big Bang 13.8 billion years ago and has been expanding ever since. So somewhere in the very heart of all existence there must be a place where it began: the center. But this is a misunderstanding.
Although we tend to think of the Big Bang as a classic explosion—starting from a single point, like a hand grenade, and then exploding outward in a spherical shape—it is completely unlike any familiar example we would like to give. It was a cosmic explosion, not an explosion in space; normal rules do not apply.
Jeanne Levine, a cosmologist at Barnard College, Columbia University, suggests thinking of the universe as a bubble instead. It's important to note that unlike real bubbles, this one has no interior or exterior – forget everything but the surface, and consider that you can wander around this frothy realm for an eternity without finding a vantage point.
“Everywhere I go, the bubble looks the same as every other place,” Levine says. “No point claims to be the center.”
Read more: The universe began as a “hot soup of particles and photons” 13.8 billion years ago.
Where is the center of the Universe?
The first hint of this strange finding came in 1929, when American astronomer Edwin Hubble discovered that every galaxy beyond ours was rapidly moving away from Earth, with the farthest ones receding the fastest, according to a paper published in the journal Astronomy. At first glance, it may seem that by some extraordinary coincidence our humble planet is actually located at the center of the Universe.
But there is another explanation, better supported by observational data and predictions of the theory of relativity: Universe looks the same from all points of view because spacetime itself expands uniformly everywhere, according to Britannica. This means that there is nothing special about our vantage point; Alien astronomers a billion light years away would see the Milky Way and all other galaxies moving away from their galaxy.
This is exactly what happens with a soap bubble. Imagine its surface covered with dots representing galaxies – as the bubble grows, the dots move further apart as the space between them expands. The universe is, of course, three-dimensional, and not two-dimensional like the surface of a bubble. However, it behaves in exactly the same way, expanding everywhere at every moment, without having anything that can be called a center.
Gravity creates centers – why not here?
You may have another nagging intuition based on easier-to-understand principles of classical physics. Four centuries ago, Isaac Newton demonstrated why the Earth is round, why planets revolve around stars, and why solar systems revolve around galaxies – in short, gravity. Every other unit of astronomy has a gravitational center to which all nearby matter is attracted, giving us the cosmic idea of centrality. Why doesn't the Universe do this?
Each galaxy does exert a gravitational influence on all the others, but no one galaxy wins this titanic tug of war. The thrust is the same in all directions. As a result, the Universe remains remarkably smooth on the largest scales, with matter distributed more or less evenly throughout it. This homogeneity leads to a different result than we see at the levels of planets, solar systems and galaxies. “If I put this into Einstein’s equations,” Levine explains, “they’ll say there’s no center.”
Rewind the Universe
Now let's relax the ban on the inside of the bubble. If we rethink this interior not as space, but as time, we can reproduce the inflation process in reverse. As the bubble contracts, we can see the space in between become smaller and the dots get closer until all the dots converge. This is the beginning, the moment before Big bang. There, one might say, we have a center – it is destined to disappear as soon as expansion begins, but for now it exists, and the entire Universe is contained in it.
So let's get back to the question. Where is the center of the Universe? It turns out there are two meaningful answers: nowhere and everywhere at the same time. That is, not a single point is now exceptional, but every point once was. Even in the cosmogonic embryo, everything that exists today – Times Square, Idaho, your living room – was an integral part of the absolute. In some ways this is still true.
Read more: Did our Universe consume the children's universes, causing dark energy?
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