If I understand the big bang theory correctly our whole universe was in a hot dense state. And then suddenly, rapid expansion happened where everything expanded outwards presumably from the singularity. We know for a fact that the universe is expaning and has been expanding since it began. So, theoretically if we go backwards in time things were closer together. The more further back we go, the more closer together things were. We should eventually reach a point where everything was one, or where everything was none (depending on how you look at it). This point should be the center of the universe since everything expanded from it. But after doing a bit of research I have discovered that there is no center to the universe. Please explain to me how this is possible.
Thank you!
In: Physics
Here’s a fun way to look at it: the big bang is the center of the universe.
Imagine a 2D flat surface, expanding through a 3D space. A balloon being inflated, basically. What’s the center of that universe? It’s not a place *on* the balloon, it’s a place inside the balloon. But a 2D creature living on the balloon’s surface (an ant, let’s say) can’t see that spot, it’s not part of the 2D surface he inhabits. If you had to describe that spot to him, you’d describe it as the point where his universe began expanding. This makes sense, because the radial (inward/outward) direction is analogous to time for the ant – “outward” from the balloon’s surface is his future, and “inward” is his past.
You can model our 3D universe expanding through time the same way. There’s no spot in the 3D universe we inhabit that we can point to and describe as the center, but you can imagine that from the perspective of a hypothetical 4D viewer, the closest it has to a “center” is the place in spacetime where it began expanding – the big bang.
One of the big problems with astrophysics (and quantum mechanics) communication is that we use analogous terms for concepts that are otherwise ungraspable outside the realm of mathematics. Without understanding reference frames, hell even with, a lot of it is just very, very confusing. We fall back to the math a lot lol.
ELI5 answer:
Your problem is you seem to be visualizing a sheet of graph paper with a big circle drawn on it; as the circle shrinks smaller and smaller, it will eventually be the size of a tiny dot on the sheet of graph paper, and you can measure the coordinates of that dot on the graph paper and call it the “center.” This is not the correct way to visualize the universe.
The universe is not a circle drawn on the sheet of graph paper—it IS the graph paper. What happens if you shrink the entire sheet of graph paper down to a tiny, single point? You can’t measure its coordinates on the graph paper because all of the coordinates have shrunk down with the universe and every coordinate exists in that tiny shrunken-down speck of graph paper.
I heard a science guy say the center of the universe is the Big Bang. As someone on their couch my take away is that if the universe was a balloon the surface would be 3D space and the center is deep in the molten core of the balloon. And as you remove the many layers of the balloon you go further back in time
It is still not fully discovered/observed if there is even such a thing like an end or a border of the phenomenon we call universe.
See also the Illustris Project [Illustris – Media (illustris-project.org)](https://www.illustris-project.org/media/)
And regards to Wolfram for his [The Concept of the Ruliad—Stephen Wolfram Writings](https://writings.stephenwolfram.com/2021/11/the-concept-of-the-ruliad/)
The universe has an infinite amount of “singularity” points And it expanded outward (and is expanding outwards still) from -all- of them. Singualrity, and Big Bang, are both poorly chosen terms, because they lead every to believe theres a center of the universe, and there probably isn’t -the universe is likely infinite.
Imagine you are a 2d person living on the surface of a sphere.
It is boundless but finite.
Where is the center of your 2d universe?
You’ve probably heard that space is expanding. Everything is getting farther away from everything else as time passes. If you rewind time, everything gets closer and closer together. This intuition inspired the idea of the Big Bang.
Well, if you rewind time far enough, everything and everywhere is squished into the exact same spot, the hypothesized singularity. That means that, no matter where you go, you are in a place or touching something that used to be at the position of the singularity.
If the location where the singularity “was” is what you’re thinking of as the “center”, then that center is, well, everywhere. The point in the palm of your hand is as much the center of the universe as the sun is.
a lot of wildly unknown elements about our universe and mental constraints that limits human ability to understand it. But at its simplest form, to know a center of literally anything you have to define the outer dimensions first. You can’t find the edge of the universe so therefore you cannot define any center that could exist.
If we make an assumption that the universe is a giant ball, theoretically, if you were able travel to the “edge” you’d just be expanding the universe else you’d cease to exist. Thus, you’d be constantly shifting the center of the universe or just not live to tell anyone about it.
Imagine an infinitely long rubber band, going infinite in one direction and infinite in the other direction (as far as we can tell). This rubber band has been stretching for as far back as we can see, so like you said, you can imagine a time when it was at its “shortest” and densest. Except even when this rubber band was at its most compressed, it was still infinitely long (as far as we can tell).
It’s like that, except in all three dimensions. Even when space was at its densest, it was still infinite in every direction (as far as we can tell).
Space inflated everywhere all at once. Or another way to imagine it would be to think that everything in space shrunk in place all at once, and we are still shrinking in place, technically making everything farther away from our smaller perspective.
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