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
This is a tough one for most people to wrap their head around. Difficult to visualize or understand. But it is true—there isn’t a central point to the universe. The Big Bang banged everywhere, all at once in a tiny universe. What’s even worse, people think empty space was there for it to expand into. Nope! Even space is a part of the universe! So what is the universe expanding into? What was/is there? We don’t know. Sorry!
Imagine a number line like the ones pinned to the wall in 1st grade.
Let’s pick “center”. Zero seems like a natural place.
No let’s imagine that number line extends infinitely in both directions. Starting from zero, going right, we have 1, 2, 3, and so on. Going left from our “center”, we have -1, -2, -3…
With this in mind, our “center point” of zero becomes arbitrary. We can pick any number, anywhere on the line, and when we look left, infinite numbers. When we look right, also, infinite numbers. No matter what location we chose to examine the number line from, we still find that we have the same amount of line in either direction.
Space works in a similar fashion, except instead of just looking at it as an x-axis number line, we have a Y and Z axis to account for. Even so, the rules don’t change.
We can add time, which is nothing more than another axis, perpendicular to our x,y, and z.
To help this relate to the Big Bang, at one point, there’s was absolutely no space between our numbers. There was still an infinite amount of them, but they were all touching. We can go in and add a millimeter between each number, then centimeter, inch, foot, yard, mile, light year.
The addition of that space between the numbers is our big bang, but it doesn’t change anything regarding our earlier attempts at finding the center.
Because having a center assumes that there was space there before the Big Bang. But space was created with the Big Bang, not before it.
Also, when we look at objects and determine their centers, we are looking at them from the outside. We put them in space that already exists outside of the object. We can’t do that with the universe because space (spatial distance) is the object here. There’s no space outside of space. You can’t travel to the edge of the universe and step outside of it and look back towards the center, because you exist in space and wherever you go, you have brought it with you. In that sense, there’s no boundary, because there’s nothing on the other side. And if something has no boundary, how can it have a center?
Imagine our universe is a piece of paper in a book. When the book gets closed, the paper of our universe touches all the paper of another universe, and the big bang occurs across the entire page at the same time. It doesn’t start at the center. Instead, it starts on the entire page.
I genuinely thought this post was going to describe the theme song in perfect, microscopic, thesis level detail
If the universe is infinite the centre would be you from your perspective, right?
I postulate that I am, in fact, the center of the universe. When I look around, I see everything moving away from me, ergo I am at the center. I say it tongue in cheek, but for anything that expands from a point (something with zero length, width, or height) all places within the expanding volume are effectively the center.
The center of something is when there is the same distance to the edges in any direction.
First there is the problem of finding the center. We can’t see the edges, so how can that be done?
Then there is the problem of *defining* the edges. What does the end of space mean? We don’t know.
You’re imagining a single spot exploding, and that explosion expanding into space. That’s not how it happened. Instead, space itself was that single spot. And then space itself expanded.
To ELI5-ify it a bit more, the center of the universe stretched out to become the universe. So everywhere is the center.
The universe is expanding and ELI5 is to bring it down a dimension.
Imagine an extremely tiny ball that is squished into a point. Everything in this 2D universe is squished into this tiny space.
The ball starts inflating like a balloon. The ball expands and expands and eventually 2D ants that evolve on the ball. The ants can walk on the ball that is now enormous, and they ask “where is the center of our universe?” and the answer is nowhere and everywhere.
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