How can the universe not have a center? #BigBangTheory #CenterOfUniverse #Expansion
Have you ever wondered about the center of the universe? According to the big bang theory, our universe started from a hot, dense state and rapidly expanded outward from a singularity. But despite this expansion, there seems to be no center to the universe. How is this possible?
Understanding the Big Bang Theory
Explanation
– The universe began in a hot, dense state
– Rapid expansion occurred, leading to the universe we see today
– Everything was closer together in the past
– The idea of a singular point where everything came from
– Rapid expansion occurred, leading to the universe we see today
– Everything was closer together in the past
– The idea of a singular point where everything came from
The Mystery of the Universe’s Center
No Center?
– Research shows there is no definitive center to the universe
– Despite expansion, there is no point where everything originated
– Despite expansion, there is no point where everything originated
Exploring the Universe’s Origins
Theories
– Alternative viewpoints on the formation and expansion of the universe
– Concepts of a singular point versus no center at all
– Concepts of a singular point versus no center at all
Clarification and Conclusion
Final Thoughts
– Understanding the complexities of the universe’s origins
– Exploring different perspectives on the concept of a center
– Exploring different perspectives on the concept of a center
Thank you for sharing in this fascinating exploration of the universe’s mysteries! #SpaceMysteries #CosmologyExplained
As you say the centre of the universe was where it started and expanded from. All points of the universe fit this description so everywhere is the centre or alternatively nowhere is.
You are correct your thought process but you run into the “trap” a lot of people run into. You imagine the big bang as a single point where everything started like a bomb. This isnt true, the big bang happend everywhere, everywhere was just much closer together and thus matter was also much denser but the universe still was infinite. This is confusing because most people think that something that is infinite cant become bigger but it can.
To explain that it is much easier to go one dimension down and explain it in 2D.
Think about a 2D area like the surface of a balloon.
If we blow up the balloon the surface expanses.
Is there any point on this surface that could be called the center?
No from each point all other points move away if we blow up the balloon more.
Same we see with telescopes looking into the deep space.
Picture a super-stretchy rubber sheet that goes on and on in all directions forever – an infinite rubber sheet. There’s no center to the sheet – it’s infinitely large. Now imagine there are tiny dots everywhere on the sheet as close together as is possible to place such dots, really squeezed together so that you really can’t tell where one dot ends and another dot begins (but they are separate dots nonetheless). And now image that the sheet is stretched evenly right and left and forward and backward, it just keeps getting stretched and stretched and stretched. As it’s getting stretched, it doesn’t get any larger (it was infinite to begin with), but the dots are all getting stretched further and further apart. So the sheet is expanding, and everything on it is getting further and further away from everything else on the sheet, but there is no center of expansion – it’s expanding everywhere all at once. Bump that up to three dimensions and picture an infinite (and infinitely stretchy) block with dots crammed in everywhere. Stretch that up and down, right and left and forward and back. All the dots move away from all the other dots, yet there is no center. The expansion looks the same no matter where you are in that block.
The thing is you have to look at space as something that can expand and contract. Theoretically, the big bang is a point where all space essentially expanded from. So, no matter what direction you travel in along the X/Y/Z axis, wherever you are will contract to that same initial point if you move backwards in time.
Once you have this one single point of the big bang, moving along the X/Y/Z axis doesn’t really make sense. If that one single point is the origin of the whole of the universe, moving away from it is travelling *outside* the universe.
So. No center. It would have a center if you presume the universe is not infinite, and space already existed outside the big bang *before* the big bang.
The big bang was not an explosion of stuff moving out into space, it was an explosion of space itself carrying the stuff with it. Galaxies and galaxy clusters are gravitationally bound to each other, but every galaxy cluster is moving away from every other cluster.
If you blow up a balloon, every point on the surface of the balloon is moving away from every other point. A two dimensional person on the surface of the balloon would not be able to point to the center of the expansion, they would only know that *everything* is expanding. This is only an analogy, we don’t know if there are other spatial dimensions that we can’t comprehend, but it works well for getting the idea across.
Some scientists believe that the universe is finite, but still does not have any “edges”, because of its geometry. If you “freeze” the universe to stop it from expanding, and then keep going in one direction for a very very long period of time, sooner or later you will end up in the same place where you started.
Imagine you have a one-dimensional movement freedom within a two-dimensional object (circle on a piece of paper). If you keep moving along the circle, you will end up at some point where you started. Now, imagine a two-dimensional movement across a three-dimensional object (moving on a surface of a sphere). If you keep moving in any direction, as long as it’s being constant, you will again end up in the same direction. The same goes for the universe, but You need to think of one additional dimension to put into the equation.
Now, let’s get back to the example of moving on a sphere. Assume the sphere keeps getting bigger and bigger (simulating the universe expanding). Regardless of the place you start from, all points of the sphere’s surface keep getting further and further from each other, which makes it seem like the place You started from is the center of the sphere’s surface. However, if you pick another spot on that surface, the same will be true.
The same principle applies to the universe, but instead of it being a two-dimensional surface, it’s a three-dimensional space.
If someone is able to explain it better, please do. I keep trying to wrap my head around this concept and am constantly looking for other ways to approach this.
You are thinking of the universe as an object like a balloon that was once small and then it blew on it so it expanded, displacing the outside but still having an inside. The universe is not like that, or at the very least we can’t define anything like. We don’t look at some point of the sky and see en edge that is concrete, then look in the opposite direction and see another edge, then calculate the midpoint between the two.
It might sound intuitive I know, but the universe simply doesn’t work like that.
For one, everywhere we look at it there seems have the same distribution of stuff, yeah some points might have a bit more or a bit less, but in the whole the universe is isotropic. The Big Bang happened everywhere, and though things are getting farther apart it’s not the same as someone blowing more air inside a balloon. The universe itself is just fundamentally a different structure than day to day objects.
We also don’t observe any curvature in the universe. It’s flat, as in, two parallel lines will remain parallel, and not converge (bump on each other) nor diverge (go their separate ways), something you’d not expect from a 3D structure like the universe, you’d expect things to be more non-Euclidean, like the earth, where too parallel lines will end up converging.
So, the universe has some properties that make it appear like an infinite thing, which can’t have a centre.
Because the universe is not a 3d Model. imagine it this way, you have a seemingly infinite balloon. Now you exist within that balloon , which keeps expanding in every direction rapidly, you dont know where you are within that balloon, and you are asking where the point is where it started inflating ?
think of a spong un-squishing equally after being squished. there was no 1 singularity, which is the only wrong thing in your post. all parts of space just started expanding together.
There’s a few fundamental traps that are hard to intuitively grasp about the big bang as a “starting point”.
1 – the big bang is everything, everywhere. It didn’t “happen and then now we’re after that”, we are currently experiencing it, the expansion of space is still happening, and that’s our primary evidence for its occurrence. “the big bang” describes the entirety of the *present* existence of the universe, not an event that kicked it off.
2 – The big bang is the start of *space* existing as we know it. Not just matter. This can be hard to intuit because we think of it as “all the matter was closer together in empty space, then moved away from each other, occupying different space”, which is only kind of true. But the big bang describes *space itself* expanding, meaning the objects didn’t necessarily “move into other space” (there wasn’t space to move into), but in many cases could be thought of as the *space between objects growing*, while the objects didn’t really move. This one is really hard to explain, and even harder to understand because it’s just entirely unintuitive and runs contrary to our thinking about every day scale and the movement of objects.
3 – In many current models of understanding, “spacetime” is one thing, and includes space and time dimensions. This is how relativity is modeled, why things “experience time differently” in gravity wells or at high speeds etc etc. What this *means*, is that the big bang is the starting point for *time* as well as matter and space. Effectively, as you “travel back toward the big bang”, and the universe gets more dense… the time distance to the “beginning” also increases. Time is weird and hard to really grasp (and hard to model), but ultimately what this means is that getting to “time = 0” at the big bang would take infinite amounts of time. I find it helpful to think of it like a mathematical graphic asymptote, where reaching T=0 is impossible, and things get infinite and unintuitive the closer you get.
The way I interpret it (and I’m in no way an expert), to determine the “center” of something you have to know where the edges/limits are. As far as we know, the universe is infinite and has no limits. Thus impossible to triangulate a center.
Regarding your second point about going back in time to the Big Bang, space & time (as we understand them) didn’t exist before the Big Bang. So it’s impossible to point to the center of something that doesn’t exist
It’s not that things are expanding into previously empty space. The space itself is expanding. Where did the Big Bang occur? Literally everywhere.
The universe is a hyper-sphere and therefore has no center. If the universe had a center and was of a limited size we would have notice it. We haven’t.
It might have a center. We don’t know because we don’t know if the universe has boundaries. If it’s infinte in all directions, then there cannot be said to be a center (infinity divided by 2 is still infinity). We can’t even say that it doesn’t fold back on itself (kind of like the game Asteroids where the asteroids and ships go off one edge of the screen and appear on the opposite edge). So, we don’t claim that there’s a center but accept it as an open question.
We do know that there’s a practical limit how far we can see into the universe. Light only reaches us so fast. So, from our perspective, we sit somewhere in the universe and we can look into space and see stuff up to a certain distance away. The part we can see is a sphere extending out 46.5 billion light-years in every direction from us, and we call that the “observable universe”. We’re at the center of that, obviously.
I’ll go about this from two perspectives. Remember that The Big Bang is actually not a single theory, there are many versions. And even theories without it. I’ll just explain some of the most common concepts according to these theories.
First of all, you need to accept a very abstract concept about how the universe functions. Space *itself* expands. Imagine a balloon where you draw a bunch of dots on, representing stars. Now blow up the balloon. Suddenly, there is much more room between all stars. The space between them increased.
Now, this is not to be confused with “the stars just moved”. The thing is, you have dots all around this balloon, so there is no way in which they could move away from each other without getting closer to other stars. But by literally making space itself bigger, now they can all get further away from each other.
It’s like a house where the square meters constantly increases. Furniture keeps getting further from each other.
This is the expansion of the universe. Now, imagine this backwards. The balloon deflate, making space smaller. This might seem *very* weird when we also say space is infinite, but that is just too abstract to visualise. Just accept for now that all of space itself ends up at a single point, along with all matter of the universe.
Now big bang happens, but all of *space* itself was at this origin “center”. So every point in our current space used to be at the center.
This gives you a pretty wild phenomenon, because it isn’t that the universe lacks a center, it’s that **everywhere is the center*****.*** This is quite fun, because when people say “Earth isn’t the center of the universe”, they are wrong. It *is* the center, but it’s just not that special when you remember everywhere else is also the center.
The second perspective is about the fact that the universe is infinite and homogeneous. Infinite, as you likely already know, means it continues in every direction forever. Homogeneous means no matter where you are, there is an equal amount of everything (like stars, planets, galaxies etc.). Note that yes, even if something is infinite, it can continue to expand. There are different sizes of infinite (don’t try to visualise this, again – just accept it. This is beyond the question).
Now, why do I bring up this? Well, because it challenges the idea of a single center. If the big bang happened at a specific center in space, then all matter in the universe must have originated form there. But then how can there be equal amount of matter everywhere? Only a finite time have gone since the big bang, so if it was a single place in space, then matter can’t have reached all corners of an infinite universe yet.
So with that in mind, the big bang *have* to have happened everywhere all at once, because only this way can there be equal amount of matter everywhere.
The thing is, you’re envisioning the universe expanding into existing space. If that was correct you’d be right, there would be a center.
But that’s not what happened, and is continuing to happen.
The universe started as a singularity that contained all of space too. There is no space outside the universe.
When the universe expanded in the big bang it wasn’t like an explosion expanding into space. It was space itself growing from that singularity. All points in the universe were, once, that singularity.
If this is hard to wrap your mind around, that’s because it’s a concept we didn’t evolve to easily understand. Or to understand at all. To us the very concept of nothing is more or less impossible to really grasp. To us the idea of all space existing in a single point, of all space expanding (not into some place because there is no other place) is really damn hard to truly understnad. I don’t claim to, I’m just repeating what I know from scientists and I’m taking their math more or less on faith since I can’t personally follow it.
It doesn’t help that space is infinite and there’s no edge to the universe.
One possible way to imagine it might be to put it in two dimensions.
Imagine you have a torus of infinitely stretchable rubber. It starts quite small, but you stretch it from the inside.
There is no center from the standpoint of a 2d being living on the interior surface of the torus. Travel from any point on the torus and you’ll eventually wind up back where you started from. No center, no edge. If it expands it’s not expanding into some place already extant in the torus, it’s growing the extant space.
From our 3d standpoint, you can argue there is a center: the midpoint in the torus in 3d space. But to a 2d being living on the interior surface of the torus that’s not something they can see or even really think about easily. And worse, notice that the center of their universe is, in fact, outside their universe? To them all existence is the interior surface of the torus, therefore the center of their universe is outside the universe…
And possibly from an 11d or 16d or 5d or whatever standpoint our universe does have a center but if it does it would be a point OUTSIDE our universe in a direction we can’t even comprehend on any level except the most abstract mathematical level.
Note, it’s possible that our universe is truly infinite not merely looped around on itself through an extra set of dimensions we don’t percieve. We don’t know. But thinking of it that way is at least a way to sort of, kind of, vaguely, grope towards the basic idea even if it’s wrong in every single particular.
The way I think about it is when the universe expands it expands all places at once
It sort of like the baloon, not the space inside but the actual rubber, imagine this rubber was all one point then it expanded all places at once sort of like a balloon (but again try to ignore the “space” inside)
You cannot really point to a center , or all points were once the center
A center requires a boundary. There is no boundary that we can interpret.
Example: Think of how you live on the surface of earth. Earth is a sphere so it’s ‘center’ as we understand it is in a dimension we can’t really see from where we are. However, in practice, we mostly live on a 2D plane that stretches out in all directions with no ‘end’. If it doesn’t go forever, then you just come back to the same spot eventually. You can travel roughly in any direction along the plane indefinitely.
The universe is like that, but in an a 4th dimension that your brain is simply not capable of understanding intuitively. We’d have to move tangentially through a 4th plane (like time) to find ‘a center’ to the universe.
So, there is no center in 3D space, because there is no boundary in 3D space. You should be able to travel in a straight line in all directions indefinitely.
Imagine a sphere that started as a dot. You’re standing on the sphere. What’s the “center” of the surface? There isn’t one. Also, the sphere keeps expanding.
I might be incorrect and people with better knowledge can explain to me in that case.
Question is incorrect because you are trying to make sense of 10 dimensions with logistics from 3 dimensional perception. It is same as people asking “What was before Big Bang?”. It’s like asking previously blind people what they saw before they got new eye or asking you what was it like before you existed. Time and Space didn’t exist before Big Bang, so there was no center.
May be there is no such thing like starting and ending of existence. May be we are applying our logic of enclosed and limited perception to make conclusion which may not apply in higher dimensions.
Now that the universe has expanded, its like asking where the “center” of the SURFACE of earth is. is it the north pole? The south? Somewhere on the equator? No, you can keep going in one direction and come all the way back around but did you ever pass thru a center point? no.
The universe has a temporal center which is the start , the universe is 4th dimensional , 3 spatial dimensions and 1 of time .
Let’s scale this down.
Take a perfect circle, point to the center, easy.
But where would you say the EXACT center of New Zealand is? Is it even possible for something of that shape to have a center? We can theorize on where that point may be. Math can help, but it’s hard to know for sure.
Now scale that up to an ever expanding object that we can’t even visually see the full scale of. Again, math can help, but it’s difficult to know for sure. And from HOW we observe, we’re looking out from the central point of a location, but that doesn’t necessarily mean the object we’re observing is a circle, square, triangle, rhombus etc. Yet we already know that we’re looking from a point that isn’t dead middle of the shape.
The only way I can wrap my mind around it is to think of it is that we are inside the universe and that we have the laws of physics that apply to the “inside” of the universe, so to us, there is no center due to continuing expansion. If we could look at it from the outside, we might be able to figure out a center, but not while inside.
The “Big Bang” turns out to be a terrible name. It makes people think of explosions and explosions have a center where everything is moving away from it. That’s not what happened.
If you could “see” the universe far enough back in time it wouldn’t be a single point like some people (most?) imagine. It would be like an insanely dense fog of matter made up of subatomic quarks and gluons called (shockingly enough) quark gluon plasma. This plasma would be more dense than anything that we can currently observe in the universe. Just incredibly incredibly dense. And it would be everywhere. You couldn’t actually exist at this point in time, you couldn’t see even if you could, you couldn’t move either, but in our thought experiment if you could move you’d just find this incredibly dense plasma soup all around you.
When the “Big Bang” occurred what happened was that space everywhere all at once started expanding.
Imagine you are standing in the middle a room, perfectly cube shaped. Each wall, the ceiling, the floors etc is a different color. One of the walls is transparent. Another room identical in size to yours is on the other side of that wall. Your friend is standing in the middle of it. Suddenly you both start shrinking and in an instance you are each 1/10 of your previous size. Relative to each other the distance between you appears to have increased by 10x. After all neither of you physical moved. You didn’t go running in one direction and your friend another.
Ok now what if I told you that instead of shrinking what actually happened is the room you were in grew. And so did the room your friend was in. The effect would look the exact same. The end result would be the same. You’d now have to travel 10x as far to reach your friend. Now imagine an infinite set of rooms in every direction just like yours. Each one with a person in it, each one growing at the same rate. It would look no different than if you all started shrinking at the same time. The number of rooms are infinite so they aren’t expanding into each others space it’s the space itself that is expanding. And it’s expanding everywhere in every direction all at once.
You could pick any room and things would appear more or less the same. The further away a person was from you in the starting room the faster they would seem to be moving away from you as the rooms expanded (or you shrank). And if they looked at you it would appear you were the one moving away. But neither of you moved, nor did anyone else. Again it’s just that the distance between you got smaller.
You don’t need a center for this kind of expansion.
So why did space start expanding? We don’t know.
And what was it like BEFORE it started expanding? We also don’t know.
Our current models can’t predict what happened before the Big Bang. Our instruments can’t detect anything that appears to have occurred before the Big Bang. We may never know or understand what it was or why it happened. Scientists and mathematicians will certainly keep looking for explanations and evidence but for now we just have to understand that so far as we can tell the universe doesn’t have any kind of center and it doesn’t even need one.
One of the most common ways to describe the universe is the balloon analogy.
Whereby it is depicted that all of the galaxies and stars and matter that make up the universe are on the outside of an ever-expanding balloon.
The common misconception though is that the interior of the balloon represents the volume of the universe and this is not the case.
The surface of the balloon essentially being a 2D service represents 3D space. The ever expanding air volume inside the balloon can represent the fourth dimension of time. So you’re depicting a four dimensional construct with a three-dimensional object.
Tldr; The surface of the balloon is the three dimensional universe and the air volume inside is the fourth dimension of time. The surface of the balloon has no center and if you were an observer on the surface of the balloon every spot on it would look like the center from every other observable point.
Where is center of surface of ball?