General Question

clioi's avatar

Where is the center of the Universe?

Asked by clioi (532 points ) January 28th, 2010

So, the Big Bang happened, and the universe started expanding outwards. If it expanded basically uniformly, then there should be an identifiable center, shouldn’t there? Is that wrong? If it isn’t, then do we know where it is?

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46 Answers

marinelife's avatar

“Now we know that not only are we humans not at the center of the universe, but there is no center of the universe!

The Big Bang is the name scientists give to the events that started the universe. The Big Bang is often described as a huge explosion. But the problem with that picture is that an explosion has a central point where it starts, such as a bomb or a spark. The Big Bang wasn’t like that, but an explosion is the closest thing in our everyday experience to help us understand it.

The Big Bang cannot have happened at a particular place in the universe, because before the Big Bang there was no universe! The Big Bang happened everywhere at once, about 14 billion years ago, bringing space and time into existence. The Big Bang kicked off a rapid expansion of space, and space has been expanding ever since.”


Fyrius's avatar


But still, if the universe is expanding I presume that means it has edges, because something of infinite size can’t become bigger. (Not by our earthly conceptions of what “infinite” and “become bigger” mean anyway.)
If it has edges, doesn’t that mean there’s a centre after all? It would be the point equidistant to all the edges.

Blackberry's avatar

I agree with both answers, it really is unknown though. I believe I read that 4% of space is only the galaxies that we see and the rest is unknown/ an empty sea of black vastness. The center could be in there somewhere lol, not that it matters anyways, you’re not going there.

clioi's avatar

@Fyrius, but how can we tell where the edges are? we’d have to know what is ‘outside’ the universe, if there is anything, to make a distinct measurement.

stump's avatar

These arguments assume an objective universe. The only universe I know exists is the one I experience directly, and that is a subjective universe. And at the center of this subjective universe is me.

mattbrowne's avatar

General relativity teaches us that spacetime is curved. There are no edges. If we had a super fast spacecraft it would move along curved spacetime. We should not picture the universe as a 3-dimentional sphere.

12_func_multi_tool's avatar

It’s every where and no where at the same time. I like Marinelifes’ description of the beggining without a center because there was no place to be center. The Cosmos can be modeled like this: Galaxies are in clusters and random patterns. They are distributed like bubbles in a bubble bath with galaxies concentrated in the edges and intersections of the bubbles and everything is moving away from each other regardless of position.

aphilotus's avatar

The universe is infinitely big, so technically you can place the center of it anywhere, as anywhere you go inside the universe you will be equidistant to all of its edges.

Now where the gravitational center of all of the stuff in the universe is, that is a bit more of an unknown.

Snarp's avatar

@Blackberry Well, a lot of that empty blackness is actually dark matter.

Blackberry's avatar

@Snarp Yeah that’s the term I was looking for.

stranger_in_a_strange_land's avatar

As @mattbrowne said. the universe may be a multidimensional construct, many of these dimensions beyond our current ability to visualize or even indirectly measure. “Center” may only have meaning in 3 or 4 dimensions as our minds can comprehend. Gazing at a Mobius drawing may give you some hint of it.

Snarp's avatar

OK, I’ve got no clue on the real math of this, but if we compare a two dimensional universe to our own three dimensional one, we can see that our three dimensional objects could pass through a two dimensional plane and only be recognized as their two dimensional equivalents. I know that mathematicians theorize a similar effect for higher dimensional objects in three dimensional space. So what I’m wondering is, could the big bang simply have been the entry into our three dimensional space of the multidimensional universe? Does that make any sense at all?

Fyrius's avatar

We can’t, probably. At least not yet. I wouldn’t know how. We can even observe only a small part of the universe.

Should we picture it as the surface of a four-dimensional balloon, then?
If I could take such a visualisation literally, then there’s still a centre, but it’s a point in the emptiness encapsulated by the universe, instead of a point in the universe itself. Also an interesting perspective.

How do you know the universe is infinitely big?

12_func_multi_tool's avatar

somtimes galaxies do collide. the critical density of the universe is one atom per cubic meter(I think, I hope) anymore and the expantion will stop and the big crunch, and less and forever expanding at critical density a static universe.
@stranger_in_a_strange_land Do you know how to describe the dimensional properties of the warp in space caused by a gravitational object?

stranger_in_a_strange_land's avatar

@12_func_multi_tool That goes beyond my math level. I was trained as a mechanical engineer, not a theoretical physicist or cosmologist. Even that math I took over 30 years ago and I’m concentrating on my history doctorate now

Nullo's avatar

As I understand it, any given point of an infinite universe is effectively the center.

Fyrius's avatar

“Do not worry about your problems with mathematics, I assure you mine are far greater.” – Albert Einstein

Theoretical physics seems to take more imagination than math skills, at least at our layman level where we don’t have to verify all the details.

ucme's avatar

In He Man’s tighty whitey’s~

noyesa's avatar

There is no concrete definition of the universe. Many of the theories that are supported by modern cosmology are backed up with evidence largely relying on the cosmological principle—the assumption that the behavior of the universe is the same elsewhere as it is here, meaning we do not occupy a location in the Universe that distorts our view of the rest of it.

Most evidence seems to support that the universe expands faster than the speed of light, meaning we cannot see the entire thing. There is in fact darkness beyond the most distant stars available to our observation. This is essentially an “emerging” portion of the universe—part that already exists, but is only now becoming visible due to the length of time it takes for the light emanating from it to reach earth.

There are models that predict earth’s locality in the universe, generally suggesting we are somewhere near the outer edge. However, because of the limitations of trying to predict the behavior of the universe using light, there is little supporting evidence to prove that what we know about the universe can accurately predict anything. The age is generally believed to be around 13.7 billion years, but these estimates are made using a number of different things—the background microwave radiation (believed to be an energy emission from the big bang), the age of extra-terrestrial materials that have landed on earth. Background radiation gives us the cooling time of the universe, and we can also observe the rate at which the edges of the universe are moving away from us.

However, these observations are based on the belief that things act no differently elsewhere in the universe as they do here, which there is zero conclusive evidence to support. Misunderstood things, such as dark matter, are believed to be faster than light, and is believed to cause the expansion of the universe, so any conclusions anyone can make about the universe is either an assumption, or a very, very rough estimate.

gasman's avatar

The universe has no center. The big bang was not an explosion from some point into pre-existing space. It was space itself that exploded & has expanded from a single point. All observers everywhere in the universe will see everythingelse universe flying away from them.

To use a familiar analogy in a lower dimension, imagine a 2-dimensional universe on the surface of a gigantic, slowly expanding sphere. To creatures on the surface there is no center, yet everything is moving uniformly away from them. Likewise, for the same reason, our 4-dimensional universe has no center.

It is ‘finite but unbounded’.

stump's avatar

@Snarp I don’t know the math either, but that sounds like a very cool idea. It reminds me of the book Flatland, about a triangle explaining his two-dimentional world. He eventually meets a sphere, who looks to him like a circle that keeps expanding and contracting.

12_func_multi_tool's avatar

@stranger_in_a_strange_land thanks, it’s just been on my mind a lot and it bothers me I do not know how better to describe in with technical terms with all the bells and whistles.

Snarp's avatar

@stump Flatland is pretty much everything I know about multiple dimensions. But you can see how it might be possible that there was nothing in the three (or even 4) dimensional slice of the universe, and now a higher-dimensional figure is passing through that slice, and appears to be expanding from all points. Surely some physicist type has addressed this idea.

12_func_multi_tool's avatar

@clioi the things is there is nothing to expand into. at the theortical edge of the universe everything stops, physics, time all those things. Things are not expanding space itself is elongating.
A little rough jewel I just love: can space exists without matter to define it.
Or how can space exist if we have go points of reference to take the meter stick and measure the distance.
-Goethe To think as on should is easy, to act as one thinks is hard.

mattbrowne's avatar

@Fyrius – Well, the balloon model is good for visualizing the effect of dark energy. The dark spots on an inflated balloon represent galactic superclusters (gravity wins). Blowing more air into the balloon shows us how these islands of matter are all receding from each other. Spacetime expands faster than the speed of light (matter as such can’t do this). Many models tell us it’s at least 90 billion light years in “diameter”. Which might sound strange because of the age of only 13.7 billion years. In the distant future there won’t be any Hubble deep fields for our astronomers to observe.

CyanoticWasp's avatar

It’s two inches behind my eyes, if it’s anywhere. Two inches behind yours, too.

SeventhSense's avatar

In my apartment…as for the Big Bang…OH!! that’s what she said

Qingu's avatar

Stephen Hawking says that it is a mistake to think of the universe as having “edges.”

It is finite, but boundless—like the surface of the earth. You can walk around the surface of the earth and never fall off. There is also no central point to the surface of the earth (note: the curved 2-Dsurface, not the sphere.)

There is a “northernmost point” to the surface of the earth. This roughly would correspond to the big bang being the “earliest point” in the universe. But the north pole isn’t an edge or a boundary. It’s just another point.

noyesa's avatar

@Qingu There is still a finite center to the earth. We live on the earth’s surface, not within its volume. From the perspective of any point within the earth, there are finite “edges” of the earth, even if that isn’t the most semantically appropriate term—there are finite boundaries.

Qingu's avatar

@noyesa, what center and what edges to the 2-D surface of a sphere are you referring to?

What you said seems to make not a lick of sense.

SeventhSense's avatar

Your statement only makes sense if you are taking into context the entire volume of the earth which would make the central point its core. .

HTDC's avatar

I don’t think the balloon analogy really works in relation to our universe. I mean, we live in the universe, not on it. I just don’t think it’s that simple, comparing our expanding universe to the expanding dots on a 2 dimensional surface. I don’t know, that’s just me.

Snarp's avatar

I think that the balloon analogy is just to make up for the fact that we are three dimensional creatures, and have extreme difficulty grasping more dimensions. A balloon is to a 2 dimensional creature as the universe is to a 3 dimensional creature.

Qingu's avatar

@HTDC, I’m not sure if there’s a better analogy.

The universe is curved sort of like how a 2-D manifold can curve in space. It’s just important to remember that, unlike a 2-D surface in 3-D, the “surface” of the Universe is all there is. Or at least, most of our physical concepts, like time, space, and existence, simply make no sense “outside” the universe (in fact there is no such thing as “outside” the universe in the first place since “outside” is a concept having to do with space.)

CMaz's avatar

“Where is the center of the Universe?”

Right where I am standing.

HTDC's avatar

Just thought I’d put up a link to show an animation of the balloon analogy. It makes sense.

It’s the second image on the page.

gasman's avatar

Not only is there no center, there are no edges either. Again, if you’re a bug on a giant sphere you can go forever & never hit an edge—though it’s conceivable (depending on geometry) you might return to your starting point.

Space is curved in the 4th dimension. Isaac Newton presented us with absolute space & time, like a stage upon which the universe plays out. Einstein forever dispelled that notion. Get over it!

HTDC's avatar

Edit: Never mind.

12_func_multi_tool's avatar

@gasman so the dip caused by gravity is in the forth dimensional realm? I’ve always compared it to placing a paperweight in the middle of a bed with taut sheets. That is far as my insight goes.

LostInParadise's avatar

You might be interested in this book: Shape of Space I had a trouble getting past the first few chapters, but he does a good job of making the point that the Universe could be constructed like the surface of a 4 dimensional space, but there is no need for there to be an actual underlying four dimensional space.

hiphiphopflipflapflop's avatar

The Big Bang did not happen in a preexisting space. Space along with everything else is what “banged”. Every point in space was coincident at the moment of the Big Bang, so every point in space has equal claim to being at the center of the universe.

MrsDufresne's avatar

In my opinion, it resides in the amygdala.

gasman's avatar

@12_func_multi_tool Yes, the ‘rubber sheet’ analogy is a good one—dimples in the surface show the curvature of an otherwise flat Euclidean plane. What you’re seeing is a 2-dimensional space warping in the 3rd dimension. Likewise we have to imagine a 3D rubber space warping into the 4th dimension, which no one can visualize or grasp spatially. Fortunately the equations themselves are clear & readily solved in 4 dimensions.

A flat sheet of uniform elasticity, such as the Latex bedsheets they used to sell (now usually attached to non-stretchy fabric), actually makes a pretty good analog model (with analogous mathematical behavior) of concentrated mass distorting Euclidean space. This is a local effect. For large-scale cosmic structure, however, the rubber sheet analogy fails because it assumes overall flatness, which is apparently not the case for our universe.

Self_Consuming_Cannibal's avatar

It’s somewhere in the middle. lol

krrazypassions's avatar

Theorem: ”Either there is no center or every point is a center

See, at first there was nothing. 0

Then, came a singularity. 1. The center. (You can of course assume that there was no center and that would be the end of the discussion-
No need to read further if you have chosen the no center choice)

Then everything started expanding. Everything was moving away from the center. Today, when we observe any far-away galaxies, everything is moving away from us(except for the things in our galaxy and the Andromeda galaxy, which is heading straight at us and will collide one day). Hence, each of us are the center. Similarly, for the aliens in the Andromeda, they will be the center.

Hence Proved

ps: for those who have not yet grasped the implication of this theorem,
There is no center

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