# Where is the center of the universe?

1. Jun 21, 2010

### JediSouth

I have a question. I have been watching alot of docs about cosmology and the origin of the universe, and seems that most agree that it began with inflation. I believe this, but what gets me is this. Where is the center of the begining of this inflation? And, if the universe is expanding exponetionly, then how do we know that when we look far out in the sky, that we are looking in the right direction? If everything is moving away from everything else, then there has to be a point at which it all started...which would be the center of creation. Everything would have expanded away from that point.
That makes sense to me. The only thing I am asking is this. If we look in one direction, and supposely what we see, is what is at that vast distance, because of the time it took for that light to get here, would mean we are looking at the begining of existence. But, what if we look in the opposite direction? Of course, things would always be moving away from each other, but what i cant figure out is this. We are lookiing at at those vast distances,and they show the begining of creation, because of the distance it takes for that light to reach us, but how, the begining of creation should only be seen by looking in the direction of the origin of creation, which would mean we would have to be looking towards some center of where it all started. How do we know that we are looking at the begining of time when what are are analising at those millions of light years away is what has traveled AWAY from some center. It's a paradox to me. Why, just because the light we see took billions of years to get here, that that is the begining of time, wouldnt the beging of time only be visible by lookin in the direction of the origin of it? There must be a center right? from which inflation began.
I dont know. I am not a physics prof but I am absolutely fascinated by these things and i understand the conceptual theories, just not the math. That gives me a disadvantage. But it defeinatly intrigues me
If anyone has a theory of this, I'd like to hear it please
thanks

New guy with lots of thoughts...lol

Last edited: Jun 21, 2010
2. Jun 21, 2010

### Staff: Mentor

Welcome to PF. Imagine sitting on a high mountain. Turn around in every direction - in every direction, the earth looks roughly the same. This is a good 2d analogy for the 3d space.

Everywhere we look in space, it looks about the same. This implies rather strongly that there is no center to the universe. And expansion need not require one: replace the Earth with a giant balloon, expanding, and the analogy still holds.

Last edited: Jun 22, 2010
3. Jun 22, 2010

### Chronos

The CMB [cosmic microwave background] intensity is virtually identical in all directions as viewed from earth. This would not be possible unless earth happens to be very near the 'center' of the universe. Given earth is not the center of the solar system, is vastly distant from the center of our galaxy, and not even close to the center of the local group of galaxies, the proposition appears hugely improbable. See, for example, http://www.astro.ucla.edu/~wright/cosmo_01.htm

4. Jun 22, 2010

### IanTBlack

I'm going to have to agree with JediSouth. The implications are strong that there is not really a center of the universe. Imagine you are on a lake and if you look around you don't see any shore. How is it possible to know if you are in the center?

Also, when something is spinning, that doesn't mean that the object is spinning on its center axis. The point where the object is spinning is the spin center, but not the object center. What I'm trying to say is that you can't decipher an objects center through its spin.

Yet if we go with the Big Bang Theory and assume that during the moment when everything was at a single point and then it exploded, that the single point would have been the center of the universe and would still be. Although the expansion of the universe would beg to differ. Some parts probably expand faster than others. Therefore, the universe is more of and amoeba and does not have a center.

Just some thoughts.

5. Jun 22, 2010

### HallsofIvy

This argument is not correct. If every object in the universe got farther away from its nearest neighbot, that would be "expanding"- but there would not be, and there does not have to be a "center" of expansion.

As far as your "amoeba" analogy is concerned, I agree. But you are incorrect that the Big Bang occured at a single point. There was no space before the big bang. It is correct to say, rather, that every point in the current universe was the point where the big bang occured.

6. Jun 22, 2010

### IanTBlack

So what you are saying is that every point is the center?

7. Jun 22, 2010

### Lok

Space does not need to have been created at the big bang, and we will never know. So this concept of every point being a center is a theory.

Just one of many theories that may or may not hold water. All try to explain a few unexplained things about or universe, mainly to this thread is the average matter density of our observable universe which is rather constant anywhere we look, and the accelerated expansion ( with mystical dark matter & energy theories).

8. Jun 22, 2010

### Nickelodeon

I never feel comfortable with the expanding balloon analogy because in this case the centre of the balloon would be the origin of expansion.
Also, the thought occurs that more than likely we are not be able to see the entire universe (Hubble horizon??) and so are not in a position to determine if the receeding acceleration and direction (edit .. of the distant galaxies) points to a preferred area.

9. Jun 22, 2010

### Staff: Mentor

That's a misreading of the analogy: the center of the balloon is not a point on the surface of the balloon.
The other galaxies we see and the CMB provide such a dreference.

10. Jun 22, 2010

### JediSouth

Yeah, but how would that be possible? if every point was a center than that would mean we are in multiverses. maybe like a fabric of some kind resembling the way the physics of atoms work only in a larger scale.

11. Jun 22, 2010

### JediSouth

Exactly!! There would have to be a center of that ballooon.

12. Jun 22, 2010

### Staff: Mentor

No.

Ignoring the meaning of the analogy does not make it go away. You must deal with the analogy as it is actually worded/defined. Otherwise, you're just arguing against a point that doesn't exist.

13. Jun 22, 2010

### CosmicCrunch

idk i i think when people use the balloon analogy there stating that the universe is stretching, not expanding

14. Jun 22, 2010

### IanTBlack

The balloon analogy also makes it seem as if the universe is expanding at roughly the same rate. It isn't. Some parts go faster than others.

15. Jun 23, 2010

### Fredrik

Staff Emeritus
Jedi, Ian, Nick...There must be hundreds of these threads already. If you do a search, you will find hundreds of answers to your questions. Some of them bad, but the ones given by people with science advisor or mentor status are almost always good.

Lok...You have the wrong idea about what a "theory" is. It's not a guess that may or may not be true. A theory is just a set of statements that can be used to make predictions about results of experiments. So it doesn't make much sense to say that something is "just" a theory.

Last edited: Jun 23, 2010
16. Jun 23, 2010

### Chronos

Yes, that is what Halls of Ivy is saying, and I agree.

17. Jun 23, 2010

### Staff: Mentor

Incorrect: it is expanding at the same rate everywhere.

18. Jun 23, 2010

### seto6

think space as a balloon. before "big bang" think if the balloon has no air then blow it up then find the center...you cant find the center. if it has cent it would contradict infinte universe

19. Jun 23, 2010

### IanTBlack

Why is it expanding at the same rate everywhere?

20. Jun 24, 2010

### Lok

Because the overall density of the whole bigbang matter is thinning, and a relativistic view of this means time is accelerating and space is expanding. It is a twofold thing that results in acelerated expansion.