Why the theory of universe having a center is not true, we would have more suitable and easy way to measure the respective distances between galaxies....if we have a center of universe....we can have a universal frame of reference of motion. then why don't the universe has a centre which may be at rest.......unless the whole universe is moving...w.r.t. to some other universes... Jesmul Hossain
............as you speak Mr , sir, to address your point ''Why the theory of universe having a center is not true, we would have more suitable and easy way to measure the respective distances between galaxies''--------There starts the theory of CHAOS......and Herman Weil as well as with S Subramniam also proposed ''''The Oscillatory Universe'', later it was substituted by the steady state theory [supported by Hawking, Graham Green,[Lucacian Chair , at Cambridge, next to Hawking] Penrose] and abolished by Prof Wheeler[Einsteins Chair , Prinston]........let us exhale on it.......Case 1: The Observable Universe
We are, by definition, at the very center of our observable universe. However, an alien species on a planet one billion light years away from us is at the center of their observable universe, which is very different from ours.
Wherever you go, you will be at the center of your observable universe, because the observable universe is the part of the universe that you can see, and the light from all the stars and galaxies on the edge of the observable universe takes the same time to get to you, no matter which direction it came from.
So you can imagine the observable universe as a sphere (or ball) that is centered on you and follows you wherever you go. However, there is nothing special about you specifically; anyone else in the universe experiences the same thing.
continued.......................Case 2: The Entire Universe
It should be stressed that in contrast to the observable universe, the entire universe - all of it, including the parts that lie far beyond our observable universe - does not have a center.
Here are two very common misconceptions that lead people to believe that the universe has a center. I hope that correcting these misconceptions will make it clearer why the universe does not have a center.
The "Singularity = Single Point" Misconception
It is a common misconception that the universe was originally a single point. It is crucial to correct that misconception.
There is an infinite number of points in space at any given time. As the universe expands, we measure the distances between any two points to be larger than they were before. If we extrapolate this back in time, we find that the distances between any two points shrink.
If we continue this process naively, we eventually find that far enough in the past, the distance between any two points is exactly zero. This is the infamous "singularity" of the big bang.
Now, it's important to understand that in this process, points are not created or destroyed. Only the distances between them change. So even if there really was a singularity (which is a matter of debate), it's incorrect to say that "the universe started as a single point and then expanded".
The correct statement is: "The universe started in a state where the distance between any two points was zero, but there was still an infinite number of points. Then the distance between any two points started to increase."
This means that there is no "special" point where the singularity happened. All of the points in our universe today were once part of the singularity. If no point is special, then no point can be the "center" of the universe.
The source of this misconception is probably the description of the big bang in popular science publications as "an explosion". This seems appropriate, because it's called the big bang, right? Well, the name is unfortunate, but we're stuck with it.
When most people imagine the big bang, they imagine a single point "exploding" and expanding. But wait a minute... Expanding into what? There's nothing "outside" of the universe for the universe to expand "into"..
....and Finally, ........Misunderstanding The "Balloon Analogy"
Another "crime" of popular science is the infamous "balloon analogy". If the expanding universe is like an inflating balloon then the center of the universe is at the center of the balloon, right..?
No! It's common to misunderstand the balloon analogy and imagine that the universe is the entire balloon (including the air inside). This balloon does have a center, obviously, but it is not the appropriate analogy.
Instead, the correct analogy is to imagine that the universe is only the surface of the balloon. You completely ignore the air inside or outside the balloon.
Now mark points on the surface of a deflated balloon and start inflating the balloon. The distance between any two points on the surface of the balloon will increase.
However, the surface of the balloon does not have a center. If you look at a particular point on the surface while the balloon is being inflated, it seems like all other points are moving away from it. Is this point the center? No - since this is also true for any other point! So either all points are the center, or none of them.
The same goes for the expanding universe: the surface of the balloon represents all of space, and points on the surface represent galaxies.---------------co written with Barak Shamshony, Univ of Bairut.
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