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Rick Ryan


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Why does the Universe look the same in all directions we look, considering an expanding Universe created by the Big Bang?

I've struggled to comprehend this. Looking away from the Earth, we are looking back into the history of the Universe's expansion since the Big Bang. Astronomers report that in any direction we look, at the farthest "distance and time" we can currently see, it appears there is a consistancy in what we see. Galaxies appear to be in the same "time state" of development, etc. If I carry this reasoning out to it's conclusion to where I can eventually see the edge of the Universe in all directions I look (assuming a finite Universe with a boundary), wouldn't that imply the Earth was actually at the center of the Universe? If the light coming back to me showing me the past is representing that in every direction I look I will see the same (time-wise) early state of the objects in the Universe, wouldn't I have to be in the center of it? If I wasn't centered, I should be seeing different "time states" of objects in the Universe depending on the direction I looked after the Big Bang expansion started.

I'm NOT asking this in a religious context. I'm NOT implying the Earth is actually in the center of our Universe to try to support any belief or faith. I'm looking for a theoretical physics explanation that will allow me to comprehend the observation without the Earth being centered in the Universe.

I just can't grasp the concept that if the Earth was a result of the Big Bang expansion, why does it LOOK like I'm in the center instead of off to the side closer to one edge of the Universe than the other? The probability of the Earth actually ending up in the center would be astronomical.


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    Sep 19 2012: You think you look like the center of everything because you can look out in all directions from that place you call you. But no matter what "corner" of the universe you happened to be in, the outlook would be the same. Everything has had about 13.7 billion years to "spread out" away from you, but the weird thing is that that would be true no matter what your starting point was. We all (all the galaxies) had the same starting point. But there are other tricks of perspective that the universe is playing with us: If we tried to go in a straight line, just like light through "empty" space, we would end up right where we started. So much for edges of the universe.

    By the way, don't worry. NOBODY understands this in a way that makes sense with our slower-than-light-speed way of seeing things as human beings. So when you wonder and puzzle over these questions, you are among good company (present and past).

    • Sep 19 2012: What's the source of your "straight line" theory? I'd like to look into it.
    • Sep 20 2012: Mark,
      you are right, it's really difficult if possible at all to understand , but you know, this gut feeling ... it prompts me that there is a point :)

      Thanks for sharing !
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        Sep 24 2012: Big Bang is most amazing to me because it implies to me that moon dust and you and I and distant galaxies are all things are basically the same stuff with a common origin and history.
        • Sep 25 2012: The idea ' what goes as one comes as many " is very old, actually. " I am the universe ; the universe is my body" This sacred intuition has been set in a scientific context, and that is quite recent . What puzzles me in BB theory is the idea of a beginning in no time/space zone out of nothing with no kind of intent . Maybe it is not a beginning and Bang is not necessary ?
          Frankly, i don't know :)

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