Am I at the centre of the Universe?



Seeing distant objects is looking at their past. I could thus look at the Big Bang by looking far enough, and this in all directions. Doesn’t it mean that I am at the centre of the Universe?




The answer is no. Imagine a point (A) at 14 billion light-years from you (O), which corresponds basically to the Big Bang (left figure below). Then place an observer at point A today (right figure below), what does this observer see? Presumably, exactly the same thing as you.

But that seems impossible, because we (at O) are at a distance of 14 billion light-years from A, and we know that we are not at the Big Bang!


Well, you forgot that we see in time and space. In the left figure (see below), O corresponds to now, and thus A to the Big Bang era. In the right drawing, A is an observer now, and thus it sees the point O at the time of the Big Bang, 14 billion years before we appeared on Earth!


You may note that A sees a similar sky as O, but each star or galaxy is viewed at a different time (depending on the respective distances to A or O).

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