We are given the diameter of the Universe to be approximately 880 Ym. Is this the the distance observed at any place when looking into space, or is this value more of an average?
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Related: https://physics.stackexchange.com/q/26549/123208 – PM 2Ring Jun 18 '21 at 01:01
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1Are you referring to the likely scenario where there isn't an object exactly at the edge of the observable universe in every possible direction to actually observe and measure distance to? – DKNguyen Jun 18 '21 at 01:02
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According to https://en.wikipedia.org/wiki/Orders_of_magnitude_(length) (at the bottom just above Notes) the approximate diameter of the observable universe (see Wikipedia) is 886.48 Ym = 93.7 billion light-years. The observable universe is a sphere including everything inside it that in principle have emitted the photons which in principle are observable to observers on Earth now, ignoring that some photons which could come all the way to Earth might not make it due to hitting something along the way. At the boundary of this sphere what is there is moving away from us at the speed of light, and therefore its photons can not reach us now, but a second later its photons do reach us because the observable universe radius grows at the speed of light, so what was previously at the boundary produces photons which in principle can reach Earth then but photons produced from very close to the boundary will be red-shifted so much we might not be able to detect them even if they did not hit stuff in the way.
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