Comments by "carcdg" (@callanc3925) on "How We Know Space is Flat | Brian Cox and Joe Rogan" video.

@whydoesyoutubehaveahandlenow If youve ever seen people try explain einsteins theory of gravity on youtube - having a sheet stretched out and placing a bowling ball in the middle and watching a tennis ball roll towards where the bowling ball is - his analogy of a 2D universe is exactly the same as that. We reduce it by one dimension so we can picture whats happening. To picture the curvature of a 2D surface we need to add a third dimension and to picture the curvature of a 3D universe we need to add a fourth dimension. We cant perceive 4 dimensions so we think of space in 2 dimensions when necessary
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@ShakenPig Because joe asked a question and the fact that the universe is flat is part of the explanation. He cant just sit there and say "you guys wouldnt get it". In reality, the universe is flat, just like electrons have spin. Its just a different definition of flat that the majority of people dont comprehend because they didnt do post graduate astrophysics. Its not scientific loopholes its rigorous mathematics based on observations that leads to those definitions Maybe i should ask you the question of why did you watch a podcast with brian cox if youre just going to call anything you dont understand "scientific loops"
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@ShakenPig Then your point is meaningless. Flat doesnt have to mean like the surface of a table and be inherently 2 dimensional. Electrons have a value for "spin" despite not actually spinning. This quality about them is called spin because in mathematical descriptions of the electrons angular momentum, it works out almost exactly the same as how the rotation of a ball contributes to the balls angular momentum. It doesnt mean the electron is actually "spinning" in the classical sense, thats just what they chose to call the phenomena because of similarity. Its the same thing with the universe being flat. Its not flat in the "surface of a table" sense, but the phenomena of the universe being "flat" are likely very similar in some way to that of a table being flat.
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@ShakenPig Youre not understanding the analogy then. "flat" in 3 dimensions isnt perceivable, so they reduce space to 2 dimensions so that people can understand it
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