The Big Bang isn't science. It's philosophy. Theoretical physicists and astronomers aren't trying to understand their observations honestly (for the most part). they're attempting to explain their observations according to unguided, random naturalistic forces. That is a philosophical constraint, not a constraint based on observation.
When Hubble discovered that light from distant galaxies is equally red-shifted, it seemed to mean that the distant galaxies were moving away from the earth at an equal rate, and that seemed to suggest that the earth was located in the center of that phenomenon.
Well we can't have that, because that would mean the earth is in a special or favored location in the universe, and that would mean there is a mind and purpose behind our existence. So how do we explain it? All of 3d space is expanding! Like raisins in a muffin all move away from each other as the bread is baked because the dough is expanding, so we observe all other bodies moving away from us at equal rates because space is expanding.
We can't test that hypothesis. It's not even the simplest answer, but it's the favored answer, because those who govern the institutions of science prefer a naturalistic explanation.
When Hubble discovered that light from distant galaxies is equally red-shifted, it seemed to mean that the distant galaxies were moving away from the earth at an equal rate, and that seemed to suggest that the earth was located in the center of that phenomenon.
Well we can't have that, because that would mean the earth is in a special or favored location in the universe, and that would mean there is a mind and purpose behind our existence. So how do we explain it? All of 3d space is expanding! Like raisins in a muffin all move away from each other as the bread is baked because the dough is expanding, so we observe all other bodies moving away from us at equal rates because space is expanding.
We can't test that hypothesis. It's not even the simplest answer, but it's the favored answer, because those who govern the institutions of science prefer a naturalistic explanation.
…Such a condition would imply that we occupy a unique position in the universe, analogous, in a sense, to the ancient conception of a central Earth.…This hypothesis cannot be disproved, but it is unwelcome and would only be accepted as a last resort in order to save the phenomena. Therefore we disregard this possibility...the unwelcome position of a favored location must be avoided at all costs...such a favored position is intolerable….Therefore, in order to restore homogeneity, and to escape the horror of a unique position…must be compensated by spatial curvature. There seems to be no other escape . . .
https://ned.ipac.caltech.edu/level5/Sept04/Hubble/paper.pdf (p.40)
https://ned.ipac.caltech.edu/level5/Sept04/Hubble/paper.pdf (p.40)