Why does the expansion of space in a uniform universe only push outward?

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The discussion addresses the nature of space expansion in a uniform universe, emphasizing that the isotropic and homogeneous characteristics do not dictate the direction of expansion. It clarifies that the expansion is inherently outward, regardless of the uniformity in appearance across directions and locations. The key takeaway is that while isotropy and homogeneity allow for uniform expansion or contraction, they do not influence the specific vector of that expansion.

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In an isotrophic and homogeneous cosmos, why would the expansion of space be specifically be vectored outward. Should it not also push galaxies together?
 
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The outward nature of the expansion is (in this case) unrelated to the isotropy and homogeneity of the universe. It could be either inward or outward, and still both isotropic and homogenous.

Remember that isotropic means the same in all directions (i.e. no matter which direction you look, things look the same); and homogenous means the same in all places (i.e. no matter where you go, things look the same). As long as space was uniformly expanding or contracting, it would preserve the same symmetry.
 

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