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

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In a uniform universe characterized by isotropy and homogeneity, the expansion of space is directed outward rather than inward, despite the potential for both directions to maintain symmetry. This outward expansion does not inherently lead to galaxies being pushed together; instead, it reflects the nature of cosmic expansion. The discussion emphasizes that isotropy and homogeneity do not dictate the direction of expansion, which could theoretically occur in either direction. The key takeaway is that uniform expansion preserves the symmetry of the universe, regardless of whether it is expanding or contracting. Thus, the outward push of space is a distinct characteristic of cosmic 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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