The Cosmological Principle says that the universe is homogenous and isotropic. Doesn't this imply that our universe cannot be in finite size, but is finiteless? If it has a boundary, how can then the cosmological principle still be true for those heavenly bodies residing at the boundary of the universe?(adsbygoogle = window.adsbygoogle || []).push({});

If the universe has no boundary, how can we have R(t), where R is the radius of the universe in the Robertson-Walker metric? Or even in determining the future of our universe, for the different k values, 0, 1, and -1, eg, expanding forever, or Big Crunch etc.?

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# Cosmological Principle

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