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Showing posts with the label and the saddle-shaped surface is said to have negative curvature.

Shape of the observable universe

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As stated in the introduction, there are two aspects to consider: its local geometry, which predominantly concerns the curvature of the universe, particularly the  observable universe , andits  global geometry, which concerns the topology of the universe as a whole. The observable universe can be thought of as a sphere that extends outwards from any observation point for 46.5 billion light years, going farther back in time and more  redshifted  the more distant away one looks. Ideally, one can continue to look back all the way to the  Big Bang ; in practice, however, the farthest away one can look using light and other  electromagnetic radiation  is the  cosmic microwave background (CMB), as anything past that was opaque. Experimental investigations show that the observable universe is very close to  isotropic  and  homogeneous . If the observable universe encompasses the entire universe, we may be able to determin...