In general relativity, the geodesics represent the paths that free-falling particles or objects follow in curved spacetime. These paths are the equivalent of the shortest path … See more

Current astronomical observations, show that the universe is expanding, thus the BGV implies that there must be a boundary or … See more

Vilenkin has also written about the religious significance of the BGV theorem. In October 2015, Vilenkin responded to arguments made by … See more

• Calcagni, Gianluca (2017-01-06). Classical and Quantum Cosmology. Springer. ISBN 9783319411279. See more

For FLRW metric
Here is an example of derivation of the BGV theorem for an expanding homogeneous isotropic flat universe (in units of speed of light … See more

Alternative models, where the average expansion of the universe throughout its history does not hold, have been proposed under the notions of emergent spacetime, eternal inflation, … See more

• Kalam cosmological argument
• Gibbons–Hawking–York boundary term
• Gibbons–Hawking effect
• Penrose–Hawking singularity theorems See more