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In real time, the universe has a beginning and an end at singularities that form a boundary to space-time and at which the laws of science break down.

Stephen W. Hawking (2003). “The Illustrated Theory of Everything: The Origin and Fate of the Universe”, New Millenium
In real time, the universe has a beginning and an end at singularities that form a boundary to space-time and at which the laws of science break down.