The Big Bang is often described as the beginning of everything. But the evidence behind modern cosmology tells a more precise story. It shows that the observable universe was once far hotter, denser, and smaller than it is today. It does not yet provide a confirmed account of what, if anything, preceded that early state.

This episode follows the evidence backward: expanding galaxies, the cosmic microwave background, the light elements formed in the first minutes, and the faint primordial variations that later became galaxies. These observations support the hot Big Bang model. Yet when the equations of general relativity are pushed toward the earliest imaginable instant, they reach a boundary where quantum gravity should matter and established physics can no longer give a reliable description.

Several possibilities remain under investigation. Time may have begun with the universe, making “before” an invalid question. A quantum no-boundary state may have replaced a sharp beginning. A prior contracting cosmos may have undergone a bounce. Inflation may have preceded the hot Big Bang, perhaps within a larger eternally inflating structure. Cyclic and string-inspired models offer other paths through the same unknown territory.

None has been confirmed. The most promising clues may lie in the cosmic microwave background and in primordial gravitational waves, which could preserve evidence from epochs light can never reveal. The question is not simply what existed before the Big Bang. It is whether time itself had a beginning.

This podcast uses artificial intelligence in its research, writing, production, and narration. Episodes are editorially reviewed before publication.

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YES OR NO: Did time exist before the hot Big Bang???????