Physicists reimagine origin of universe, questioning Big Bang theory

What if the Big Bang was not the beginning of everything but instead the result of a cosmic rebirth? A new paper published in Physical Review D and discussed in The Conversation proposes a radical idea. It suggests that our universe may have formed inside a black hole that was created during the collapse of a previous universe. This idea, known as the “black hole universe,” reimagines the beginning of time not as the creation of something from nothing but as part of an ongoing cosmic cycle.

The article highlights how the standard Big Bang model, despite its success in explaining the structure and evolution of the universe, leaves many important questions unanswered. The theory begins with a singularity, a point of infinite density where the laws of physics cease to apply. It also relies on cosmic inflation and dark energy, two ideas that help the model fit observations but depend on mysterious and unproven elements.

In contrast, the new model takes a familiar physical process and applies it on a grand scale. Instead of imagining the universe starting from a singularity, it looks at what happens when a dense region of matter collapses under its own gravity. This is similar to the way stars collapse to form black holes. The model suggests that at extreme densities, the quantum exclusion principle — a rule in quantum mechanics that prevents certain particles from occupying the same state — halts the collapse and causes the matter to bounce outward. This bounce gives rise to a new expanding universe.

The proposed bounce does not require exotic physics or extra dimensions. It relies only on general relativity and basic quantum mechanics. As the collapsing matter rebounds, it naturally enters two phases of accelerated expansion. These mirror what scientists call cosmic inflation in the early universe and the current acceleration driven by dark energy. Yet in this model, both arise from the bounce itself, not from unknown forces or fields.

One of the most compelling aspects of the theory is that it makes predictions that can be tested. It suggests that the universe has a small but positive curvature. This would mean the universe is slightly curved rather than perfectly flat, as the standard model assumes. If future space missions like Euclid detect this curvature, it would offer strong support for the bounce scenario. The model also aligns with current observations of cosmic expansion and may offer clues to the early formation of black holes and the distribution of dark matter.

The theory also offers a new perspective on humanity’s place in the cosmos. According to this view, our entire observable universe exists inside a black hole in a larger “parent” universe. This challenges the traditional idea of the Big Bang as the beginning of all things and places our universe within a grander cosmic story.

In short, while still theoretical, the black hole bounce model provides a bold and elegant alternative to the standard Big Bang narrative. It is rooted in known physics and offers a framework that can be tested by future observations. If proven right, it could transform our understanding of how the universe began — or rather, how it continued.

By Sabina Mammadli