The Big Bang is widely known as the moment when the universe began—an explosion that created space, time, and all matter.
But a new theory challenges this idea, suggesting the Big Bang may not have been the true beginning.
Instead, it may have been the result of a massive gravitational collapse, like the formation of a black hole, followed by a cosmic “bounce.”
In a new paper published in Physical Review D, physicists propose that our universe might have formed inside a black hole.
This “black hole universe” idea may sound wild, but it is based on well-known physics, using tools from Einstein’s theory of general relativity and quantum mechanics—without needing strange, hypothetical ingredients like extra dimensions or unknown energy fields.
For years, scientists have relied on the standard model of cosmology, which starts with the Big Bang and includes a period of rapid early expansion known as inflation.
This model explains the structure and expansion of the universe very well.
But it leaves some big questions unanswered, such as what happened before the Big Bang, what caused inflation, and why the universe looks so flat and smooth.
One major problem is the Big Bang’s singularity—a point of infinite density where the laws of physics break down. This makes it difficult to understand what the universe was like at the very start.
The new model turns the problem around. Instead of asking what happened when the universe expanded, it starts by imagining a collapse.
When a massive cloud of matter collapses, it forms a black hole. This is something we already understand well in astrophysics. But what happens inside a black hole is still mysterious.
The team’s calculations show that, under the extreme conditions inside a collapsing black hole, quantum mechanics plays a key role. A principle called the “quantum exclusion principle” prevents matter from collapsing forever. Instead, the collapse slows down and then reverses—creating a bounce that launches a new, expanding universe.
This bounce, the researchers argue, looks a lot like our own universe’s beginning. Their equations show it could explain both early rapid inflation and the current acceleration of the universe’s expansion—without adding any exotic unknown forces. Even better, the model makes testable predictions. For example, it predicts the universe should have a slight positive curvature—like a gentle curve instead of being perfectly flat. If future space missions like the Euclid telescope confirm this, it would support the bounce theory.
The model also hints at answers to other cosmic puzzles, like how the first giant black holes formed or how galaxies evolved. Some leftover objects from the collapsing phase may still exist in our universe today.
Perhaps most fascinating is the idea that our entire universe may exist inside a black hole in another universe. If so, the Big Bang wasn’t the beginning—it was a transition. Just as Earth was once thought to be the center of everything, and we later learned it’s part of a much larger system, we may now be discovering that our universe is part of a bigger cosmic cycle shaped by gravity and quantum rules.
Source: The Conversation.
