A new cosmic bounce model suggests that remnants from a pre-Big Bang Universe may still exist today.
What if some of the Universe’s oldest objects are actually older than the Big Bang itself?
A new study from the University of Portsmouth suggests that ancient black holes may have survived from a time before the Universe as we know it existed. These hypothetical relics, described as “cosmic fossils,” could have endured a dramatic cosmic transition and may still be scattered throughout the cosmos today. If they exist, they could help solve one of astronomy’s biggest mysteries: the identity of dark matter, the invisible substance that appears to outweigh ordinary matter and shape the growth of galaxies.
The research challenges the conventional view that everything began with a singular Big Bang. Instead, it explores a “bounce” scenario in which the Universe was once contracting before reversing into the expansion we observe today. In that picture, some structures may have survived the transition, carrying information from a cosmic era that predates the Universe’s earliest observable light.
Challenging the Standard Big Bang Picture
Professor Enrique Gaztañaga, lead author of the study from the University of Portsmouth’s Institute of Cosmology and Gravitation and the Institute of Space Sciences in Barcelona, said: “For almost a century, cosmologists have traced the history of the Universe back to a single dramatic moment known as the Big Bang. In the standard picture, space and time emerged from an extremely hot, dense state around 13.8 billion years ago, followed by billions of years of cosmic expansion and galaxy formation.
“This model has been remarkably successful. It explains the Cosmic Microwave Background – the faint radiation left over from the early Universe – and accurately predicts how galaxies are distributed across vast cosmic distances.
“But some of the deepest mysteries in physics remain unresolved. We still don’t know what triggered the Big Bang, why the Universe began in such a special state, what caused the brief burst of rapid expansion known as inflation, or what the invisible ‘dark matter’ is that outweighs ordinary matter by about five to one.
“Our research explores a possibility that could connect several of these puzzles: the Universe may not have begun with a singular bang at all, but instead emerged from a cosmic bounce mimicking inflation, with some of the oldest objects in the Universe potentially surviving as relics from before it.”
According to the researchers, some black holes may have formed before the bounce and persisted through the transition into the expanding Universe. These ancient objects could still affect the structure and evolution of galaxies billions of years later.
Other black holes may have formed shortly after the bounce. In this scenario, unusually large density fluctuations in the early Universe would have created dense concentrations of matter that collapsed more easily under gravity, helping black holes and other large cosmic structures form at an early stage.
A Universe That Bounces Instead of Beginning
In Einstein’s theory of general relativity, the Big Bang is associated with a singularity, a state where density becomes infinite and the known laws of physics no longer apply. Many physicists view this as evidence that current theories cannot fully describe the Universe’s earliest moments.
One proposed alternative is a bouncing cosmology. In this model, the Universe begins as an enormous cloud that contracts before reversing direction and expanding again. Rather than reaching an infinite singularity, it attains an extremely high but finite density before rebounding.
Professor Gaztañaga added: “Singularities often signal that our theoretical description has reached its limits. A bounce provides a way for the Universe to transition from contraction to expansion without requiring new exotic physics.”
Explaining Inflation, Dark Energy, and Dark Matter
The team argues that such a bounce could emerge naturally from quantum physics. At extremely high densities, quantum effects can generate pressure that prevents matter from being compressed indefinitely, a process already known to stabilize dense objects such as white dwarfs and neutron stars and reproduce the inflationary expansion phase.
In the new model, the same type of quantum pressure could operate on the scale of the entire Universe. As contraction progresses, that pressure could stop the collapse and trigger renewed expansion.
The researchers suggest this mechanism may also address two major cosmological puzzles. It could help explain inflation, the period of rapid and remarkably uniform expansion in the early Universe. It may also offer insight into the present-day acceleration of cosmic expansion, which is commonly attributed to dark energy.
One particularly intriguing prediction is that some structures created during the contracting phase may have survived the bounce. The team’s calculations indicate that compact objects larger than about 90 meters (295 feet) could pass through the transition and emerge in the expanding Universe.
Potential relics include gravitational waves, density fluctuations, and ancient black holes.
These surviving black holes could also be linked to dark matter. If enough formed during the bounce, they might account for a substantial portion of dark matter, or possibly all of it.
Clues in the Early Universe
The model may also help explain recent James Webb Space Telescope observations of unexpectedly massive objects in the young Universe, often referred to as “little red dots.” Many astronomers believe these sources are associated with rapidly growing black holes that appeared surprisingly early in cosmic history.
“If massive black holes already existed immediately after the bounce, the early Universe would not need to start from scratch when building the first galaxies,” Gaztañaga said.
The theory offers several ways to test its predictions. Future observations could search for relic gravitational waves from an earlier cosmic era or look for subtle signatures in the cosmic microwave background that preserve evidence of conditions before the Big Bang.
“Much work remains to test these ideas,” Gaztañaga added. “But if the Universe did experience a bounce, the dark structures shaping galaxies today could be remnants from a cosmic epoch that preceded the Big Bang.”
Reference: “Cosmological bounce relics: Black holes, gravitational waves, and dark matter” by Enrique Gaztañaga, 24 February 2026, Physical Review D.
DOI: 10.1103/pr4p-6m49
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