Black holes that formed before the Big Bang may have survived into the universe we observe today, according to new research from the University of Portsmouth. These ancient objects could act as “cosmic fossils” and may even help explain dark matter—the invisible substance that influences how galaxies and large-scale structures form.
The study examines the possibility that the universe did not begin with a single explosive event. Instead, researchers are exploring a cosmic bounce model, in which the early universe first contracted before reversing course and expanding. Under this scenario, some black holes from the pre-Big Bang universe may have survived the transition and continued to exist as cosmic fossils.
If supported by future evidence, primordial black holes could offer clues to several major mysteries in cosmology. They may help scientists determine the nature of dark matter and explain how the first galaxies and other large-scale structures formed so quickly in the early universe.
Rethinking the beginning of the universe
Professor Enrique Gaztañaga, lead author of the study from the Institute of Cosmology and Gravity at the University of Portsmouth and the Institute of Space Sciences in Barcelona, said: “For almost a century, cosmologists have traced the history of the universe to a single dramatic moment known as the Big Bang. The standard model states that space-time emerged from an extremely hot and dense state approximately 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.
“However, some of physics’ deepest mysteries remain unsolved. We still do not know what caused the Big Bang, why the universe began in such an unusual state, what triggered the brief period of rapid expansion known as inflation, or what dark matter is. Dark matter outweighs ordinary matter by approximately five to one.
“Our research explores whether these puzzles could be connected. The universe may not have begun with a single shock, but instead may have emerged from a cosmic bounce that mimicked inflation. Some of the universe’s oldest objects could also have survived as relics from an earlier cosmic era.”
Some black holes may have formed during an early contraction phase and passed through the cosmic bounce. If so, these relics could continue to influence the structure and evolution of galaxies billions of years later.
Other black holes may have formed shortly after the bounce, when density fluctuations became amplified. In this scenario, matter in the young universe would have been distributed in unusually dense concentrations. These regions would have been more likely to collapse under gravity, allowing galaxies, large cosmic structures and black holes to develop faster than expected.
Cosmic bounce instead of a singularity
According to Einstein’s theory of general relativity, tracing the universe backward leads to the Big Bang singularity, where density becomes infinite and the known laws of physics break down. Many physicists view this failure as evidence that current theories do not provide a complete explanation of the universe’s earliest moments.
Bounce cosmology offers an alternative. In this model, the universe begins as a vast, contracting expanse of matter and energy. Rather than collapsing into an infinitely dense singularity, it reaches an extremely high but finite density before reversing direction and expanding again.
Professor Gaztañaga added: “Singularities often indicate that a theoretical description has reached its limits. A cosmic bounce provides a way for the universe to transition from contraction to expansion without requiring entirely new or exotic physics.”
The researchers suggest that such a bounce could occur naturally through quantum effects. At extremely high densities, quantum pressure may become strong enough to prevent matter from being compressed indefinitely. Similar effects help stabilize dense objects such as white dwarfs and neutron stars and could potentially produce an expansion phase resembling cosmic inflation.
The model applies these processes to the universe as a whole. During the contraction phase, quantum pressure could eventually halt the collapse and drive the universe into a new period of expansion.
A possible connection between inflation and dark energy
Researchers say the cosmic bounce model could address two major mysteries in cosmology. First, it may help explain why the early universe underwent a period of rapid and remarkably uniform expansion known as inflation.
The same framework could also offer insight into the accelerated expansion of the universe today. Scientists generally attribute this acceleration to dark energy, although the fundamental nature of dark energy remains unknown.
Another important prediction is that some objects formed during the contraction phase could survive the bounce. The researchers calculated that compact objects larger than approximately 300 feet (90 meters) might pass through the transition and reappear once the universe began expanding.
Potential surviving relics include gravitational waves, density fluctuations and primordial black holes formed before the Big Bang.
Could ancient black holes make up dark matter?
These relic black holes could help explain dark matter. Although dark matter cannot be observed directly, its gravitational influence determines how galaxies form and how matter is distributed throughout the universe.
Researchers say that if enough black holes formed during the contraction phase, they could account for a significant portion of the universe’s dark matter. In principle, primordial black holes could even explain all of it.
The model may also shed light on puzzling observations from the James Webb Space Telescope. Webb has detected unexpectedly massive objects in the early universe, including sources sometimes described as “little red dots.” Many astronomers believe these objects may be associated with rapidly growing black holes that emerged much earlier than standard models predict.
“If a supermassive black hole already existed immediately after the bounce, we would not have to start from scratch when explaining the formation of the first galaxies in the early universe,” Gaztañaga said.
Searching for evidence from before the Big Bang
The cosmic bounce theory makes predictions that could be tested through future astronomical observations. Researchers may search for relic gravitational waves produced during the earliest stages of cosmic history.
Scientists could also look for subtle patterns in the cosmic microwave background that preserve information from a period before the Big Bang.
“A great deal of work remains to test these ideas,” Gaztañaga added. “But if the universe experienced a cosmic bounce, the dark structures shaping galaxies today could be remnants of a cosmic era that existed before the Big Bang.”
Source: www.sciencedaily.com