Theoretical research suggests that the universe went through a phase of contraction before it began to expand. Black holes and gravitational waves that survived the transition may explain some of the dark matter and the early appearance of supermassive black holes.
Is it possible that some of the black holes in the universe are older than the Big Bang? A new theoretical study suggests just such a scenario: The universe did not begin at a single point where space and time emerged, but first went through a phase of contraction, reached a very high – but finite – density, and then “jumped” and began to expand.
In this scenario, known as a jumping universe cosmology, some of the structures created during the contraction phase could survive the transition and reappear in the expanding universe. Among the possible remnants: black holes, fluctuations in matter density, and gravitational waves. The study was published in the journal Physical Review D By Prof. Enrique Gastagnaga from the University of Portsmouth and the Institute of Space Sciences in Barcelona.
It is important to emphasize that this is a theoretical model and not the discovery of black holes from before the Big Bang. Researchers have not yet found such objects and have not proven that the universe actually went through a previous stage of contraction.
Not a complete beginning, but a transition between two stages
The conventional Big Bang model describes the evolution of a hot, dense universe and its expansion over about 13.8 billion years. It explains, among other things, the cosmic microwave background radiation and the large-scale distribution of galaxies. However, when general relativity is applied back to the earliest moments, it leads to a singularity – a state where the density becomes infinite and the equations cease to provide a useful physical description.
Jumping universe models attempt to replace the singularity with a smoother transition. The universe is contracting, but quantum effects create pressure that prevents matter from compressing indefinitely. After the contraction stops, a new phase of expansion begins.
Gastanyaga argues that the mechanism does not necessarily require the introduction of exotic matter or an arbitrary change in the laws of gravity. He says that pressure originating from quantum principles, similar to the pressure that stabilizes white dwarfs and neutron stars, could also operate on a cosmological scale.
How can a black hole survive a cosmic “jump”?
The paper describes two possible pathways for the formation of remnant black holes. In the first pathway, compact objects or gravitational disturbances created during the contraction of the universe escape beyond the causal horizon. As a result, they become dynamically “frozen” and may persist until after the expansion begins.
In the second path, the material in the contraction phase is concentrated in dense halos, similar to the halos within which galaxies form. The halos cross the horizon during contraction and then, when they re-enter the horizon in the expanding universe, they can collapse into black holes.
The model calculations indicate that disturbances or objects whose physical size at the critical stage is larger than about 90 meters may survive the transition. This does not mean that every 90-meter object from the previous universe survived, but that this is a theoretical threshold that depends on the specific assumptions of the model.
Possible candidates for dark matter
The remnant black holes may, according to the study, contribute to dark matter – the invisible substance whose gravitational influence is evident in the motion of stars and galaxies. If black holes were formed in the right quantity and mass range, they could explain some, or perhaps all, of the dark matter.
This is a different idea from the conventional scenario of primordial black holes, in which black holes are formed from density fluctuations in the young universe after the Big Bang. In the new model, at least some of the objects originated in the contraction period that preceded the cosmic jump.
However, the possibility that all dark matter consists of black holes is subject to severe observational constraints. Observations of gravitational lensing, the cosmic microwave background, and black hole collisions constrain their occurrence in different mass ranges. The present paper proposes a creation mechanism, but a detailed fit to all the data is still required.
Is the James Webb Space Telescope already seeing their offspring?
The model may also provide a possible explanation for the early emergence of massive black holes. The James Webb Space Telescope has discovered compact, red sources in the early universe, called “little red dots.” Some of these may contain rapidly accreting black holes.
If massive black hole “seeds” already existed immediately after the jump, they would not have had to be created from scratch within hundreds of millions of years. They could have served as the basis for the growth of the supermassive black holes found today at the centers of galaxies. However, this is only a possible explanation, and the nature of all the little red dots is still unclear.
How can one test an idea about a period before the Big Bang?
The study suggests looking for a unique background of gravitational waves that could have been created during the contraction phase and survived the jump. Another possibility is to detect patterns in the cosmic microwave background radiation or in the distribution of galaxies that do not fit the accepted inflationary predictions.
Anomaly populations of black holes – for example, objects in mass ranges that are difficult to explain by stellar collapse – may also provide clues. But discovering such black holes alone will not be enough: it will be necessary to show that their properties exactly match the model predictions and cannot be explained by known processes.
The idea of “cosmic fossils” opens up an intriguing possibility: The Big Bang was not necessarily the absolute beginning of everything, but rather a boundary between two chapters in the history of the universe. At this point, however, it is a hypothesis that needs to withstand many observational tests. The text provided for the news is based on a SciTechDaily article.
FAQ
Have black holes really been found that formed before the Big Bang?
No. This is a theoretical model, not an observational discovery. The researchers suggest that in a “jumping universe” scenario, certain black holes could have formed in a stage prior to the current expansion and survived the transition.
What is a jumping universe?
This is a cosmological model according to which the universe did not begin with a complete singularity, but first went through a phase of contraction. When the density reached a very high value, quantum effects stopped the collapse and led to the beginning of a new expansion.
How can a black hole survive such a transition?
According to the model, compact objects and sufficiently large density fluctuations may survive the jump phase without being destroyed. The calculations indicate that structures larger than about 90 meters in size under the described conditions could survive, but this is a theoretical threshold that depends on the assumptions of the model.
Could these black holes be dark matter?
It is possible, at least according to the scenario we tested. If a large enough population of remnant black holes were created, they could account for some, or perhaps all, of the dark matter. However, the prediction must be adjusted to existing observational constraints on black holes in different mass ranges.
How are they different from regular primordial black holes?
Primordial black holes are usually proposed to be objects formed from density fluctuations shortly after the Big Bang. In the new model, some black holes may have formed during the contraction phase that preceded the cosmic jump.
Does the model explain the giant black holes in the young universe?
He suggests a possible explanation. If massive black holes already existed immediately after the jump, they could have served as “seeds” from which the supermassive black holes observed in ancient galaxies rapidly grew.
How can the theory be tested?
One can look for unique backgrounds of gravitational waves, unusual signatures in the cosmic microwave background, or populations of black holes that are difficult to explain by ordinary stellar collapse. So far, no clear evidence has been found for a universe that predated the Big Bang.
Does the model disprove the Big Bang theory?
No. He does not deny that the universe was once hot and dense and has been expanding ever since. He suggests that the phase known as the “Big Bang” was not necessarily the absolute beginning, but rather a transition between a period of contraction and a period of expansion.
for the scientific article DOI: 10.1103/pr4p-6m49
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