A recent cosmology This model combines two of the most eccentric ideas in contemporary physics to explain the nature of dark matter, the invisible substance that makes up about 85 percent of all matter in the universe. To understand this, we must look beyond the Big Bang we all know and consider two concepts that rarely intersect: cyclical universes and primordial black holes.
Another type of multiverse
There are different versions of the “multiverse”. The most popular model – that of the Marvel Cinematic Universe – proposes that there are as many universes as there are possibilities and that these versions of reality are parallel. Physics offers something more sober and mathematically coherent: the cosmic rebound.
In this model, the universe does not arise from a singularity, but expands, contracts, and expands again in an endless cycle. Each “universe” is not parallel, but sequential, that is to say that one universe is born from the ashes of the previous one.
Is it possible for something to survive the end of its universe and continue into the next? According to an article published in Physical examination DYes. Author Enrique Gaztanaga, a research professor at the Barcelona Institute of Space Sciences, shows that any structure larger than about 90 meters could weather the final collapse of a universe and survive the rebound. These “relics” would not only persist, but could also give rise to the formation of giant and unexplained structures observed in the early stages of the current universe. Additionally, they could be the key to understanding dark matter.
For decades, the dominant explanation for dark matter was that it was one or more unknown particles. But after years of experiments without direct detection, physicists began to explore alternatives. One of them proposes that dark matter is not an exotic particle, but an abundant population of small black holes that we neglect.
The idea is attractive, but it poses a serious problem. For these black holes to explain dark matter, they would have to exist from the earliest moments of the universe, long before the first stars could collapse. There are indications that these objects may exist, but a convincing physical mechanism to explain their origin is lacking.
A universe born with black holes
This is where the new model offered by Gaztanaga shines. If cosmic rebound allows compact structures to survive the collapse of the previous universe, then the current universe would have already arisen with pre-existing black holes. They should not have been generated by extreme fluctuations or finely tuned inflationary processes, but would simply have been there from the first moment.
This hypothesis could potentially solve two puzzles at once: the origin of black holes and the nature of dark matter. If this model is correct, dark matter would not be a mystery of the early universe but rather a legacy of a cosmos prior to ours.
“A lot of work remains to be done,” Gaztanaga, also a researcher at the Institute of Cosmology and Gravitation at the University of Portsmouth, said in an article for The conversation. “These ideas need to be tested against data, from gravitational wave backgrounds to galaxy studies and precision measurements of the cosmic microwave background.”
“But the possibility is profound,” he added. “The universe may not have started just once, but it may have bounced around. And the dark structures that shape galaxies today could be relics from a time before the Big Bang.”
This story was originally published in WIRED in spanish and was translated from Spanish.