A new theory in physics suggests that black holes are key to the universe’s expansion and contraction cycles

The universe is expanding. No one with experience in astronomy or physics disagrees with this fact.

Likewise, no one really disputes the fact that at some point, several billion years into the future, the universe will expand. so far– Running out of energy for further expansion. At this point, something has to change. This is where the controversy begins.

There are new wrinkles in this cosmological argument, and it’s muddled. According to a new study by cosmologists Daniela Pérez and Gustavo Romero, both from the Argentine Institute of X-rays, the universe has repeatedly expanded and contracted, and supermassive black holes were among the only things that survived these endless cycles of destruction and renewal. These cycles are part of what cosmologists call a potential “cosmic bounce.”

The mathematical model of a theoretical black hole is the focus of the peer-reviewed study Perez and Romero, which was published last month in the scientific journal. physical examination d.

“Our main result is that the solution represents a dynamic black hole that is present in all periods of the cosmic rebound pattern,” they wrote.

In other words, Perez and Romero’s black hole survived even as everything around it was wiped out as the universe collapsed on its way to a final recovery.

This is a convincing result. The question of the black hole’s role in the rebounding universe is “clearly interesting,” and this paper can be considered a first attempt to address this, said Leandros Perivolaropoulos, a physicist at the University of Ioannina in Greece who was not involved in the study.

But beware: there are a lot of assumptions in Perez and Romero’s argument. It is possible that the moment the universe jumps from contraction to expansion, all the rules that guide our understanding of physics disappear. Perhaps we are trying to understand the unfathomable.

“General relativity itself collapses in both the black hole singularity and the bounce singularity,” said Perivolaropoulos. Thus, any conclusion based on this cannot be taken seriously.”

In other words, the moment the universe collapses to its smallest size before rebounding, gravity stops working normally. This is what we mean by singularity: an exception to the laws of physics. We have no idea how a black hole will behave when the rules are not in place.

Perivolaropoulos added that Perez and Romero’s methods “have great potential for improvement, to put it mildly”.

General relativity itself breaks down in both the black hole singularity and the recoil singularity. Thus, any conclusion based on this cannot be taken seriously.

Leandros Perivolaropoulos, University of Ioannina

To be clear, the basic idea that the universe is expanding and contracting repeatedly is not new. Cosmic regression is one of the main theories among cosmologists who study the origin and fate of the universe.

In fact, at least one team of scientists believes that our 13.7-billion-year-old universe is at the end of its latest phase of expansion, and could begin to contract again in a hundred million years, on the way to a new recovery in a few billion years. Or even tens of billions of years.

Alternative theories for how the universe might end include the universe slowing down and freezing, collapsing on itself, or splitting into countless fragmented pocket universes. Of all the options, it’s clear why cosmic bounce is getting so much interest. It’s a great way to explain some of the strangest things we see around us in space.

For one thing, it might help explain why, in the vast majority of it being uniformly empty, we have these weird, scattered lumps of stuff. Galaxies. stars. planets. People. Irregularities in space that are a byproduct of infinite expansion and contraction.

The bounce could also mean the existence of larger black holes. Specifically, the “enormous” variety that is billions of times larger than our sun and exerts such a strong gravitational force on the space around them that not even light can escape.

So far, we’ve detected two of these supermassive black holes using a new global group of radio telescopes called the Event Horizon Telescope. One is observed at the center of our Milky Way galaxy. The other was spotted in the heart of Messier 87 galaxies 54 million light-years away.

A black hole contains the closest thing to a singularity – an exception to the accepted rules of physics – that we can observe directly with telescopes. In the impossibly dark and dense core of a black hole, our understanding of the universe is collapsing. As Perivolaropoulos said.

There is something special about such a large and dense object. And this special thing could help the largest black holes survive every time the universe bounces back and everything else is compressed into a kind of soft dough of matter and energy.

Their survival may be the key. Perhaps, just maybe, it is no coincidence that black holes endure and retain their unique strangeness, when everything around them shrinks into homogeneity. Black holes may be one of the reasons why the universe is able to bounce back return After one of its contractions once every 30 billion years or so.

According to Perez and Romero, there is reason to believe that large black holes, still intact after the cosmic bounce, are helping the universe rebuild itself by pumping matter back into space and mixing newly expanding matter with its energy.

“If the bouncing black holes cross, they can produce perturbations that would lead to structure formation and early formation of galaxies in the expansion phase,” they wrote. Black holes can act as engines of creation or recreation, if you will, helping to form galaxies, stars, and planets into a rebounding galaxy.

Black holes may be one reason why the universe is able to bounce back from one of its contractions once every 30 billion years or so.

It’s an attractive idea. Especially in light of another theory gaining credence (along with the idea of ​​cosmic bounce) that there are supermassive black holes at the center of every galaxy. We haven’t found them all yet.

To be fair, Perez and Romero aren’t the first cosmologists to explore the relationship between the boomerang universe and supermassive black holes. Bernard Carr and Timothy Clifton of Queen Mary University of London, along with Alan Cooley of Dalhousie University in Canada, have written about black holes having survived cosmic bounces for years now. “The calculations we’ve made indicate that this is possible,” Cooley told the Daily Beast.

The difference is that, in Cooley and his co-authors’ model, black holes are embedded in the surrounding structure of a shrinking universe rather than contained within it. This would make it easier for black holes to survive, even if the elements within the structure of the universe collapsed in on themselves.

In the thought of Perez and Romero, black holes are like that Inside the structure. “They’re looking at a slightly different model,” Cooley said. In this concept of a rebounding universe, black holes are more fluid than anyone previously imagined—and perhaps even more important to the further expansion of the universe.

If there’s a danger in the corner of cosmology that Perez and Romero share with Cooley and their co-authors, it’s that the hard data about rebounding universes and supermassive black holes are pretty weak. Our space probes are few and far between. We can only see so far with old telescopes.

To better understand the potential black hole-assisted cosmic bounce, we need to find more black holes. Especially the larger galaxies in the center of galaxies. We also need better measurements of the background radiation of the universe. An accurate reading of the radiation can indicate cycles of expansion and contraction.

The good news is that such views may become possible soon. The new BICEP network, a group of four radio telescopes under construction at the South Pole, could give us good radioactive readings from the next few years. And we can expect more images (and even some movies) of large black holes from the Event Horizon Telescope.

If cosmologists like Perez, Romero, and Cooley start finding black holes everywhere and also recording radiation patterns emanating from the bouncing universe, then perhaps we should start making peace with the idea that everything we can see and imagine is much less distinct than we previously thought.

In fact, we could be living in the third, hundred, or thousandth version of the universe after repeated bounces, each partly fueled by ever-larger black holes.