July 4, 2022

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

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

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

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

There are new wrinkles in that cosmological argument, and it’s muddled. according to New study From cosmologists Daniela Pérez and Gustavo Romero, both from the Argentine Institute of X-rays, the universe has been expanding and contracting repeatedly, and large black holes are some of the only things that have 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 Perez and Romero study, which was published last month in the scientific journal. physical review d.

“Our main result is that the solution represents a dynamic black hole present in all periods of the cosmological regression model,” 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.

It’s a compelling discovery. The question of a black hole’s role in the rebounding universe is “clearly intriguing,” Leandros Perivolaropoulos, a physicist at the University of Ioannina in Greece who was not involved in the study, told The Daily Beast, “and this paper may be seen as an initial attempt to address it.” .

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

“General relativity itself breaks down in both the black hole singularity and the bounce singularity,” said Perivolaropoulos. “So any conclusion based on it cannot be taken seriously.”

In other words, the moment the universe collapses to its smallest size just before the bounce, gravity will stop 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. Therefore any conclusion based on it 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 several leading 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 expansion phase, and You can start contracting again In a hundred million years or so it is on its way to a new leap within a few billion or tens of billions of years.

Alternative theories of the ways the universe might end include the universe slowing down and freezing, collapsing on itself or spinning into countless fragmented pocket universes. Amid all the options, it’s clear why cosmic bounce is attracting so much attention. It’s a neat way of explaining some of the strange things we see around us in space.

First, it might help explain why there are such strange, scattered lumps of stuff in a mostly uniformly empty universe. Galaxies. stars. planets. People. Irregularities in space are a byproduct of infinite expansion and contraction.

Bounce might also make sense for the largest black holes. Specifically, the “enormous” variety that is billions of times larger than our sun and that 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 massive black holes using a new global set of radio telescopes called event horizon telescope. one observed At the center of our galaxy, the Milky Way. was the other Spotted in the heart of Messier 87a galaxy 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 directly observe with our telescopes. At the heart of an impossibly dense dark black hole, our understanding of the universe is crumbling. As Perivolaropoulos said.

There is something special about something this big and intense. This is something special that might 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 not by chance 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 can bounce back Back After it contracts once every 30 billion years or so.

According to Perez and Romero, there are reasons to believe that large black holes, still intact after the cosmic bounce, help the universe rebuild by returning material to space and mixing newly expanding matter with its energy.

“If black holes pass through the bounce, they can cause disturbances that would lead to structure formation and early formation of an expanding galaxy,” they wrote. Black holes can act as engines of creation or reconfiguration, 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 after contracting once every 30 billion years or so.

It’s an attractive idea. Especially in light of another theory that has gained credibility (in parallel 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 bouncing universe and supermassive black holes. Bernard Carr and Timothy Clifton from Queen Mary University of London, along with Alan Cooley from Dalhousie University in Canada, It was written about Black holes have survived the cosmic bounce for years now. “The math we’ve done suggests it’s possible,” Cooley told The Daily Beast.

The difference is that, in the model from Cooley and colleagues, 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 withstand even when the things inside the structure of the universe collapse in on themselves.

In Perez and Romero’s thinking, 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 powerful than anyone had previously imagined—and perhaps even more important to the universe’s new expansion.

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

To get a better treatment of the potential black hole-assisted cosmic bounce, we need to find more black holes. Especially the big ones in the centers of galaxies. We also need better measurements of the background radiation of the universe. An accurate radiation reading may indicate cycles of expansion and contraction.

The good news is that these observations may soon be possible. the new BICEP array, a group of four radio telescopes under construction at the South Pole, could give us good radiation readings starting in 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, as well as recording the telltale radiation patterns of the bouncing universe, we may need to start making peace with the idea that everything we can see and imagine is far less unique than we previously thought.

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