New model of the Big Bang shows visible universe and invisible dark matter co-evolved

Physicists have long believed that there may be more to our universe than what we see. By observing gravity on other galaxies, they hypothesized the existence of “dark matter” that is invisible to traditional forms of observation.

“Ninety-five percent of the universe is dark and invisible to the naked eye,” said Pran Nath, the Matthews Distinguished University Professor of Physics at Northeastern University.

“However, we know that the dark universe is out there [its] The gravity of the star,” he said. Aside from gravity, dark matter never seemed to have much of an impact on the visible universe.

However, the relationship between these visible and invisible domains, especially when the universe was first formed, remains an open question.

Now, Ness says, there’s growing evidence that the two fields, thought to be separate, actually co-evolved.

Through a series of computer models, Ness and Dr. Candidate Kim Jong Lee discovered that what they call the visible and hidden regions likely co-evolved in the moments after the Big Bang, with profound consequences for the development of the universe since then.

There was a time, Ness said, when some physicists effectively eliminated this hidden part because we could explain most of what was happening in the visible range—that is, if our models could accurately depict what was happening around us. Why go to the trouble of measuring something that has no obvious effect?

“The question is, what impact does the implicit realm have on the explicit realm?” Ness asked. “But what do we care? We can explain everything.”

But Ness believes we can’t explain everything. Some anomalies appear to be inconsistent with the so-called “standard model” of the universe.

Ness said the separation of the visible and hidden parts from each other is a misconception, based on the assumption that the visible and hidden parts evolved independently of each other. Ness wanted to overturn this assumption.

In a paper published in Physical Review DIn “Big Bang Initial Conditions and Self-Interaction Hidden Dark Matter,” co-authored with Lee, Ness wants to ask what he calls “the more important question: How do we know they evolved independently?”

To test this hypothesis, Ness and his team “introduced some weak interactions between the two sectors” in their model of the Big Bang. These weak interactions are not enough to affect the results of particle accelerator experiments, “but we wanted to see what effect this would have on the entire visible light region,” Ness said, “from the beginning of the Big Universe’s explosion to the present time.”

Even if the interaction between the two parts is small, Ness and his team found that dark matter’s influence on the visible matter that makes us up could have a significant impact on observable phenomena.

For example, the Hubble expansion – in the simplest terms, galaxies are moving away from each other and therefore the universe is expanding – has a “pretty serious” discrepancy between the Standard Model’s predictions and what is observed. Ness’s model partially explains this difference.

One major variable is the temperature of the hidden region during the Big Bang.

We can be fairly certain that the visible light region was very hot to begin with at the Big Bang. As the universe cooled, Ness said, “What we’re seeing are remnants of that time in the universe.”

But by studying the evolution of the two regions, Ness and his team were able to model both scenarios—one hidden region that started out hot and the other that started out cold.

What they observed was surprising: Although there were significant differences between the models that had a major impact on the appearance of the early universe, both the hot and cold models were consistent with the visible region that we can observe today.

In other words, our current measurements of the visible universe are insufficient to confirm which side the hidden regions belonged to in the first place—hot or cold.

Ness is quick to point out that this was not a failure of the experiment, but an example of mathematical modeling exceeding our current experimental capabilities.

That’s not to say that the difference between hot or cold hidden regions has no effect on the visible universe, but we haven’t experimented with high enough precision yet. Ness mentioned the Webb telescope as an example of a next-generation tool capable of such precise observations.

The ultimate goal of all this modeling work is to better predict the state of the universe, how it works, and what we’ll find as we peer deeper and deeper into the night sky.

As our experiments become more accurate, questions in Ness’s model (are hidden regions hot or cold?) will be answered, and these clarifying models will help predict solutions to deeper questions.

“What’s the point?” Ness asked. Humanity, he said, “wants to find its place in the universe.” More importantly, “They wanted to answer the question, why is there a universe?

“We are exploring these questions. This is the ultimate human pursuit.”

This article is reprinted by Northeast Global News news.northeastern.edu.