The ring of darkness in this galaxy cluster, Cl 0024+17, indicates the presence of dark matter. Credit: NASA, ESA, M.J. Jee and H. Ford (Johns Hopkins University)
A group of researchers suggests that a dark Big Bang may also have occurred at the origin of the universe. That is, it would have happened alongside the traditional Big Bang. His reasoning is that this phenomenon could have been the source of the dark matter that we can find in the cosmos…
It is important to be clear, as with any hypothesis of this style, that we are talking about something that must be treated with a lot of skepticism. The standard cosmological model is used to explain what the cosmos is like. In its early days, the universe was a very different and exotic place. One of the highlights, despite being incredibly brief, was inflation. In just a fraction of a second, long before the first second of the cosmos’ existence was fulfilled, an excessive expansion took place.
At the end of inflation, the observable universe went from being less than a molecule in size to having a radius of light-years. When the inflation ended, the exotic quantum fields, which allowed this phenomenon, degraded. They became a stream of particles and radiation that continues to exist today. When the universe was twenty minutes into existence, those particles began to come together. Thus, they gave birth to the first protons and neutrons in the cosmos. It was in a period called primordial nucleosynthesis.
It is one of the foundations of modern cosmology. The calculations, to explain this episode, detail precisely the amount of hydrogen and helium that can be observed in the universe. But it is true that, despite this, there are things that are still not well understood. One of them is dark matter. It is a form of invisible matter, which only interacts with gravity. However, it is the most abundant matter in the cosmos. In fact, dark matter is about five times more abundant than normal matter.
Generally, what is posited in Big Bang models is that the process that generated the particles and radiation also created the dark matter. A team of researchers now proposes an idea that is intriguing. What they argue is that the eras of inflation and primordial nucleosynthesis were not unique. Dark matter, perhaps, evolved in parallel, following a completely different path. In this scenario, the end of inflation flooded the universe with particles and radiation, but did not add dark matter.
In their place, some of the quantum fields remained, which did not degrade. As the universe expanded and cooled, that extra quantum field morphed, over time, triggering the formation of dark matter. This would therefore be the dark Big Bang. This approach has its advantages. It makes it possible to separate the evolution of dark matter from normal matter. So primordial nucleosynthesis takes place as described, while dark matter evolves separately.
This also opens other avenues of exploration. It makes it possible to analyze different theoretical models on dark matter, based on the assumption that it followed its own evolutionary path. This should make it easier to follow the calculations to see how they compare with the observations. For example, researchers have been able to determine that if that dark Big Bang really happened, it must have taken place before the universe was one month old. That is, it would not have happened next to the traditional Big Bang
This also opens other avenues of exploration. It makes it possible to analyze different theoretical models on dark matter, based on the assumption that it followed its own evolutionary path. This should make it easier to follow the calculations to see how they compare with the observations. For example, researchers have been able to determine that if that dark Big Bang really happened, it must have taken place before the universe was one month old. That is, it would not have happened next to the traditional Big Bang
After all, it is not even clear that there is any sign that a dark Big Bang took place. Although it is true that, in its favor, the study proposes methods that would allow these gravitational waves to be detected. It is not the first hypothesis that arises around the beginning of the universe. It won’t be the last either. The reality is that, except for those that state that the universe began with a Big Bang, all the others end up being discarded or, in the best of cases, have very little support, because they fail to explain known aspects of the cosmos.
In the future, it will be necessary to see if this hypothesis ends up giving rise to some interesting approach. For now, do not make the mistake of giving it more importance than it has. That is, it is by no means a revolution. It is only an approach that could be more or less attractive. At least, there is a positive reading. It is a reminder that dark matter, one of the great enigmas of modern cosmology, remains a never-ending field of research. Will we get to know her better in a few years?
source: https://arxiv.org/abs/2302.11579