They propose a possible origin for the enormous bodies located in the centre of many galaxies: supersonic currents of gas formed after the origin of the Universe accumulated and collapsed, generating these objects.
An international team of researchers has succeeded in developing a computer simulation to explain and recreate the formation of the first supermassive black holes , those colossal accumulations of energy and mass (which have a mass comparable to hundreds or billions of soles) and which are at the center of many galaxies, such as the Milky Way . The study, published this Thursday in Science, has shown that supersonic gas currents formed after the Big Bang could be the explanation for the appearance of these objects so important in the evolution of the Universe.
“It’s a significant breakthrough,” Naoki Yoshida, the study’s lead author and researcher at the Kavli Institute of Physics and Mathematics of the Universe, said in a statement. “The origin of the monstrous black holes has always been a mystery and now we have a possible solution .”
Astronomers have been able to see supermassive black holes at a distance of 13 billion light-years when the Universe was barely five percent of its present age. But none of his theories have so far been able to explain how the birth of these bodies was in those early stages. This implies that an important part of how the visible Universe was born today is unknown and that theories have passed something very important.
The seed: the gravitational collapse
Scientists have given several possible explanations. They suggested that supermassive black holes could have formed after the death of the first generation of stars that appeared in the Universe. Or that its origin would be in the cloud of primordial gas, that mass of gas formed after the Big Bang, before the stars. According to this idea, it could be that the birth of black holes was related to the gravitational collapse of this gas. What does this mean? This collapse occurs when a large mass accumulation generates such a strong gravitational pull that it even exceeds the resistive capacity of the atoms. That is why, in theory, the collapse progresses out of control and nothing can stop it until it generates a singularity: the black hole.
On this occasion, Yoshida and his colleague Shingo Hirano, a researcher at the University of Texas, Austin, USA, looked at a possible mechanism for generating supermassive black holes with sufficient speed. The key was to take into account the supersonic movement of gas trapped by dark matter, that strange entity that generates gravity in the tissue of the Universe but is not associated with anything that can be seen directly through any instrument.
Mathematics to see further
At the moment, there is no way to see what happened directly when the Universe was taking its first steps, and may never be possible. But scientists can develop computer models to use the data collected by astronomers and get results. Keeping distances, the process reminds you of the operation of a Thermomix: you enter data (ingredients) and the machine processes them (following the instructions of a “recipe”) to obtain results also in the form of numbers (processed food). If it turns out that these conclusions are compatible with the things that are observed through the telescopes, it is because the model has given with an explanation, at least plausible, on what is being studied: in this case the origin of the supermassive black holes older.
On this occasion, and thanks to the massive calculations of a supercomputer, the simulations showed that only 100 million years after the Big Bang formed a great accumulation of dark matter. The supersonic gas currents, originated in the great explosion, were captured by these mass accumulations. Thus, in very brief times, the gas concentrated and formed huge and turbulent clouds of gas, within which the germs of immense stars could be quickly formed.
” Once they reached a mass of 34,000 soles, the stars collapsed by their own gravity, and gave way to black holes,” said Yoshida. “These massive black holes born in the early Universe continued to grow and fuse with others into supermassive black holes,” the astrophysicist proposed. These are the ones we can see today through powerful telescopes.
The density of black holes
Simulations are simulations and reality is the reality. But the truth is that the model used by these researchers has predicted a universe in which there would be a number of supermassive black holes similar to what actually exists: with a density of about one for every 3 billion cubic light years (this is the volume that is comprised in a cube of 3 billion light years of side).
This research will be important for future research analyzing the growth of large black holes. In addition, it is expected that in the coming years the powerful James Webb space telescope will accelerate this area thanks to its ability to observe the Universe more distant and therefore older.
Thus, it seems that with the Big Bang , in an impossible instant the time began to run. And with its matter, energy and space “sprouted” in all directions. From a singular point in which all the energy was concentrated, in a matter of seconds, the expansion allowed the appearance of the simplest possible atoms: those of hydrogen and helium. In theory, it took billions of years for light to appear, and for the primordial gas to agglutinate and form stars, galaxies and also black holes. But how did this happen? When and why did the first supermassive black holes appear? This is what we are still trying to understand. The recipe to achieve this is to use increasingly powerful telescopes, and perhaps to use the information of gravitational waves, and to make simulations by means of an observer that can explain the phenomena that can be observed.