New discoveries from the James Webb Telescope indicate that supermassive black holes arose before galaxies
The age-old question about precedence between galaxies and their supermassive black holes may have found a definitive answer. Although both evolved together, the question of which came first remained open for a long time. As columnist Leah Crane points out, recent evidence seems to tip the scales.
Using novelist and philosopher Samuel Butler’s famous 1878 analogy, which describes a chicken as the method of one egg generating another, we can extend this logic to the cosmic relationship: a galaxy is perhaps just the means that one black hole employs to give rise to another. Faced with this ancient dilemma of precedence, the balance now tips towards black holes.
Observations of all massive galaxies in the universe reveal the presence of a supermassive black hole at their centers. This connection is intrinsic, where the galactic mass nourishes the black hole, which, in turn, influences the evolutionary trajectory of the galaxy itself. The origin of this complex interaction, however, has always been a fundamental mystery in cosmology. The question persisted: does the black hole establish itself first and attract material to form a galaxy, or does a galaxy develop and then its core collapses, giving rise to a black hole?
A central aspect of this enigma lies in the apparent difficulty in justifying the formation of supermassive black holes. Their colossal size seems to defy the initial conditions of existence, especially since they emerged less than 500 million years after the Big Bang. Although this interval may sound long for growth, a temporal analogy reveals the scale of the problem: if the history of the universe were one year, with the Big Bang on January 1st and the present day on December 31st, the first supermassive black holes would have already reached hundreds of millions of times the solar mass by mid-January. The laws of physics, in their current understanding, do not offer a clear path for such a massive and accelerated development.
Currently, four mechanisms are proposed for the formation of supermassive black holes. The most direct involves the union of black holes of stellar mass, which originate from the collapse of giant stars – however, the life cycle and fusion of these stars would require hundreds of millions to billions of years, a time that did not exist in the early days of the cosmos. The second theory suggests the formation of a “massive seed”, possibly one of the first stars, called primordial, or a dark matter star, or even a star cluster. However, this hypothesis only shifts the challenge, as the creation of such a seed would still require a considerable period of time in the first 500 million years of the universe, an insufficient period. Thus, two alternatives remain most plausible: direct collapse, where a vast cloud of gas, inhibited from forming stars by strong radiation, collapses directly into a black hole, and the existence of primordial black holes.
Primordial black holes represent an area of intense controversy, given the absence of concrete evidence for their existence, despite their potential usefulness for cosmic understanding. Although they are even more exotic concepts, the columnist expresses personal skepticism, but the hope that they exist. If confirmed, they would have arisen in the initial moments after the Big Bang, not from the collapse of stars (non-existent at the time), but from the extreme pressure of the nascent universe. Although the greatest interest generally revolves around their potential smallness compared to other types, for the context of galactic formation, the relevant type would, in fact, be colossal, as they originated in large dimensions and before any other structure.
If primordial black holes are a reality and can explain the accelerated and massive growth of supermassive black holes at the beginning of the universe, we would then have a conclusive solution to the cosmic chicken and egg question. In this scenario, galaxies could not have formed at as early a stage as these black holes. However, until recently, evidence supporting this hypothesis was lacking.
Leia Também
Devastating earthquake in Venezuela kills Héctor Bello’s wife and baby survives in rubble
Strong earthquake in Venezuela kills wife of player Héctor Bello while baby survives the rubble
Japanese striker Kento Shiogai minimizes Neymar and says that Brazil is no longer scary before the knockout stage
However, this situation began to change. With the technological advancement provided by the James Webb Space Telescope (JWST), it is now possible to investigate the beginnings of the universe with unprecedented clarity. Every observation deep into cosmic time has revealed the presence of supermassive black holes. Interestingly, the morphology of galaxies changes drastically as we go back in time. One of JWST’s most notable findings was the identification of hundreds of remote, previously unknown galaxies, nicknamed “little red dots”, characterized by their tiny size, reddish coloration and extreme distance.
Confirming that these structures were, in fact, galaxies required a period of analysis, but now there is a high degree of certainty. Accepting this classification, black holes in their cores stand out for their extraordinary size and extremely fast rotation. Although other enigmas persist, the size of these black holes is the most intriguing factor. In 2024, research indicated that these black holes represented between 20% and 70% of the total mass of their galaxies – a proportion much higher than that of most supermassive black holes in more developed host galaxies, for which there was no convincing explanation.
Once again, the James Webb Space Telescope proved fundamental. Thanks to a happy geometric coincidence that amplified the light from a “little red dot” identified as Abell 2744-QSO1 (or just QS01), astronomers have gained an unprecedented perspective on a galaxy that existed just 700 million years after the Big Bang. This opportunity was crucial to advance the understanding of cosmic evolution. By analyzing the extraordinarily high speed of the gas orbiting the galactic center, it was possible to determine the masses of QS01 and its central black hole – a type of measurement that had never been carried out for a black hole at such a remote time in the universe, before a billion years after the Big Bang. The results revealed that the black hole has approximately 50 million solar masses, while the galaxy in its entirety does not exceed 75 million solar masses.
Given these proportions, only two explanations are viable: the direct collapse of a gas cloud or the existence of a primordial black hole. None of these theories assume that the formation of the galaxy preceded that of the black hole. Thus, for this specific galaxy, the black hole at its center appears to have been the cosmic “egg,” emerging first. The old dilemma seems, at least in this case, to have been resolved.
Naturally, science rarely offers such direct solutions without new questions. The next step is to investigate as many other “little red dots” as possible to see if QS01 represents a typical case, in addition to deepening our understanding of the exact formation process of its black hole and the composition of the rest of the galaxy. These future investigations will undoubtedly bring to light a host of new mysteries. However, it is essential to celebrate this significant achievement, which, for now, allows us to affirm: the “egg” — the black hole — in fact came first.
