Observations of the most distant quasars have shown that supermassive black holes are one of the main reasons why the universe has started producing far fewer stars than usual in recent times, leading to its noticeable dimming, according to an article published in the journal MNRAS.
In the center of the Milky Way and practically all galaxies there is a supermassive black hole, invisibly "orchestrating" the processes of the circulation of matter throughout the galaxy. For a long time, astronomers believe that the activation of such black holes leads to the gradual devastation of the galaxy and the cessation of star formation processes as a result of the black hole heating up and throwing cold clouds of dust and hydrogen outside the galaxy, inside which stars are born.
More recently, according to Frederick Hamann of the University of California at Riverside (USA), scientists have found the first evidence that this is actually happening, but how this process affects the apparent dimming of the universe over the past billion years remained unknown.
The fact is that last year, astronomers discovered that the universe now produces almost half as much light, heat and other forms of energy as it did two billion years ago. The reasons for this are not yet clear, but most astrophysicists believe that quasars, which suppressed star formation in about half of the visible galaxies, could be involved in this.
Hamann and his colleagues were able to prove that this dimming is due precisely to the activity of quasars by studying the most distant supermassive black holes scientists have found in the framework of the BOSS project. This project is intended to search for "folds" in the distribution of matter in the Universe, which have arisen as a result of the "echo" of the Big Bang. To do this, astronomers study the spectrum of the most ancient light sources and the location of galaxies in the "cosmic web" of the Universe.
Studying the most "red" and distant quasars, the authors of the article discovered in almost all of them one common and unusual feature, which may explain why quasars made the Universe less bright than it was before.
As it turned out, almost two hundred of the most distant quasars have an unusually "flat" and continuous spectrum, indicating that we see them in an almost "naked" form, not covered by a cloud of dust and gas that usually surround many inactive supermassive black holes today … This means that such quasars very actively absorbed matter and constantly "spit out" part of it back, thereby clearing the surrounding space from cold dust and gas, and depriving their galaxies of "stellar building materials".
Naturally, this process could not continue forever, and many galaxies actually "died", completely stopping the formation of new stars due to the activity of such black holes. Scientists believe this explains why the universe is gradually "dying" today.
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