British scientists have discovered what could very well be the source of dark energy that keeps the universe expanding. This involves a type of supermassive black hole lurking in galaxies that contains Earth.
According to Live Science, by comparing supermassive black holes over the 9 billion years of cosmic history, astronomers have found clues suggesting that they may be the origin of a mysterious force that accounts for 68% of the universe, known as dark energy. This dark energy drives our universe to continue expanding rapidly, even 13.8 billion years after the Big Bang.
The supermassive black holes in question are a type of black hole hidden at the center of large galaxies, with Sagittarius A* at the center of the Milky Way Galaxy being one prominent example.
Graphic depiction of a supermassive black hole – (Image: SHANGHAI ASTRONOMICAL OBSERVATORY).
“If the theory is correct, this will revolutionize cosmology, as we finally have an explanation for the origin of dark energy that has puzzled astronomers and theoretical physicists for over 20 years” said co-author Chris Pearson from the Rutherford Appleton Laboratory (RAL – UK).
This research aims to unravel a phenomenon proven over the past century: the universe is currently expanding at a faster rate than ever before, contrary to predictions of a “big crunch” that would counteract the Big Bang, causing the universe to gradually contract.
“Big Crunch” is a hypothetical scenario driven by gravitational forces—something that is universally present in the cosmos—causing the universe to eventually collapse in on itself over time. Thus, something must be strong enough to counteract gravity, pushing the components of the universe further apart.
This mysterious force is termed dark energy, but for many years, scientists have struggled to explain exactly what it is.
For dark energy to effectively counteract the universe’s contraction, it must be extremely prevalent.
Two independent research teams have been working together to uncover clues by comparing the masses of central black holes belonging to two different groups of galaxies: one group that is young and distant, about 9 billion light-years away, and another group that is closer and older.
The results indicate that in the universe, the supermassive black holes in these galaxies have recently expanded 7 to 20 times compared to the black holes from the early universe, a bizarre development that cannot be explained merely by the merger of black holes.
From this, researchers suggest that black holes must grow in tandem with the universe. They consume stars at their centers using dark energy and continue to expand, pushing the entire universe to grow along with them.
According to co-author Dave Clement from the Royal Holloway University of London, they may have found answers to one of the biggest questions in cosmology.
The findings were recently published in two papers in The Astrophysical Journal and The Astrophysical Journal Letters.
