New study suggests black holes may be sources of dark energy driving universe's expansion

In a groundbreaking new study published in the journal Cosmology and Astrophysical Particle Physics, researchers from the University of Michigan and Arizona State University have proposed a profound connection between dark energy and black holes, suggesting that black holes could be sources of dark energy influencing cosmic evolution. The study introduces the concept of "cosmological coupling," a new idea that suggests black holes are not only passive objects but might play an active role in dark energy interactions.

Astrophysicist Kevin Croker of Arizona State University and his colleagues investigated the link between black holes and dark energy at the time of black hole formation. "If black holes contain dark energy, they can couple to and grow with the expanding universe, causing its growth to accelerate," Croker explained. "We can't get the details of how this is happening, but we can see evidence that it is happening," he added.

The research team utilized the Dark Energy Spectroscopic Instrument (DESI) mounted on the Nicholas U. Mayall 4-meter Telescope in Arizona to search for evidence of dark energy from black holes. Equipped with 5,000 robotic sensors designed to scan the skies for dark energy, DESI provided precise measurements, enabling researchers to calculate the universe’s expansion rate with remarkable accuracy, consistent with current measurements.

By analyzing data throughout the age of the universe, the team estimated the amount of dark energy and found a match between the increasing density of dark energy and the growing mass of black holes as the universe aged. This provided a compelling clue supporting the idea of what dark energy is. "The two phenomena were consistent with each other—as new black holes were made in the deaths of massive stars, the amount of dark energy in the universe increased in the right way," noted Duncan Farrah, a co-author of the study. "This makes it more plausible that black holes are the source of dark energy."

Physicist Gregory Tarlé of the University of Michigan offered further insight into the findings. "If you ask yourself the question, 'Where in the later Universe do we see gravity as strong as it was at the beginning of the Universe?' the answer is at the center of black holes," Tarlé explained. He described the process as "reverse inflation," where the collapse of a massive star could generate dark energy, acting like the Big Bang reversed. Tarlé emphasized, "Fundamentally, whether black holes are dark energy, coupled to the universe they inhabit, has ceased to be just a theoretical question. This is an experimental question now."

The study found that black holes formed from the collapse of massive stars may contribute to dark energy as they grow. By comparing the black hole formation rate with the expansion of the universe, the researchers observed that as more black holes form, the amount of dark energy increases in a manner consistent with observations of the universe's accelerating expansion. This suggests that black holes could be sources of dark energy linked to the expansion of the universe.

The concept of cosmological coupling emerged from attempts to resolve black hole weirdness with interpretations of general relativity. Any growth demonstrated by black holes in galaxies that have stopped forming new stars could not be attributed to normal growth mechanisms but to cosmological coupling. The research team found signs of growth in the black holes of these "dead" galaxies, which they felt validated their idea of cosmological coupling.

"If the hypothesis that black holes are related to dark energy is proven correct, it would revolutionize conventional knowledge about black holes and dark energy," the researchers stated. The potential implications of this study extend to solving the Hubble tension, a problem in cosmology where different parts of the universe appear to be expanding at different speeds, creating contradictions in current models. The concept suggests that black holes could influence these contradictions.

Despite the promising evidence, the team emphasizes that further research using tools like DESI will be necessary to confirm these initial observations. "Researchers hope that similar observations with tools such as DESI will further improve this knowledge in the future," they noted. "Scientists have not provided enough evidence to support the hypothesis that black holes have something to do with dark energy."

The research offers solutions to several outstanding questions about dark energy and the universe's expansion, representing a new chapter in our understanding of black holes and the forces that shape the universe. As Tarlé concluded, "Fundamentally, whether black holes are dark energy, coupled to the universe they inhabit, has ceased to be just a theoretical question. This is an experimental question now."

Sources: News18, ScienceAlert, Al Youm Al Saba

This article was written in collaboration with generative AI company Alchemiq