Scientists have strengthened the potential connection between dark energy and black holes. Recent research suggests that as more black holes were born in “little Big Bang reverse replays” within the 14.6 billion-year-old cosmos, the strength of dark energy grew to dominance and continues to alter to today.
Dark energy is the placeholder name given to the mysterious force driving the acceleration of the universe’s expansion in its current epoch. It’s troubling because scientists do not know what dark energy is, yet it dominates our universe, accounting for around 70% of the cosmic matter/energy budget. This wasn’t all the time the case, nevertheless. Prior to the dark energy-dominated epoch, matter and gravity had ruled the universe and had succeeded in slowing its initial Big Bang-driven expansion to a near stop. Dark energy then staged its cosmic coup around 5 billion years ago, “hitting the gas” on the expansion of the universe again. The issue is that nobody knows where it got here from or how that switch from matter to dark energy happened.
To handle this mystery, a team of scientists has been asking themselves where within the modern-day universe is gravity as strong because it was at the start of the universe? The reply is just at the guts of black holes. Thus, the team determined that black holes might be “cosmically coupled” to dark energy.
“In line with the cosmological coupling hypothesis, black holes are coupled to the expanding universe and are crammed with dark energy that grows because the universe expands,” team member Gregory Tarlé, professor of physics on the University of Michigan, told Space.com. “This recent development provides confirming evidence that cosmologically coupled black holes may thoroughly be the dark energy of the universe.”
Tarlé says that this might be because when a black hole forms throughout the death and gravitational collapse of one other black hole, it’s akin to the Big Bang running in reverse. During this process, the matter of the large star that births a black hole would grow to be dark energy during its complete gravitational collapse.
If black holes contain dark energy, the team theorizes that they’ll couple with the material of the universe and drive its accelerating expansion. They do not yet have the small print of this is going on, but they’ve evidence that it indeed happening.
“This recent development provides confirming evidence that cosmologically coupled black holes may thoroughly be the dark energy of the universe,” Tarlé said. “This may be very prone to bring us closer to discovering the true nature of dark energy. Perhaps it should also bring us closer to an understanding of the true nature of black holes.”
The center of the mystery lies at the guts black holes
That is the second time the team has published research specializing in the cosmological coupling between black holes and dark energy.
“The primary study we published in February 2024 showed the impact of the expanding universe on the expansion of supermassive black holes in passively evolving elliptical galaxies,” Tarlé said. “If all black holes grew in this manner, they may collectively account for the density of dark energy within the universe today.”
For this recent investigation, they turned to data from the Dark Energy Spectroscopic Instrument (DESI). Composed of 5,000 robotic eyes mounted on the Mayall telescope on the Kitt Peak National Observatory. DESI surveys tens of tens of millions of galaxies and quasars to construct a 3D map spanning the universe out to a distance of 11 billion light-years.
DESI made waves with its first yr of knowledge from its five-year program by suggesting that the density of dark energy within the universe is changing.
“It is mostly believed that dark energy is a property of space and that it’s, due to this fact, uniform and constant in density. DESI has just provided tantalizing evidence that the dark energy density shouldn’t be constant – that it’s changing in time,” Tarlé said. “This coupling theory provides a possible physical mechanism for this variation.”
The team compared the DESI data in regards to the change in dark energy to the variety of black holes born within the deaths of massive stars across cosmic history. This showed that as more black holes were created, the universe’s content of dark energy increased in lockstep. This means that a connection between dark energy and black holes is at the very least plausible.
By showing the change within the density of dark energy suggested by DESI’s first yr of knowledge, which might be accounted for by black holes produced from heavy stars across the peak of star formation, the team has some experimental validation of their theory.
“Showing how the expansion of dark energy density tracks the production and growth of black holes within the expanding universe is an independent commentary that enhances the commentary of the expansion of black holes with the expansion of the universe,” Tarlé continued.
While the Michigan University researcher and his colleagues aren’t yet ready to clarify how dark energy and dark matter are connected, Tarlè is ready to take a position for Space.com.
“Within the very early universe, when gravity was very strong, a type of dark energy caused the universe to exponentially inflate. Through some unknown process, this energy was transformed into the matter of the universe today,” Tarlè explained. “It’s conceivable that, in the middle of black holes, the one place in the current universe where gravity is as strong because it was during inflation, matter gets transformed into dark energy by the reverse process.”
The great thing about this theory, Tarlè said, is that it not only helps to clarify dark energy and where it emerged from but additionally helps solve a lingering problem in black hole science.
Currently, at the guts of black holes, in theory at the very least, there exists a singularity, some extent where the equations of Einstein’s theory of gravity and general relativity go to infinity and, thus, where all physics breaks down. The cosmological coupling of dark energy and black holes does away with this singularity.
“Our theory has the additional benefit of providing a mechanism where a central singularity could also be avoided,” Tarlè added. “Einstein never believed within the singularity at the middle of black holes and felt that this represented a failure of his theory.”
Tarlé explained that this work could grow down a series of possible avenues. He added that there are numerous “next steps” the team could take. Amongst them is seeing if their results delay when DESI releases its next 3 years of knowledge, which is predicted to drop inside several months.
The researchers may even try and understand the distribution of cosmologically coupled black holes within the universe and work on an “interior solution” for cosmologically coupled black holes.
“Fundamentally, whether black holes are dark energy, coupled to the universe they inhabit, has ceased to be only a theoretical query,” Tarlé concluded. “That is an experimental query now.”
The team’s research was published within the Journal of Cosmology and Astroparticle Physics on Monday (Oct. 28).
