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European University in black hole discovery

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The European University of Cyprus was involved in a radical discovery that black holes are linked to dark energy and driving the universe’s expansion.

According to observations of ancient, dormant galaxies with black holes at their centre, massive black holes could be the source of dark energy and expansion.

The laws of physics suggest that gravity should cause the universe to contract, but a mysterious force, which physicists call dark energy, seems to be counteracting this and making the universe expand at an accelerating rate.

One possible explanation is that the source of this dark energy is black holes, but there is scepticism about the hard evidence to support this idea conclusively.

The radical claim comes from an international team who compared the growth rates of black holes in different galaxies.

Andreas Efstathiou, Astrophysicist and Director of the Aristarchus Research Centre at the European University, is working with the University of Hawaii and a team of 17 researchers in nine countries to develop a description of black holes that is consistent with observations over the past decade.

By searching nine billion years of existing data, the researchers discovered the first evidence of “cosmological coupling,” a newly predicted phenomenon in Einstein’s theory of gravity that is only possible when black holes are placed inside an evolving universe.

The team recently published two papers, one in The Astrophysical Journal and the other in The Astrophysical Journal Letters, which studied supermassive black holes in the hearts of ancient and dormant galaxies.

The first paper found that these black holes gain mass over billions of years in a way that the standard galaxy and black hole processes, such as mergers or gas accretion, cannot easily explain.

The second paper found that mass accretion of these black holes matches predictions for black holes that not only couple cosmologically but also contain vacuum energy – material that results from compressing matter as much as possible without violating Einstein’s equations.

Efstathiou said: “the question of the nature of dark energy is perhaps the most important unanswered question in modern physics.

“It is the majority, 70% of the energy of the universe.

“And now we finally have observational evidence of where it comes from, why 70%, and why it’s here now.”

Instead of dark energy being scattered across spacetime, as many physicists have assumed, the scientists suggest that it is created and remains inside black holes, which form in the crushing forces of collapsing stars.

If the scientists are correct, they will have solved the puzzle of the origins, if not the nature, of one of the most mysterious forces in the universe.

Among many questions remaining is how black holes can pull everything nearby towards them while simultaneously driving the universe apart.