European University Cyprus participates in discovery that links black holes to dark energy

Andreas Efstathiou, Astrophysicist, Rector and Director of the Aristarchus Research Center at European University Cyprus, has been working with University of Hawaii and a team of 17 researchers across nine countries to develop a description of black holes that agrees with observations from the past decade.

According to a press release by the European University Cyprus, searching through existing data spanning nine billion years, the researchers have uncovered the first evidence of ‘cosmological coupling,’ a newly predicted phenomenon in Einstein’s theory of gravity, possible only when black holes are placed inside an evolving universe.

“The question of the nature of Dark Energy is perhaps the most important unanswered question in contemporary physics. It’s 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. It’s very exciting”, Andreas Efstathiou said.

The team has recently published two papers, one in The Astrophysical Journal and the other in The Astrophysical Journal Letters, that studied supermassive black holes at 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 can’t easily be explained by standard galaxy and black hole processes, such as mergers or accretion of gas.

The second paper finds that the growth in mass of these black holes matches predictions for black holes that not only cosmologically couple, but also enclose vacuum energy—material that results from squeezing matter as much as possible without breaking Einstein’s equations, thus avoiding a singularity.

It adds that with singularities removed, the paper then shows that the combined vacuum energy of black holes produced in the deaths of the universe’s first stars agrees with the measured quantity of dark energy in our universe.

These new measurements, it says, if supported by further evidence, redefine our understanding of what a black hole is.

The researchers say their studies provide a framework for theoretical physicists and astronomers to further test – and for the current generation of dark energy experiments such as the Dark Energy Spectroscopic Instrument and the Dark Energy Surve – to shed light on the idea.

Source: Cyprus News Agency