Cosmological coupling — a newly-predicted phenomenon in Albert Einstein’s theory of gravity — allows black holes to grow in mass without consuming gas or stars, according to a team of astrophysicists from the University of Hawai’i at Mānoa and elsewhere.
“We’re really saying two things at once: that there’s evidence the typical black hole solutions don’t work for you on a long, long timescale, and we have the first proposed astrophysical source for dark energy,” said Dr. Duncan Farrah, an astrophysicist at the University of Hawai’i at Mānoa and lead author of two new studies.
“What that means, though, is not that other people haven’t proposed sources for dark energy, but this is the first observational paper where we’re not adding anything new to the Universe as a source for dark energy: black holes in Einstein’s theory of gravity are the dark energy.”
“These new measurements, if supported by further evidence, will redefine our understanding of what a black hole is.”
In their first study, published in the Astrophysical Journal, Dr. Farrah and colleagues determined how to use existing measurements of black holes to search for cosmological coupling.
Black holes are also hard to observe over long timescales. Observations can be made over a few seconds, or tens of years at most — not enough time to detect how a black hole might change throughout the lifetime of the Universe. To see how black holes change over a scale of billions of years is a bigger task.
“You would have to identify a population of black holes and identify their distribution of mass billions of years ago,” said Dr. Gregory Tarlé, a physicist at University of Michigan.
“Then you would have to see the same population, or an ancestrally connected population, at present day and again be able to measure their mass. That’s a really difficult thing to do.”
Because galaxies can have life spans of billions of years, and most galaxies contain a supermassive…
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