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Black hole crashes warp spacetime 1,000 times yearly

Staff writer |
Crashes of black holes similar to the one that triggered the first detection of gravitational waves in September happen about 1,000 times per year.

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They should be detectable with the next-generation of gravitational wave observatories, a new study shows.[break]

The finding stems from an attempt to discover the source of the September 14, 2015, black hole merger that set off vibrations in space and across time.

The detection of so-called gravitational waves, predicted 100 years ago by Albert Einstein, demonstrated a new technique for observing the universe.

In the new study, reported in Nature, Warsaw University astrophysicist Krzysztof Belczynski and colleagues conclude that the pair of black holes, each about 30 times more massive than the sun, probably started off as two behemoth stars that formed about 2 billion years after the Big Bang.

The stars, which were estimated to be between 40 and 100 times more massive than the sun, didn't last long. About 5 million years after forming, they became black holes that orbited one another for another 10.3 billion years.

The pair then merged in crash so violent that it warped the interwoven fabric of space and time, setting off a wave, which 1.2 billion years later was detected by Laser Interferometer Gravitational-Wave Observatory, or LIGO, on Earth.

"The black holes were monsters, and the results show that their progenitor stars would have been some of the brightest and most massive in the universe," physicist J.J. Eldridge, with the University of Auckland in New Zealand, writes in a commentary in this week's Nature.

"If the proposed age of the stars' formation is correct, then they might have contributed to the re-ionization of the universe — one of the key events in the universe's evolution," Eldridge added.

The research is based on very precise numerical simulations of the formation of binary black holes from isolated pairs of binary stars, Belczynski and colleagues write.

The models serve as "a framework within which to interpret the first gravitational-wave source... and to predict the properties of subsequent binary-black-hole gravitational-wave events," the scientists said.

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