Illustration of black hole merger
Shutterstock / Jurik Peter
New records for black holes have transformed our understanding of the universe’s most extreme entities.
The Laser Interferometer Gravitational-Wave Observatory (LIGO) began its groundbreaking detection of gravitational waves—ripples in the fabric of spacetime—ten years ago, unveiling nearly 100 black hole collisions. On November 23, 2023, Rigo announced receiving a signal described as “an extraordinary interpretation that defies explanation.” According to Sophie Binnie from the California Institute of Technology, her team ultimately concluded that it corresponded to the largest black hole merger ever recorded.
One of the merging black holes was approximately 100 times the mass of the sun, while the other neared 140 solar masses. Previous records featured black holes that were almost half as massive, primarily due to earlier mergers. Team member Mark Hannam from Cardiff University, UK, emphasized that these black holes were not only immense but also spinning at such high speeds that they challenged mathematical models of the universe regarding their formation.
According to Hannam, the masses of these black holes exceed those typically formed from the collapse of aging stars, suggesting they likely resulted from earlier mergers between smaller black holes. “It’s possible that multiple mergers have occurred,” he notes.
“A decade ago, we were astonished to find black holes around 30 solar masses. Now, we observe black holes over 100 solar masses,” adds Davide Gerosa from the University of Bicocca in Milan, Italy. He mentions that gravitational wave signals from these large, quickly rotating black holes are shorter and consequently more challenging to detect. Binnie presented her findings at the Edoardo Amaldi Conference on Gravitational Waves in Glasgow, England, on July 14.
Both Hannam and Binnie emphasize that future observations of similarly remarkable mergers are essential to further decipher these new signals, including unraveling the origins of black holes. As upgrades progress, LIGO is expected to detect more cosmic record-breakers. Yet, in May, the Trump administration proposed halving resources at the facility, which, in Hannam’s opinion, could render capturing new signals exceedingly difficult.
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Source: www.newscientist.com
