Scientists record largest black hole merger to date

In a groundbreaking observation, gravitational wave detectors have captured the most massive black hole merger recorded to date, compelling astrophysicists to reconsider prevailing theories of black hole formation and evolution. 

This finding, first detailed by Ian Sample in The Guardian, highlights a significant breakthrough in gravitational wave astronomy, Caliber.Az reports.

The Laser Interferometer Gravitational-Wave Observatory (LIGO), operating facilities in Washington and Louisiana, registered the event on 23 November 2023 at approximately 14:00 UK time. The detection revealed a gravitational wave signal from a cataclysmic collision that occurred nearly 10 billion light years from Earth, marking it as both a distant and highly energetic event. 

The colliding black holes were calculated to have masses of 103 and 137 solar masses, respectively—well above the so-called "pair-instability gap," a theoretical mass range in which black holes are not expected to form via conventional stellar collapse mechanisms.

The merged object, formed in the aftermath of the collision, is estimated to be 265 times the mass of the sun. This exceeds the mass of any previously detected post-merger black hole via gravitational wave signals. 

The detection of such massive progenitor black holes within this unexpected mass regime suggests the likelihood of hierarchical mergers—where black holes formed from earlier mergers collide again in dense stellar environments. 

The extreme spin, estimated to be around 400,000 times faster than Earth's rotation, further supports this scenario, as spin is typically amplified during such successive merger processes.

As Professor Mark Hannam of Cardiff University's Gravity Exploration Institute noted, the phenomena captured are “the most violent events we can observe in the universe,” yet the signals that reach Earth are minuscule—on the scale of distortions smaller than a proton's width. These subtle space-time perturbations are only detectable thanks to the extreme sensitivity of interferometric gravitational wave detectors.

This newly documented event raises important questions regarding the formation channels of intermediate-mass black holes, an area still rife with uncertainties. It also pushes against long-held theoretical constraints that predict a void in black hole formation between approximately 60 and 120 solar masses due to pair-instability supernovae disrupting the progenitor stars.

The gravitational wave community has so far cataloged around 300 such merger events since LIGO and its counterparts became operational. However, this particular event—highlighted during the GR-Amaldi conference in Glasgow—represents a new frontier in both observational capacity and theoretical challenge.

The implications of this detection are broad. As gravitational wave observatories increase in sensitivity and number over the next decade, researchers anticipate detecting a greater variety of black hole mergers across the cosmos. These developments are expected not only to fill existing knowledge gaps but also to uncover entirely new classes of astrophysical phenomena.

As Hannam aptly stated, “Usually what happens in science is, when you look at the universe in a different way, you discover things you didn’t expect and your whole picture is transformed.” This merger marks such a transformation—a paradigm-shifting discovery driven by a new lens on the dynamic universe.

By Aghakazim Guliyev