![\"An](\"https:\/\/cdn.sci.news\/images\/enlarge13\/image_14072e-GW231123.jpg\")
<\/a><\/p>\nAn infographic detailing the GW231123 black hole merger. Image credit: Simona J. Miller \/ Caltech.<\/p>\n
LIGO made history in 2015 when it made the first-ever direct detection of gravitational waves, ripples in space-time.<\/p>\n
In that case, the waves emanated from a black hole merger that resulted in a final black hole 62 times the mass of our Sun.<\/p>\n
The signal was detected jointly by the twin detectors of LIGO, one located in Livingston, Louisiana, and the other in Hanford, Washington.<\/p>\n
Since then, the LIGO team has teamed up with partners at the Virgo detector in Italy and the Kamioka Gravitational Wave Detector (KAGRA) in Japan to form the LVK Collaboration.<\/p>\n
These detectors have collectively observed more than 200 black hole mergers in their fourth run, and about 300 in total since the start of the first run in 2015.<\/p>\n
Before now, the most massive black hole merger \u2014 produced by an event that took place in 2021 called GW190521 \u2014 had a total mass of 140 times that of the Sun.<\/p>\n
In the GW231123 event, the 225-solar-mass black hole was created by the coalescence of black holes each approximately 100 and 140 times the mass of the Sun.<\/p>\n
This puts it in a rare category of black holes called intermediate-mass black holes \u2014 heavier than those formed from stellar collapse, but much lighter than the supermassive black holes that lurk in the centers of galaxies.<\/p>\n
In addition to their high masses, the merging black holes were also rapidly spinning.<\/p>\n
\u201cThis is the most massive black hole binary we\u2019ve observed through gravitational waves, and it presents a real challenge to our understanding of black hole formation,\u201d said Dr. Mark Hannam, an astrophysicist at Cardiff University and a member of the LVK Collaboration.<\/p>\n
\u201cBlack holes this massive are forbidden through standard stellar evolution models.\u201d<\/p>\n
\u201cOne possibility is that the two black holes in this binary formed through earlier mergers of smaller black holes.\u201d<\/p>\n
\u201cThis observation once again demonstrates how gravitational waves are uniquely revealing the fundamental and exotic nature of black holes throughout the Universe,\u201d said Dr. Dave Reitze, executive director of LIGO at Caltech.<\/p>\n