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Astronomers detect most massive black hole collision to date
A collision observed between two black holes, each more massive than a hundred suns, is the largest merger of its kind ever recorded, according to new research.
A team of astronomers discovered the event, dubbed GW231123, parimatch app india when the Laser Interferometer Gravitational-Wave Observatory (LIGO) — a pair of identical instruments located in Livingston, Louisiana, and Hanford, Washington — detected faint ripples in space-time produced by two black holes slamming into each other. Physicists call such ripples gravitational waves.
Gravitational waves were predicted by Albert Einstein in 1915 as part of his theory of relativity, but he thought they were too weak to ever be discovered by human technology. In 2016, however, LIGO detected them for the very first time when black holes collided, proving Einstein right (once again). The following year, three scientists received awards for their key contributions to the development of what has been colloquially called a “black hole telescope.”
Since the first detection of gravitational waves, LIGO and its sister instruments — Virgo in Italy, and KAGRA in Japan — have picked up signs of about 300 black hole mergers. “These amazing detectors are really the most sensitive measuring instruments that human beings have ever built,” said Mark Hannam, head of Gravity Exploration Institute at Cardiff University in the UK and a member of the LIGO Scientific Collaboration. “So, we’re observing the most violent and extreme events in the universe through the smallest measurements we can make.”
The Laser Interferometer Gravitational-wave Observatory (LIGO) in Livingston, Louisiana, is one of two identical instruments that astronomers have used to make the observation.
The Laser Interferometer Gravitational-wave Observatory (LIGO) in Livingston, Louisiana, is one of two identical instruments that astronomers have used to make the observation. Xinhua/Shutterstock
GW231123, however, is exceptional among those 300 black hole mergers, and not just because it is the most massive of the collisions.
“The individual black holes are special because they lie in a range of masses where we do not expect them to be produced from dying stars,” said Charlie Hoy, a research fellow at the University of Plymouth in the UK who’s also a member of the LIGO Scientific Collaboration. “As if this wasn’t enough,” he continued, “the black holes are also likely spinning almost as fast as physically possible. GW231123 presents a real challenge to our understanding of black hole formation.”
A ‘mass gap’
Gravitational waves are the only way scientists can observe a collision in a binary system in which two black holes orbit each other. “Before we could observe them with gravitational waves, there was even a question of whether black hole binaries even existed,” Hannam said. “Black holes don’t give off any light or any other electromagnetic radiation, so any kind of regular telescope is unable to observe them.”
According to Einstein’s theory of general relativity, gravity is a stretching of space and time, and it forces objects to move through curved space. When objects move very rapidly, like spinning black holes, the curved space forms ripples that spread outward like waves.
These gravitational waves are “ridiculously weak,” according to Hannam, and there are limitations to the information they can provide. For example, there’s uncertainty about the distance of GW231123 from Earth; it could be up to 12 billion light-years away. Hannam is more confident about the mass of the two black holes, which are believed to be approximately 100 and 140 times the mass of the sun.
