SCIENTISTS have discovered the biggest black hole merger ever recorded, as two massive spacetime ripples spiral into each other.
The monstrous collision occurred on the outskirts of our Milky Way galaxy, and produced a black hole roughly 225 times more massive than the sun.
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Before now, the most massive black hole merger had a total mass of 140 suns.
The new collision event, dubbed GW231123, was found by the LIGO-Virgo-KAGRA (LVK) Collaboration – a group of four detectors that identify cataclysmic cosmic events.
Each black hole was roughly 100 to 140 times the mass of our Sun before they combined.
“This is the most massive black hole binary we’ve observed through gravitational waves, and it presents a real challenge to our understanding of black hole formation,” Mark Hannam, of Cardiff University and a member of the LVK Collaboration, said in a statement.
“Black holes this massive are forbidden through standard stellar evolution models.
“One possibility is that the two black holes in this binary formed through earlier mergers of smaller black holes.”
Evidence of the GW231123 event was discovered in late 2023, when two slight distortions in spacetime were spotted by laser detectors in Louisiana and Washington.
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The signal that arrived at the detectors was coming from two high-mass black holes that were spinning rapidly – meaning they were hard to analyse.
Charlie Hoy, of the University of Portsmouth and also a member of the LVK, explained: “The black holes appear to be spinning very rapidly – near the limit allowed by Einstein’s theory of general relativity.
“That makes the signal difficult to model and interpret.
“It’s an excellent case study for pushing forward the development of our theoretical tools.”
Researchers say they need to observe more similar, high-spin mergers to better calculate just how massive this most recent black hole merger is.
Gregorio Carullo, of the University of Birmingham and a member of the LVK, noted: “It will take years for the community to fully unravel this intricate signal pattern and all its implications.
“Despite the most likely explanation remaining a black hole merger, more complex scenarios could be the key to deciphering its unexpected features.”
The researchers are set to present their findings at the 24th International Conference on General Relativity and Gravitation (GR24) and the 16th Edoardo Amaldi Conference on Gravitational Waves in Glasgow, Scotland this week.
Black holes are formed through the collapse of massive stars or through the merging of smaller black holes.
Known black holes currently fall into just two categories: stellar-mass black holes, which range from a few to a few dozen times the Sun’s mass; and supermassive black holes, which can be anywhere from about 100,000 to 50 billion times as massive as the Sun.
Intermediate-mass black holes fall into the gap of these two mass ranges and are physically unable to form from direct star collapse and are incredibly rare.
Astrophysicists reckon these rare types of black holes grow from merging with others that are similar in size – like our most recent collision event.
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What is a black hole? The key facts
Here’s what you need to know…
- A black hole is a region of space where absolutely nothing can escape
- That’s because they have extremely strong gravitational effects, which means once something goes into a black hole, it can’t come back out
- They get their name because even light can’t escape once it’s been sucked in – which is why a black hole is completely dark
What is an event horizon?
- There has to be a point at which you’re so close to a black hole you can’t escape
- Otherwise, literally everything in the universe would have been sucked into one
- The point at which you can no longer escape from a black hole’s gravitational pull is called the event horizon
- The event horizon varies between different black holes, depending on their mass and size
What is a singularity?
- The gravitational singularity is the very centre of a black hole
- It’s a one-dimensional point that contains an incredibly large mass in an infinitely small space
- At the singularity, space-time curves infinitely, and the gravitational pull is infinitely strong
- Conventional laws of physics stop applying at this point
How are black holes created?
- Most black holes are made when a supergiant star dies
- This happens when stars run out of fuel – like hydrogen – to burn, causing the star to collapse
- When this happens, gravity pulls the centre of the star inwards quickly and collapses into a tiny ball
- It expands and contracts until one final collapse, causing part of the star to collapse inwards thanks to gravity, and the rest of the star to explode outwards
- The remaining central ball is extremely dense, and if it’s especially dense, you get a black hole
