A team of international astronomers has caught the merger of two black holes of unprecedented masses creating yet another massive black hole — one that astronomers believed existed in theory but that had never been detected.
The two caught in the act were roughly 85 times and 66 times the mass of the sun (measured as solar masses). After the pair merged — producing a gravitational wave picked up by detectors — they created a black hole 142 times the mass of the sun.
“We’ve never seen something like this before,” said Evan Goetz, a research associate at the University of British Columbia’s physics and astronomy department and co-author of the paper published on Wednesday in the journals Physical Review Letters and Astrophysical Journal Letters.
“This is the first time any type of gravitational signal like this has been measured.”
So far, gravitational waves — ripples in space-time caused by highly energetic processes in space, such as the merging of pairs of black holes or neutron stars or a black hole and a neutron star — typically create a sort of “chirp” noise on the detectors.
This artist’s drawing illustrates a hierarchical scheme for merging black holes. The LIGO and Virgo detectors recently observed a black hole merger with a final mass of 142 times that of the sun, making it the largest of its kind observed in gravitational waves to date. The event is thought to have occurred when two black holes of about 66 and 85 solar masses spiralled into each other and merged. (LIGO/Caltech/MIT/R. Hurt IPAC])
But this one, the researchers say, created more of a short-lived “bang,” producing only about five or six waveforms — which can be thought of as actual waves that oscillate. Comparatively, other gravitational-wave detections have produced hundreds of waveforms.
Due in part to its brief signal, astronomers had to ensure it wasn’t noise that was causing the suspected detection. Now that it has been confirmed, it is the first of its kind — and is shedding light on an elusive member of the black hole family: intermediate-mass black holes.
Surprises abound with discovery
There are two special parts to the findings: one, the sizes of the pair of black holes, particularly the one that is 85 solar masses; and two, the final black hole itself.
Black holes are regions in space where gravity is so strong that nothing can escape them. But they’re not all created equally.
According to theory, stars that are roughly 10 times the mass of the sun can die in a massive explosion — a supernova — that can produce a black hole. Stars that are roughly 65 times more massive are believed to destroy themselves. But stars that are more than 120 solar masses are believed to collapse directly into a black hole at the end of their lives.
So that means black holes between 65 and 120 solar masses shouldn’t even exist. Yet this new discovery contains two that fall within that range. The one that is 85 solar masses is particularly intriguing because it falls right in the middle.
WATCH | Simulation of binary black holes merging:
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Now to the final 142 solar-mass black hole.
There are stellar-mass black holes, which astronomers believe can go up to 10 to 100 times the mass of the sun. Then there are supermassive black holes, which can be found at the centre of most galaxies. These monsters can come in at millions or even billions of times the mass of the sun.
And while there have been theories about those black holes that are 100 solar masses or higher — called intermediate-mass black holes — none have been directly observed.
Until now.
“There’s been no observational evidence prior to this discovery,” Goetz said. “This is the first conclusive evidence for an intermediate-mass black hole.”
Some hypotheses
There are two leading theories as to how these seemingly impossible things have come to be. One is that two stars could have merged to produce a black hole within the 65 to 85 range. The second is that multiple black holes could have merged within a dense star cluster, creating larger black holes of differing masses.
“This is kind of exciting,” said Priya Natarajan, a theoretical astrophysicist and professor of astronomy and physics at Yale University in New Haven, Conn., whose main area of study is black holes. She was not involved with the research.
In a 2014 paper published in the journal Science, Natarajan and her colleague proposed that the creation of black holes similar to the 142 solar-mass one discovered last year could have come within a dense cluster of stars, much in the way the new discovery has been observed (though in her paper, the black hole was larger).
This chart compares the GW190521 merger event to others witnessed by LIGO and Virgo. The black hole created by the merger falls into a category known as an intermediate-mass black hole — and is the first clear detection of a black hole of this type. (LIGO/Caltech/MIT/R. Hurt [IPAC])
“The idea is one of the stars becomes a little black hole, and it starts wandering around and it’s kind of fed by the fire hose of gas [from stars]; it grows very fast,” Natarajan said. “And then it becomes massive, and it grows to about 50 times and then it sinks to the centre.
“The second guy would roll around, but it wouldn’t grow as fast because there wouldn’t be as much gas left over. And so we predict that if you make two in that way, they cannot be the same mass, they will be different … and that’s what is seen now, so that’s kind of exciting.”
While the discovery is a first, the astronomers know that they need to increase their sample size to adequately explain the existence of intermediate-mass black holes.
“We need more observations of this type of signal. So, more mergers that yield intermediate-mass black holes will help us to understand … how they’re formed,” Goetz said. “Black holes play a key role in so many aspects of astrophysics that we’re only just now beginning to understand much more deeply with these observations.”
And more importantly, they will help us understand how we got here, as black holes are key to creating much of what exists.
“It’s part of the origin story of our universe,” Natarajan said. “We may not have been here if our Milky Way did not have black holes.”
NAIROBI, Kenya (AP) — The body of Ugandan Olympic athlete Rebecca Cheptegei — who died after being set on fire by her partner in Kenya — was received Friday by family and anti-femicide crusaders, ahead of her burial a day later.
Cheptegei’s family met with dozens of activists Friday who had marched to the Moi Teaching and Referral Hospital’s morgue in the western city of Eldoret while chanting anti-femicide slogans.
She is the fourth female athlete to have been killed by her partner in Kenya in yet another case of gender-based violence in recent years.
Viola Cheptoo, the founder of Tirop Angels – an organization that was formed in honor of athlete Agnes Tirop, who was stabbed to death in 2021, said stakeholders need to ensure this is the last death of an athlete due to gender-based violence.
“We are here to say that enough is enough, we are tired of burying our sisters due to GBV,” she said.
It was a somber mood at the morgue as athletes and family members viewed Cheptegei’s body which sustained 80% of burns after she was doused with gasoline by her partner Dickson Ndiema. Ndiema sustained 30% burns on his body and later succumbed.
Ndiema and Cheptegei were said to have quarreled over a piece of land that the athlete bought in Kenya, according to a report filed by the local chief.
Cheptegei competed in the women’s marathon at the Paris Olympics less than a month before the attack. She finished in 44th place.
Cheptegei’s father, Joseph, said that the body will make a brief stop at their home in the Endebess area before proceeding to Bukwo in eastern Uganda for a night vigil and burial on Saturday.
“We are in the final part of giving my daughter the last respect,” a visibly distraught Joseph said.
He told reporters last week that Ndiema was stalking and threatening Cheptegei and the family had informed police.
Four in 10 women or an estimated 41% of dating or married Kenyan women have experienced physical or sexual violence perpetrated by their current or most recent partner, according to the Kenya Demographic and Health Survey 2022.
TEL AVIV, Israel (AP) — A rare Bronze-Era jar accidentally smashed by a 4-year-old visiting a museum was back on display Wednesday after restoration experts were able to carefully piece the artifact back together.
Last month, a family from northern Israel was visiting the museum when their youngest son tipped over the jar, which smashed into pieces.
Alex Geller, the boy’s father, said his son — the youngest of three — is exceptionally curious, and that the moment he heard the crash, “please let that not be my child” was the first thought that raced through his head.
The jar has been on display at the Hecht Museum in Haifa for 35 years. It was one of the only containers of its size and from that period still complete when it was discovered.
The Bronze Age jar is one of many artifacts exhibited out in the open, part of the Hecht Museum’s vision of letting visitors explore history without glass barriers, said Inbal Rivlin, the director of the museum, which is associated with Haifa University in northern Israel.
It was likely used to hold wine or oil, and dates back to between 2200 and 1500 B.C.
Rivlin and the museum decided to turn the moment, which captured international attention, into a teaching moment, inviting the Geller family back for a special visit and hands-on activity to illustrate the restoration process.
Rivlin added that the incident provided a welcome distraction from the ongoing war in Gaza. “Well, he’s just a kid. So I think that somehow it touches the heart of the people in Israel and around the world,“ said Rivlin.
Roee Shafir, a restoration expert at the museum, said the repairs would be fairly simple, as the pieces were from a single, complete jar. Archaeologists often face the more daunting task of sifting through piles of shards from multiple objects and trying to piece them together.
Experts used 3D technology, hi-resolution videos, and special glue to painstakingly reconstruct the large jar.
Less than two weeks after it broke, the jar went back on display at the museum. The gluing process left small hairline cracks, and a few pieces are missing, but the jar’s impressive size remains.
The only noticeable difference in the exhibit was a new sign reading “please don’t touch.”
VICTORIA – The British Columbia government is partnering with a bear welfare group to reduce the number of bears being euthanized in the province.
Nicholas Scapillati, executive director of Grizzly Bear Foundation, said Monday that it comes after months-long discussions with the province on how to protect bears, with the goal to give the animals a “better and second chance at life in the wild.”
Scapillati said what’s exciting about the project is that the government is open to working with outside experts and the public.
“So, they’ll be working through Indigenous knowledge and scientific understanding, bringing in the latest techniques and training expertise from leading experts,” he said in an interview.
B.C. government data show conservation officers destroyed 603 black bears and 23 grizzly bears in 2023, while 154 black bears were killed by officers in the first six months of this year.
Scapillati said the group will publish a report with recommendations by next spring, while an independent oversight committee will be set up to review all bear encounters with conservation officers to provide advice to the government.
Environment Minister George Heyman said in a statement that they are looking for new ways to ensure conservation officers “have the trust of the communities they serve,” and the panel will make recommendations to enhance officer training and improve policies.
Lesley Fox, with the wildlife protection group The Fur-Bearers, said they’ve been calling for such a committee for decades.
“This move demonstrates the government is listening,” said Fox. “I suspect, because of the impending election, their listening skills are potentially a little sharper than they normally are.”
Fox said the partnership came from “a place of long frustration” as provincial conservation officers kill more than 500 black bears every year on average, and the public is “no longer tolerating this kind of approach.”
“I think that the conservation officer service and the B.C. government are aware they need to change, and certainly the public has been asking for it,” said Fox.
Fox said there’s a lot of optimism about the new partnership, but, as with any government, there will likely be a lot of red tape to get through.
“I think speed is going to be important, whether or not the committee has the ability to make change and make change relatively quickly without having to study an issue to death, ” said Fox.
This report by The Canadian Press was first published Sept. 9, 2024.
