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A Black Hole’s Lunch Provides a Treat for Astronomers – The New York Times

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Astronomers announced today that they had discovered something new out in the dark: a stellar corpse too heavy to be a neutron star — the remnant of a supernova explosion — but not heavy enough to be a black hole.

Whatever it once was, it is long gone. About 780 million years ago — and 780 light-years away — it was eaten by a black hole 23 times more massive than the sun. That feast left behind an even heavier black hole — a vast, hungry nothing with the mass of 25 suns.

News of that event only recently reached Earth, in the form of space-time ripples known as gravitational waves. These evanescent vibrations were felt on Aug. 14, 2019, by an array of antennas in Italy and the United States called the International LIGO-Virgo Collaboration, and the results were published on Tuesday in Astrophysical Journal Letters.

According to a theory that has been the backbone of decades of astrophysical excitement, a star can wind up in one of three final states, depending on its mass: a perpetually cooling cinder known as a white dwarf; a dense star, with the mass of a couple of suns compressed into a ball only 12 or so miles wide, known as a neutron star; or a black hole, a beast reluctantly predicted by Albert Einstein to be so dense that nothing, not even light, can escape its gravity.

The victim in this collision weighed in at 2.6 solar masses, according to the LIGO-Virgo calculations. That is heavier than the accepted limit of 2.5 suns for a neutron star. But the lightest black hole ever measured was about five solar masses.

So the mystery object lies squarely in what astrophysicists call the “mass gap.” Astronomers have long wondered what, if anything, could occupy this astronomical no-man’s land.

“We’ve been waiting decades to solve this mystery” Vicky Kalogera of Northwestern University, one of the main authors of the paper, said in an interview. “We don’t know if this object is the heaviest known neutron star or the lightest known black hole, but either way it breaks a record.”

She added: “If it’s a neutron star, it’s an exciting neutron star. If it’s a black hole, it’s an exciting black hole.”

In a statement issued by the Science and Technology Facilities Council in Britain, Charlie Hoy, a graduate student at Cardiff University and Dr. Kalogera’s co-author, said, “I did not believe the alert when I first saw it come through.”

The LIGO observatory made history in 2016 when it detected gravitational waves from a pair of colliding black holes, proving the existence both of gravitational waves, a century after Einstein predicted them, and of black holes. The instrument consists of twin L-shaped antennas in Hanford, Wash., and Livingston, La.

Since then, LIGO has been joined in its exploration of the darkness by another antenna known as Virgo, in Cascina, Italy. The combined LIGO-Virgo Collaboration consists of about 2,000 scientists around the world. The alphabetical listing of their names and institutions takes up the first five and a half pages of the new paper.

The puzzling collision recorded last August was one of 56 possible gravitational wave events — most of which appear to be black hole collisions — detected during the observatory’s third run, which went from April 2019 until March 2020, when the coronavirus pandemic shut down most scientific activities around the world. The collaboration is still reviewing the data in an effort to analyze and confirm them.

Dr. Kalogera said that the event was exciting for several reasons. The ratio of the two colliding masses was the most extreme — nine to one — of the gravitational wave collisions that have been observed so far. Astronomers have difficulty imagining how such unmatched stars could get together in a binary double-star system to begin with.

“This is very hard for formation theories to explain,” she said.

The signal — a characteristic “chirp” caused by the colliding objects circling faster and faster as they approach their moment of ultimate doom — lasted about 10 seconds. “Due to the favorable circumstance of having observed such a loud signal with quite different component masses and for about 10 seconds, we achieved the most precise gravitational-wave measurement of a black hole spin to date,” Alessandra Buonanno, of the Albert Einstein Institute in Potsdam, Germany, said in a statement issued by the institute’s arm in Hannover, Germany.

A black hole’s spin carries important information about the birth and evolution of the black hole, Dr. Buonanno noted. In this case, it revealed that the black hole was spinning “rather slowly,” less than one-tenth the rate allowed by the strictures of Einstein’s theory.

Nobody had any immediate explanation or candidate for what kind of entity could fill this mass gap — a “dearth,” Dr. Kalogera called it — except to affirm that the calculations were robust.

Gordon Baym, an expert on neutron stars at the University of Illinois, pointed out that the collision of a pair of neutron stars in 2017, which produced a cosmic fireworks spectacle, left behind a neutron star with about 2.7 solar masses, thus briefly occupying the mass gap. But that object is thought to have collapsed into a black hole almost immediately.

Most well-measured neutron stars have masses of around 1.4 suns, Dr. Baym said, and only a handful have masses more than two. In theoretical calculations, he said, “it is very hard to make matter stiff enough, using reasonable physics,” to conjure a neutron star in the range of 2.6 solar masses.

Daniel Holz, an astronomy professor at the University of Chicago who is a member of the LIGO collaboration, but not one of the principal authors of this paper, mused that neutron stars and black holes are in some sense “polar opposites.”

“A neutron star is composed of the densest matter in the universe, and is in some sense the ultimate star,” he said in an email. “A black hole is just warped space and time. It doesn’t even have a physical surface! And the interior of a black hole is in some sense not even part of our universe, since nothing can come out of it.”

He added: “What is astounding is that, despite their profound differences, in this particular case we can’t tell which is which!” All the clues disappeared into the resultant black hole.

“So we’re not sure if this object is a neutron star or a black hole, and either way it’s exciting and we learn something new,” Dr. Holz said. “It’s a win-win! Lots of theorists are now sharpening their pencils to try to explain what we’ve seen.”

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The body of a Ugandan Olympic athlete who was set on fire by her partner is received by family

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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.

Kenya’s high rates of violence against women have prompted marches by ordinary citizens in towns and cities this year.

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.

The Canadian Press. All rights reserved.

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The ancient jar smashed by a 4-year-old is back on display at an Israeli museum after repair

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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.”

The Canadian Press. All rights reserved.

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B.C. sets up a panel on bear deaths, will review conservation officer training

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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.

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