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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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Here’s how Helene and other storms dumped a whopping 40 trillion gallons of rain on the South

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More than 40 trillion gallons of rain drenched the Southeast United States in the last week from Hurricane Helene and a run-of-the-mill rainstorm that sloshed in ahead of it — an unheard of amount of water that has stunned experts.

That’s enough to fill the Dallas Cowboys’ stadium 51,000 times, or Lake Tahoe just once. If it was concentrated just on the state of North Carolina that much water would be 3.5 feet deep (more than 1 meter). It’s enough to fill more than 60 million Olympic-size swimming pools.

“That’s an astronomical amount of precipitation,” said Ed Clark, head of the National Oceanic and Atmospheric Administration’s National Water Center in Tuscaloosa, Alabama. “I have not seen something in my 25 years of working at the weather service that is this geographically large of an extent and the sheer volume of water that fell from the sky.”

The flood damage from the rain is apocalyptic, meteorologists said. More than 100 people are dead, according to officials.

Private meteorologist Ryan Maue, a former NOAA chief scientist, calculated the amount of rain, using precipitation measurements made in 2.5-mile-by-2.5 mile grids as measured by satellites and ground observations. He came up with 40 trillion gallons through Sunday for the eastern United States, with 20 trillion gallons of that hitting just Georgia, Tennessee, the Carolinas and Florida from Hurricane Helene.

Clark did the calculations independently and said the 40 trillion gallon figure (151 trillion liters) is about right and, if anything, conservative. Maue said maybe 1 to 2 trillion more gallons of rain had fallen, much if it in Virginia, since his calculations.

Clark, who spends much of his work on issues of shrinking western water supplies, said to put the amount of rain in perspective, it’s more than twice the combined amount of water stored by two key Colorado River basin reservoirs: Lake Powell and Lake Mead.

Several meteorologists said this was a combination of two, maybe three storm systems. Before Helene struck, rain had fallen heavily for days because a low pressure system had “cut off” from the jet stream — which moves weather systems along west to east — and stalled over the Southeast. That funneled plenty of warm water from the Gulf of Mexico. And a storm that fell just short of named status parked along North Carolina’s Atlantic coast, dumping as much as 20 inches of rain, said North Carolina state climatologist Kathie Dello.

Then add Helene, one of the largest storms in the last couple decades and one that held plenty of rain because it was young and moved fast before it hit the Appalachians, said University of Albany hurricane expert Kristen Corbosiero.

“It was not just a perfect storm, but it was a combination of multiple storms that that led to the enormous amount of rain,” Maue said. “That collected at high elevation, we’re talking 3,000 to 6000 feet. And when you drop trillions of gallons on a mountain, that has to go down.”

The fact that these storms hit the mountains made everything worse, and not just because of runoff. The interaction between the mountains and the storm systems wrings more moisture out of the air, Clark, Maue and Corbosiero said.

North Carolina weather officials said their top measurement total was 31.33 inches in the tiny town of Busick. Mount Mitchell also got more than 2 feet of rainfall.

Before 2017’s Hurricane Harvey, “I said to our colleagues, you know, I never thought in my career that we would measure rainfall in feet,” Clark said. “And after Harvey, Florence, the more isolated events in eastern Kentucky, portions of South Dakota. We’re seeing events year in and year out where we are measuring rainfall in feet.”

Storms are getting wetter as the climate change s, said Corbosiero and Dello. A basic law of physics says the air holds nearly 4% more moisture for every degree Fahrenheit warmer (7% for every degree Celsius) and the world has warmed more than 2 degrees (1.2 degrees Celsius) since pre-industrial times.

Corbosiero said meteorologists are vigorously debating how much of Helene is due to worsening climate change and how much is random.

For Dello, the “fingerprints of climate change” were clear.

“We’ve seen tropical storm impacts in western North Carolina. But these storms are wetter and these storms are warmer. And there would have been a time when a tropical storm would have been heading toward North Carolina and would have caused some rain and some damage, but not apocalyptic destruction. ”

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Follow AP’s climate coverage at https://apnews.com/hub/climate

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Follow Seth Borenstein on Twitter at @borenbears

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Associated Press climate and environmental coverage receives support from several private foundations. See more about AP’s climate initiative here. The AP is solely responsible for all content.

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‘Big Sam’: Paleontologists unearth giant skull of Pachyrhinosaurus in Alberta

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It’s a dinosaur that roamed Alberta’s badlands more than 70 million years ago, sporting a big, bumpy, bony head the size of a baby elephant.

On Wednesday, paleontologists near Grande Prairie pulled its 272-kilogram skull from the ground.

They call it “Big Sam.”

The adult Pachyrhinosaurus is the second plant-eating dinosaur to be unearthed from a dense bonebed belonging to a herd that died together on the edge of a valley that now sits 450 kilometres northwest of Edmonton.

It didn’t die alone.

“We have hundreds of juvenile bones in the bonebed, so we know that there are many babies and some adults among all of the big adults,” Emily Bamforth, a paleontologist with the nearby Philip J. Currie Dinosaur Museum, said in an interview on the way to the dig site.

She described the horned Pachyrhinosaurus as “the smaller, older cousin of the triceratops.”

“This species of dinosaur is endemic to the Grand Prairie area, so it’s found here and nowhere else in the world. They are … kind of about the size of an Indian elephant and a rhino,” she added.

The head alone, she said, is about the size of a baby elephant.

The discovery was a long time coming.

The bonebed was first discovered by a high school teacher out for a walk about 50 years ago. It took the teacher a decade to get anyone from southern Alberta to come to take a look.

“At the time, sort of in the ’70s and ’80s, paleontology in northern Alberta was virtually unknown,” said Bamforth.

When paleontogists eventually got to the site, Bamforth said, they learned “it’s actually one of the densest dinosaur bonebeds in North America.”

“It contains about 100 to 300 bones per square metre,” she said.

Paleontologists have been at the site sporadically ever since, combing through bones belonging to turtles, dinosaurs and lizards. Sixteen years ago, they discovered a large skull of an approximately 30-year-old Pachyrhinosaurus, which is now at the museum.

About a year ago, they found the second adult: Big Sam.

Bamforth said both dinosaurs are believed to have been the elders in the herd.

“Their distinguishing feature is that, instead of having a horn on their nose like a triceratops, they had this big, bony bump called a boss. And they have big, bony bumps over their eyes as well,” she said.

“It makes them look a little strange. It’s the one dinosaur that if you find it, it’s the only possible thing it can be.”

The genders of the two adults are unknown.

Bamforth said the extraction was difficult because Big Sam was intertwined in a cluster of about 300 other bones.

The skull was found upside down, “as if the animal was lying on its back,” but was well preserved, she said.

She said the excavation process involved putting plaster on the skull and wooden planks around if for stability. From there, it was lifted out — very carefully — with a crane, and was to be shipped on a trolley to the museum for study.

“I have extracted skulls in the past. This is probably the biggest one I’ve ever done though,” said Bamforth.

“It’s pretty exciting.”

This report by The Canadian Press was first published Sept. 25, 2024.

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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