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Galactic flash points to long-sought source for enigmatic radio bursts – Science Magazine

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Magnetars are neutron stars with magnetic fields 100 million times stronger than that of any magnet on Earth.

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On 28 April, as Earth’s rotation swept a Canadian radio telescope across the sky, it watched for mysterious millisecondslong flashes called fast radio bursts (FRBs). At 7:34 a.m. local time an enormous one appeared, but awkwardly, in the peripheral vision of the scope. “It was way off the edge of the telescope,” says Paul Scholz, an astronomer at the University of Toronto and a member of the Canadian Hydrogen Intensity Mapping Experiment (CHIME). Because of its brightness, the team knew its source was nearby. All other FRBs seen so far have erupted in distant galaxies—too far and too fast to figure out what produced them.

The team had a hunch about this one. In previous days, orbiting telescopes had witnessed a Milky Way magnetar—a neutron star with a powerful magnetic field—flinging out bursts of x-rays and gamma rays. The turmoil suggested it might be pulsing with radio waves, too. After some extra data processing, the team determined the FRB was “definitely colocated” with the magnetar, Scholz says. “We were really excited.”

The find, announced in a paper posted to the arXiv preprint server on 20 May, could be the missing link in a problem that has puzzled astronomers for more than a decade. It’s only a single event and many questions remain, including why this burst was 30 times less energetic than the weakest FRB traced to another galaxy. Yet astronomers are increasingly confident that some, if not all, of these laserlike radio flashes originate from magnetars, collapsed stars with magnetic fields 100 million times stronger than any magnet made on Earth. A magnetar origin would rule out more exotic sources such as supermassive black holes and merging neutron stars. “The game of alternative theories is becoming more and more difficult,” says theorist Maxim Lyutikov of Purdue University. “For the majority, it’s a decided question: It’s magnetars.”

The first FRB was detected in 2007, and astronomers have tallied a little over 100 since then. Their brevity makes them hard to study or trace to a particular celestial object. But several FRBs have been found to repeat, giving astronomers a chance to identify their host galaxy. And in the past year or two, wide-field telescopes such as CHIME, designed to survey large swaths of the sky, have begun to boost the number of detections substantially.

Another wide-field telescope, the Survey for Transient Astronomical Radio Emission 2—three radio antennas scattered across the western United States—also spotted the 28 April burst and measured its energy, according to a second preprint, posted to arXiv on 21 May. Deepening the mystery, its proposed source, a magnetar called SGR 1935+2154, is “nothing special,” Lyutikov says. Only five of the 30 known magnetars in the Milky Way have been seen to emit weak radio signals, and SGR 1935+2154 is not one of them.

Yet theorists are already jostling to explain how a magnetar could power an FRB. Brian Metzger of Columbia University and colleagues had earlier proposed a model in which magnetars emit frequent bursts of near–light-speed particles, akin to the great puffs of plasma the Sun belches in coronal mass ejections. When a burst slams into material emitted earlier, it creates a shock wave that causes electrons to spiral around magnetic field lines, generating a powerful laserlike radio pulse. Metzger’s group had not applied its model to something as weak as SGR 1935+2154, but when it did, “it worked OK,” he says. The team’s model, Metzger says, can also explain why the magnetar’s x-ray pulse was 100,000 times more energetic than its radio one.

Lyutikov believes the action occurs much closer, near the magnetar’s surface. In 2002—years before the discovery of the first FRBs—he proposed an engine based on magnetic reconnection, in which field lines break and reconnect in new configurations. On the surface of the Sun, the phenomenon drives powerful flares. On a neutron star, Lyutikov says, it could generate the nearly simultaneous bursts of both x-rays and radio waves seen from SGR 1935+2154, although it does not yet account for the laserlike beaming.

“Pretty much every modeler who had previously considered how magnetars could generate an FRB has now said, within days, that they are right,” says Victoria Kaspi, an astronomer at McGill University and a CHIME leader. “They can’t all be right.”

Observers are now training their telescopes toward nearby galaxies hoping to catch more flyweight FRBs. Although the 28 April flash was puny compared with most extragalactic FRBs, it does at least show that magnetars are capable of something more dramatic than their usual feeble radio signals. “This goes a long way to bridging that gap,” says Jason Hessels of the University of Amsterdam. “It all seems a lot more plausible now.”

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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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