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Gravitational Wave Search Finds Tantalizing New Clue: Unexplained Fluctuations in Space-Time – SciTechDaily

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This illustration shows the NANOGrav project observing cosmic objects called pulsars in an effort detect gravitational waves – ripples in the fabric of space. The project is seeking a low-level gravitational wave background signal that is thought to be present throughout the universe. Credit: NANOGrav/T. Klein

An international team of scientists may be close to detecting faint ripples in space-time that fill the universe.

Pairs of black holes billions of times more massive than the Sun may be circling one another, generating ripples in space itself. The North American Nanohertz Observatory for Gravitational Waves (NANOGrav) has spent more than a decade using ground-based radio telescopes to look for evidence of these space-time ripples created by behemoth black holes. This week, the project announced the detection of a signal that may be attributable to gravitational waves, though members aren’t quite ready to claim success.

Gravitational waves were first theorized by Albert Einstein in 1916, but they weren’t directly detected until nearly a century later. Einstein showed that rather than being a rigid backdrop for the universe, space is a flexible fabric that is warped and curved by massive objects and inextricably linked with time. In 2015, a collaboration between the U.S.-based Laser Interferometer Gravitational-wave Observatory (LIGO) and the Virgo interferometer in Europe announced the first direct detection of gravitational waves: They were emanating from two black holes — each with a mass about 30 times greater than the Sun — circling one another and merging.

In a new paper published in the January 2021 issue of the Astrophysical Journal Supplements, the NANOGrav project reports the detection of unexplained fluctuations, consistent with the effects of gravitational waves, in the timing of 47 pulsars spread across the sky and measured over a span of 12 1/2 years.

Pulsars are dense nuggets of material left over after a star explodes as a supernova. As seen from Earth, pulsars appear to blink on and off. In reality, the light comes from two steady beams emanating from opposite sides of the pulsar as it spins, like a lighthouse. If gravitational waves pass between a pulsar and Earth, the subtle stretching and squeezing of space-time would appear to introduce a small deviation in the pulsar’s otherwise regular timing. But this effect is subtle, and more than a dozen other factors are known to influence pulsar timing as well. A major part of the work done by NANOGrav is to subtract those factors from the timing data for each pulsar before looking for signs of gravitational waves.

LIGO and Virgo detect gravitational waves from individual pairs of black holes (or other dense objects called neutron stars). By contrast, NANOGrav is looking for a persistent gravitational wave “background,” or the noiselike combination of waves created over billions of years by countless pairs of supermassive black holes orbiting one another across the universe. These objects produce gravitational waves with much longer wave lengths than those detected by LIGO and Virgo – so long that it might take years for a single wave to pass by a stationary detector. So while LIGO and Virgo can detect thousands of waves per second, NANOGrav’s quest requires years of data.

As tantalizing as the latest finding is, the NANOGrav team isn’t ready to claim they’ve found evidence of a gravitational wave background. Why the hesitation? In order to confirm direct detection of a signature from gravitational waves, NANOGrav’s researchers will have to find a distinctive pattern in the signals between individual pulsars. According to Einstein’s theory of general relativity, the effect of the gravitational wave background should influence the timing of the pulsars slightly differently based on their positions relative to one another.

At this point, the signal is too weak for such a pattern to be distinguishable. Boosting the signal will require NANOGrav to expand its dataset to include more pulsars studied for even longer lengths of time, which will increase the array’s sensitivity. NANOGrav is also pooling its data with those from other pulsar timing array experiments in a joint effort by the International Pulsar Timing Array, a collaboration of researchers using the world’s largest radio telescopes.

“Trying to detect gravitational waves with a pulsar timing array requires patience,” said Scott Ransom with the National Radio Astronomy Observatory and the current chairperson of NANOGrav. “We’re currently analyzing over a dozen years of data, but a definitive detection will likely take a couple more. It’s great that these new results are exactly what we would expect to see as we creep closer to a detection.”

Reference: “The NANOGrav 12.5 yr Data Set: Observations and Narrowband Timing of 47 Millisecond Pulsars” by Md F. Alam , Zaven Arzoumanian, Paul T. Baker, Harsha Blumer, Keith E. Bohler, Adam Brazier, Paul R. Brook, Sarah Burke-Spolaor, Keeisi Caballero, Richard S. Camuccio, Rachel L. Chamberlain, Shami Chatterjee, James M. Cordes, Neil J. Cornish, Fronefield Crawford, H. Thankful Cromartie, Megan E. DeCesar, Paul B. Demorest, Timothy Dolch, Justin A. Ellis, Robert D. Ferdman, Elizabeth C. Ferrara, William Fiore, Emmanuel Fonseca, Yhamil Garcia, Nathan Garver-Daniels, Peter A. Gentile, Deborah C. Good, Jordan A. Gusdorff, Daniel Halmrast, Jeffrey S. Hazboun, Kristina Islo, Ross J. Jennings, Cody Jessup, Megan L. Jones, Andrew R. Kaiser, David L. Kaplan, Luke Zoltan Kelley, Joey Shapiro Key, Michael T. Lam, T. Joseph W. Lazio, Duncan R. Lorimer, Jing Luo, Ryan S. Lynch, Dustin R. Madison, Kaleb Maraccini, Maura A. McLaughlin, Chiara M. F. Mingarelli, Cherry Ng, Benjamin M. X. Nguyen, David J. Nice, Timothy T. Pennucci, Nihan S. Pol, Joshua Ramette, Scott M. Ransom, Paul S. Ray, Brent J. Shapiro-Albert, Xavier Siemens, Joseph Simon, Renée Spiewak, Ingrid H. Stairs, Daniel R. Stinebring, Kevin Stovall, Joseph K. Swiggum, Stephen R. Taylor, Michael Tripepi, Michele Vallisneri, Sarah J. Vigeland, Caitlin A. Witt and Weiwei Zhu (The NANOGrav Collaboration), 21 December 2020, Astrophysical Journal Supplement Series.
DOI: 10.3847/1538-4365/abc6a0

The NANOGrav team discussed their findings at a press conference on January 11, 2021, at the 237th meeting of the American Astronomical Society, held virtually from Jan. 10 to 15. Michele Vallisneri and Joseph Lazio, both astrophysicists at NASA’s Jet Propulsion Laboratory in Southern California, and Zaven Arzoumanian at NASA’s Goddard Space Flight Center in Maryland are co-authors of the paper. Joseph Simon, a researcher at University of Colorado Boulder and the paper’s lead author, conducted much of the analysis for the paper as a postdoctoral researcher at JPL. Multiple NASA postdoctoral fellows have participated in the NANOGrav research while at JPL. NANOGrav is a collaboration of U.S. and Canadian astrophysicists. The data in the new study was collected using the Green Bank antenna in West Virginia and the Arecibo dish in Puerto Rico before its recent collapse.

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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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