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Scientists are getting closer in race to find gravitational wave background and dark matter – Space.com

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Astronomers may be getting closer to discovering as-yet hidden cosmic secrets, such as the nature of dark matter and the presence of widespread distortions in space-time, researchers reported at the 237th American Astronomical Society meeting, held virtually this week.

The existence of dark matter, an the invisible substance thought to make up more than four-fifths of all matter in the universe, may help explain a variety of cosmic puzzles, such as how galaxies can spin as fast as they do without getting ripped apart. However, much about the nature of dark matter — and even whether it exists at all — remains unknown.

To help pinpoint dark matter’s properties, researchers sought to directly measure the gravitational effects that dark matter should have on the speed at which stars are moving in the Milky Way. They focused on galactic lighthouses known as pulsars, or spinning neutron stars that emit twin beams of radio waves from their magnetic poles as they rotate. (Neutron stars are the remains of large stars that perished in catastrophic explosions known as supernovas.)

Related: 8 baffling astronomy mysteries

“It is a very, very small number we are trying to measure,” study lead author Sukanya Chakrabarti, an astrophysicist at the Rochester Institute of Technology in New York, said during a news conference held on Monday (Jan. 11). “In terms of change in velocity, it’s just a few centimeters per second, or roughly the speed of a crawling baby, and not a very fast baby at that.”

Pulsars spin at very steady rates, so they can serve as precise clocks. By monitoring tiny variations in the spin of 14 pulsars, the researchers could estimate the speeds at which these pulsars are moving and thus deduce the gravitational force that dark matter is exerting on them.

The scientists found that across the galaxy, the average amount of dark matter may be slightly lower than previous estimates. The researchers also calculated the amount of dark matter contained within the volume of the Earth is just 1.63 lbs. (740 grams), Chakrabarti said. These findings in turn can help current experiments seeking to directly detect dark matter “try and understand the nature of dark matter particles,” she added. For instance, this might affect how often one might expect such particles to interact with detectors.

In addition, scientists are now analyzing an unusually high number of gamma rays from the center of the Milky Way to see if they might come from annihilating dark matter particles. Previous research suggested dark matter could be made of new kinds of particle, ones that annihilate when they come in contact with each other, generating high-energy gamma rays.

Based on 11 years of data from NASA’s Fermi Gamma-Ray Space Telescope, “we can say what are good candidates for dark matter,” study lead author Mattia di Mauro, an astrophysicist at the National Institute for Nuclear Physics in Torino, Italy, said during the same news conference. These include weakly interacting massive particles, or WIMPS, hypothetical elementary particles that only barely interact with ordinary matter except through their gravitational pull.

“In the future, the Large Hadron Collider or other particle physics detectors could test these specific candidates,” he added.

The gravitational background 

Researchers at the premiere astronomy conference also reported finding the first possible hints of a mysterious new kind of gravitational wave, cosmic ripples that warp the fabric of space and time itself.

Scientists reported the first-ever direct detection of gravitational waves in 2016 using the Laser Interferometer Gravitational-Wave Observatory (LIGO), a discovery that earned the 2017 Nobel Prize in Physics. The space-time distortions those researchers saw were created when two black holes collided with each other about 130 million light-years from Earth. Since then, LIGO has observed dozens more such signals.

But the gravitational waves that LIGO are best at detecting are the most powerful ones, loud outbursts released when extraordinarily massive objects collide with one another. Researchers now also want to detect gravitational waves that are more like the background noise of small talk at a crowded party.

In theory, merging galaxies and other cosmic events should generate such a “gravitational wave background.” Detecting this steady hum could shed light on mysteries such as how galaxies have grown over time.

However, these waves are huge, posing a major challenge for detecting this gravitational wave background. Whereas existing gravitational-wave observatories on Earth are designed to search for gravitational waves on the order of seconds long, ripples from the gravitational wave background are years or even decades long.

Now researchers say they may have detected a strong signal of the gravitational wave background using a U.S. and Canadian project called the North American Nanohertz Observatory for Gravitational Waves (NANOGrav).

“We’re seeing incredibly significant evidence for this signal,” study lead author Joseph Simon, an astrophysicist at the University of Colorado Boulder, said during the AAS press conference. “Unfortunately, we can’t quite say what it is yet.”

NANOGrav uses telescopes on the ground to monitor dozens of pulsars. Gravitational waves can alter the steady blinking pattern of light from pulsars, squeezing and expanding the distances these rays travel through space. 

“As these waves pass us, the Earth gets pushed around very slightly,” Simon said. “As Earth is pushed closer to pulsars in one part of the sky, those pulsars’ pulses will appear a little bit sooner than expected, and pulses from pulsars in the other part of the sky appear to come a bit later.”

Analyzing this pulsar light could therefore help scientists detect signs of the gravitational wave background. 

“By monitoring signals from a large number of these pulsars, we created a galaxy-size gravitational-wave detector within our own Milky Way,” Simon said.

To find these subtle hints, NANOGrav scientists have attempted to observe as many pulsars as they can for as long as possible. So far, they have observed 45 pulsars for at least three years, and in some cases, for more than a dozen years.

“These pulsars are spinning about as fast as your kitchen blender,” Simon said in a statement. “And we’re looking at deviations in their timing of just a few hundred nanoseconds.”

Now the researchers said they have detected potential evidence of a common process distorting the light from many of the pulsars. As of yet, they cannot verify whether this signal is evidence for the gravitational wave background, “but we also don’t have evidence against it,” Simon said.

The scientists caution they still need to look at more pulsars and monitor them for longer time periods to confirm whether the gravitational background is the cause.

If the researchers can verify they have detected the gravitational wave background, they next want to pinpoint what causes these waves and what such signals can tell scientists about the universe.

The scientists detailed their findings Jan. 11 at an online meeting of the American Astronomical Society. Chakrabarti and her colleagues detailed their findings in a study accepted in the journal Astrophysical Journal Letters. Simon and his colleagues detailed their NANOGrav findings online Dec. 24 in the journal The Astrophysical Journal Letters.

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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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