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A supernova may have killed the monstrous fish of Earth's Devonian Period – CTV News

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TORONTO —
More than 350 million years ago, Earth was ruled by fish, some up to 10 metres long.

But a mass extinction stretching across millions of years killed up to 80 per cent of all species that existed at that time, bringing an end to the Devonian Period.

Scientists have come up with numerous theories over the years for why this extinction might have occurred, such as volcanic activity, meteorites or rapid global warming.

Now, new research is bringing a new possibility to the forefront: what if a supernova was responsible?

A paper published Tuesday in the Proceedings of the National Academy of Sciences of the United States of America (PNAS) details the brand new theory, and how it could feasibly be proven — or ruled out.

The Devonian Period occurred from roughly 416 million to 358 million years ago. The world looked vastly different then, characterized by two supercontinents, Gondwana and Laurussia, which would eventually combine to form Pangaea.

Part of the Paleozoic Era, the Devonian Period is also called The Age of Fishes, as biodiversity exploded within Earth’s oceans during this time. The ancestors of sharks had their beginning in the Devonian, and a fossilized creature from the Devonian period found in the Canadian Arctic in 2004, called a tiktaalik, is thought to be a “vital link between fish and the first vertebrates to walk on land,” according to National Geographic.

During the Late Devonian period, there was a huge loss of biodiversity that occurred over millions of years. Two extinction pulses, the Kellwasser event and, around 10 million years later, the Hangenberg event, are thought to have finished off the Devonian period for good, leading the planet into the Carboniferous Period.

The Hangenberg Crisis refers to a confluence of events that had a catastrophic effect on the living things of that time. There was a widespread issue with the oceans losing a high percentage of oxygen, called an ocean anoxic event, creating massive dead zones within the seas. There was also a dramatic fall in the sea level around the same time.

According to Tuesday’s paper, recent evidence has suggested that the Hangenberg event at the end of the Devonian was also associated with a depletion of the stratospheric ozone — the layer that filters out dangerous ultraviolet radiation from the Sun.

The new research theorizes that a supernova millions of miles away could have bombarded the planet with ionizing radiation, causing the depletion of the ozone.

A supernova is when a dying star of massive proportions explodes, creating either a neutron star or a black hole in its place, and firing a shock wave of elements, gas and charged particles out into the galaxy.

The researchers believe that if a supernova is responsible, it would have been within around 20 parsecs, or 66 lightyears, of Earth, “somewhat beyond the “kill distance” that would have precipitated a full mass extinction.”

Numerous massive stars capable of producing supernovas live in the Milky Way. A supernova within the distance that researchers have posited would have sent cosmic rays washing over the Earth for around 100,000 years.

“The cosmic ray intensity would be high enough to deplete the ozone layer and induce UV-B damage for thousands of years,” the researchers wrote.

They pointed out that while ozone depletion caused by enhanced convection — one of the other theories surrounding the extinction — is generally geographically limited and episodic, ozone depletion caused by a supernova would be “long lived and global and is therefore much more likely to lead to an extinction event.”

Although ionizing radiation from space is known to be a possible cause of ozone depletion, the research says, this theory has never been applied to this particular mass extinction before.

But is there a way to prove this theory? Researchers say there is, if we inspect the distinct layer of rock in the Earth’s crust that corresponds to the Devonian Period, where fossils and preserved material can allow us to peer into the extinction itself.

If a supernova caused by the core collapse of a massive star was close enough to cause this mass extinction, it would also have peppered supernova “debris” over the Earth as “micron or submicron-sized particles created early after the explosion.”

This would’ve left radioactive isotopes on Earth — distinct versions of chemical elements that are unstable and emit radiation as they decay.

Different radioactive isotopes have different lifespans, meaning “those with lifetimes comparable to the time since the event would provide suitable signatures,” if found within fossils or rock from the Devonian Period.

Researchers speculate that two of the long-lived radioisotopes that could’ve been deposited on Earth — and would be still detectable today — could be samarium-146, and plutonium-244.

The end of the Devonian Period, spurred on by numerous extinction events that severely cut down the level of biodiversity in Earth’s oceans, is still a mystery right now. But if scientists can find these radioisotopes, it may mean that supernovas have played a greater role in our planet’s history and evolution than we ever knew.

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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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