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Dinosaur asteroid's trajectory was 'perfect storm' – BBC News

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A clear picture is emerging of why the asteroid that struck Earth 66 million years ago was so catastrophic.

The space object, which wiped out 75% of all species including the dinosaurs, hit the worst possible place on the planet and – according to new research – at the most lethal angle.

Investigations at the crater site, together with computer simulations, suggest the impactor dug into the crust at an inclination of up to 60 degrees.

This exacerbated the climatic fallout.

We know that the target rocks, in what is now the Gulf of Mexico, contained huge volumes of sulphur from the mineral gypsum. When this material was thrown high into the atmosphere and mixed with water vapour, it produced a “global winter”.

And the angle of attack ensured this environmental crisis was intense and prolonged.

“At 45 to 60 degrees, the impact is very efficient at vaporising and ejecting debris to high altitude. If the impact happens at shallower or much steeper angles, the amount of material that’s put into the atmosphere that can then have climate-changing effects is significantly less,” explained Prof Gareth Collins from Imperial College London.

“It’s evident that the nature of the location where this event happened, together with the impact angle, made for a perfect storm,” he told BBC News.

The majority of plant and animal life on Earth succumbed to the the challenging conditions.

Prof Collins’ and colleagues’ work is published in the journal Nature Communications.

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Prof Collins is part of an international team that’s been studying the anatomy of the crater associated with the calamitous asteroid strike.

Today, this 200km-wide structure is positioned under Mexico’s Yucatan Peninsula, with its best preserved central portions sitting just offshore of the port of Chicxulub.

It’s hard to grasp the scale of the forces that produced it.

The impactor, thought to be about 12km in diameter, punched an instantaneous hole in the crust that was probably some 30km deep. As fluidised rocks at the base of this bowl rebounded, they created in just a few minutes a mountain that was higher than Everest. This didn’t last, however, and it fell back, to leave a prominent inner ring of hills, or peaks.

What’s interesting from Prof Collins’ perspective is the asymmetry that was frozen into the Chicxulub structure.

For example, if you look at the centres of the crater, of its peak ring and of the uplifted rock that underlies the crust in Earth’s mantle – these points do not map directly on top of each other. They’re actually aligned in a northeast-southwest direction, with the crater centre in between the centres of mantle uplift and peak-ring formation.

This is a vital clue in determining not only the direction from which the asteroid arrived but the angle at which it hit the planet.

The Imperial researcher ran a number of simulations on the UK Science and Technology Facilities Council (STFC) DiRAC High Performance Computing Facility. The only way he can reproduce the geometry is by having the asteroid come in from the northeast and strike the Earth at an angle of roughly 60 degrees.

Prof Collins said: “If you run the model at different impact angles, at 30 degrees and at 45 degrees, say, you can’t match the observations – you get centres of mantle uplift and of the peak ring on the downrange side of the crater centre. And for a straight overhead impact, at 90 degrees, the centres are all on top of each other. So, that’s doesn’t match the observations, either.”

Imperial colleague and co-author Prof Joanna Morgan added: “Knowing the direction of impact means we now know which part of the target site was subjected to the greatest shock pressures.

“The sulphur-bearing and carbon-bearing sedimentary rocks actually thicken as you go from east to west, and to the south. So this result means we’re degassing more of those sediments than we would if you just took an average value for their thickness.”

And Prof Sean Gulick from the University of Texas at Austin, US, told BBC News: “This new modelling provides a clear answer to the angle of the impact and the direction of the impact that largely settles a long-standing debate on what was downrange of the impact.

“Also critical is that a 60-degree angle is in the range of the worst options for injecting large volumes of vaporised and ejected sulphur-rich rocks into the atmosphere.

“Thus these results are critical for understanding potential ‘kill mechanisms’,” the co-author explained.

Gulick and Morgan led the expedition that drilled into the Chicxulub Crater in 2016 to recover some of its rocks for an analysis. A follow-up, high-resolution seismic survey is due to take place late this summer that will provide an enhanced 3D view of the structure.


The impact that changed life on Earth

  • Scientists now think a 12km-wide object struck Earth 66 million years ago
  • The crater it produced is about 200km wide and is buried mostly offshore
  • On land, it is covered by limestone, but its rim is traced by an arc of sinkholes
  • Experts drilled into the crater to study its rocks and reconstruct the event
  • They say the impact was more than capable of driving a mass extinction

Jonathan.Amos-INTERNET@bbc.co.uk and follow me on Twitter: @BBCAmos

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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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