Were Scientists Wrong About the Planet Mercury? Its Big Iron Core May Be Due to Magnetism! - SciTechDaily | Canada News Media
Connect with us

Science

Were Scientists Wrong About the Planet Mercury? Its Big Iron Core May Be Due to Magnetism! – SciTechDaily

Published

 on


New research shows the sun’s magnetic field drew iron toward the center of our solar system as the planets formed. That explains why Mercury, which is closest to the sun has a bigger, denser, iron core relative to its outer layers than the other rocky planets like Earth and Mars. Credit: NASA’s Goddard Space Flight Center

New research from the University of Maryland shows that proximity to the sun’s magnetic field determines a planet’s interior composition.

A new study disputes the prevailing hypothesis on why Mercury has a big core relative to its mantle (the layer between a planet’s core and crust). For decades, scientists argued that hit-and-run collisions with other bodies during the formation of our solar system blew away much of Mercury’s rocky mantle and left the big, dense, metal core inside. But new research reveals that collisions are not to blame—the sun’s magnetism is.

William McDonough, a professor of geology at the University of Maryland, and Takashi Yoshizaki from Tohoku University developed a model showing that the density, mass and iron content of a rocky planet’s core are influenced by its distance from the sun’s magnetic field. The paper describing the model was published on July 2, 2021, in the journal Progress in Earth and Planetary Science.

“The four inner planets of our solar system—Mercury, Venus, Earth, and Mars—are made up of different proportions of metal and rock,” McDonough said. “There is a gradient in which the metal content in the core drops off as the planets get farther from the sun. Our paper explains how this happened by showing that the distribution of raw materials in the early forming solar system was controlled by the sun’s magnetic field.”

McDonough previously developed a model for Earth’s composition that is commonly used by planetary scientists to determine the composition of exoplanets. (His seminal paper on this work has been cited more than 8,000 times.)

McDonough’s new model shows that during the early formation of our solar system, when the young sun was surrounded by a swirling cloud of dust and gas, grains of iron were drawn toward the center by the sun’s magnetic field. When the planets began to form from clumps of that dust and gas, planets closer to the sun incorporated more iron into their cores than those farther away.

The researchers found that the density and proportion of iron in a rocky planet’s core correlates with the strength of the magnetic field around the sun during planetary formation. Their new study suggests that magnetism should be factored into future attempts to describe the composition of rocky planets, including those outside our solar system.

The composition of a planet’s core is important for its potential to support life. On Earth, for instance, a molten iron core creates a magnetosphere that protects the planet from cancer-causing cosmic rays. The core also contains the majority of the planet’s phosphorus, which is an important nutrient for sustaining carbon-based life.

Using existing models of planetary formation, McDonough determined the speed at which gas and dust was pulled into the center of our solar system during its formation. He factored in the magnetic field that would have been generated by the sun as it burst into being and calculated how that magnetic field would draw iron through the dust and gas cloud.

As the early solar system began to cool, dust and gas that were not drawn into the sun began to clump together. The clumps closer to the sun would have been exposed to a stronger magnetic field and thus would contain more iron than those farther away from the sun. As the clumps coalesced and cooled into spinning planets, gravitational forces drew the iron into their core.

When McDonough incorporated this model into calculations of planetary formation, it revealed a gradient in metal content and density that corresponds perfectly with what scientists know about the planets in our solar system. Mercury has a metallic core that makes up about three-quarters of its mass. The cores of Earth and Venus are only about one-third of their mass, and Mars, the outermost of the rocky planets, has a small core that is only about one-quarter of its mass.

This new understanding of the role magnetism plays in planetary formation creates a kink in the study of exoplanets, because there is currently no method to determine the magnetic properties of a star from Earth-based observations. Scientists infer the composition of an exoplanet based on the spectrum of light radiated from its sun. Different elements in a star emit radiation in different wavelengths, so measuring those wavelengths reveals what the star, and presumably the planets around it, are made of.

“You can no longer just say, ‘Oh, the composition of a star looks like this, so the planets around it must look like this,’” McDonough said. “Now you have to say, ‘Each planet could have more or less iron based on the magnetic properties of the star in the early growth of the solar system.’”

The next steps in this work will be for scientists to find another planetary system like ours—one with rocky planets spread over wide distances from their central sun. If the density of the planets drops as they radiate out from the sun the way it does in our solar system, researchers could confirm this new theory and infer that a magnetic field influenced planetary formation.

Reference: “Terrestrial planet compositions controlled by accretion disk magnetic field” by William F. McDonough and Takashi Yoshizaki, 2 July 2021, Progress in Earth and Planetary Science.
DOI: 10.1186/s40645-021-00429-4

Adblock test (Why?)



Source link

Continue Reading

News

Here’s how Helene and other storms dumped a whopping 40 trillion gallons of rain on the South

Published

 on

 

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. ”

___

Follow AP’s climate coverage at https://apnews.com/hub/climate

___

Follow Seth Borenstein on Twitter at @borenbears

___

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.

Source link

Continue Reading

Science

‘Big Sam’: Paleontologists unearth giant skull of Pachyrhinosaurus in Alberta

Published

 on

 

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.

Source link

Continue Reading

News

The ancient jar smashed by a 4-year-old is back on display at an Israeli museum after repair

Published

 on

 

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.

Source link

Continue Reading

Trending

Exit mobile version