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Scientists Finally Confirm A Big Theory About Solar System Formation

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a swirling disk of material

Stars, planets, and black holes all grow by consuming material from the center of a spinning disk. Researchers assumed they knew how material fell into the center, but hadn’t tested the theory until now. (Credit: Michael Owen and John Blondin, NCSU)

Planets, stars, and black holes all grow by consuming material from a spinning disk. While these disks may differ in size, they’re all mostly dependent on the mighty force of gravity, which keeps them spinning around the central mass. Gravity lets small clumps grow into bigger clumps. But it’s not enough to pull the whole disk into the middle in one giant clump, because angular momentum is pulling those clumps away from the center as they spin.

That’s a good thing, because it means that the universe is composed of more than just large, lonely clumps of matter — it’s also why the Earth spins around the sun instead of falling in and burning up. But that kind of central accumulation sometimes happens nonetheless, which is why we see things like planets, stars, and active black holes in the universe around us. Something seemed to be missing from the basic angular momentum vs. gravity theory.

Researchers have had an idea for a while now, but no one had ever tested it until now. The key is that these spinning disks of material also carry an electric charge. And since they’re in motion, that means they’re generating a magnetic field. The turbulent motion of many small objects in that magnetic field leads to instabilities, and the objects begin trading angular momentum: some lose it and fall closer into the center, while others gain it and slide farther out.

Researchers at Princeton’s Plasma Physics Laboratory came up with a way to test this basic principle, called magnetorotational instability, or MRI . They published their results January 14 in the journal Communications Physics. Eric Blackman, a co-author on the paper, said the inspiration for their experiment was based on how most textbooks teach the phenomenon of MRI.

Rocks and Springs

People have assumed for a long time that MRI will make disks of material spread out, pushing close material closer to the center, where it can fall into a central star or black hole, and outer material farther away.

Looking for evidence of MRI in space is tricky. Researchers can see the results of material piling into the center of a system – a star is born, or a black hole shoots out active jets. But measuring the flow of material accurately enough to test MRI is beyond our current abilities.

In labs, the closest analog to a giant spinning disk of charged plasma and dust would be a swirling tank of liquid metal, but that’s also difficult to measure – not to mention expensive and occasionally hazardous. So Blackman and his colleagues took the simplest approach, with springs instead of magnetic fields and weights instead of clouds of charged materials. They filled concentric rotating cylinders with water, and attached a weighted ball with a spring to the center. By spinning the cylinders, they could reproduce the effects of MRI.

a water-filled tank

The Princeton experiment used water-filled cylinders, a spring and a ball as an analogy to MRI. (Credit: Eric Edlund and Elle Starkman)

It’s a simple enough analog, but one that no one had bothered trying before. And it turns out that MRI works just as researchers have long predicted, pushing close materials in and farther materials out. “No matter how much we think something is true and how plausible it sounds,” Blackman says, “When you can test it, that makes it more robust.”

This result may not be surprising, and it may not change how astronomers understand star and planet formation. But it is the most fundamental function of science: proving by experiment something that people up until now have only believed to be true.



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Pumped Milk Gives Infants Different Bacteria Than Breastfeeding, Study Says

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baby feeding milk bottle

(Credit: Africa Studio/Shutterstock)

Mother’s milk provides sustenance for babies. Now researchers find pumped breast milk exposes newborns to more disease-causing bacteria than milk directly from the breast. The discovery suggests breastfeeding practices could shift the makeup of microorganisms in breast milk and infants’ digestive systems.

“We were surprised that the method of feeding was the most consistent factor associated with milk microbiota composition,” said Meghan Azad, a medical geneticist at the Children’s Hospital Research Institute of Manitoba in Canada, who led the new research.

Mighty Milk

Once considered sterile, researchers now know breast milk is full of bacteria. The microbes are thought to help set up infants’ digestive tracts with an ecosystem of microorganisms that will aid the growing human’s digestive and immune systems. Azad and her team were initially curious about this collection of bacteria in infants known as the infant gut microbiome. In an earlier study, they found breastfeeding affected babies’ gut bacteria the most. So, in the new research, the scientists probed the microbes in breast milk.

The researchers checked out the microbes in breast milk from nearly 400 nursing mothers and their three to four month old babies. The mommy-baby pairs are a part of a Canadian Healthy Infant Longitudinal Development birth cohort study known as the CHILD study, a long-term project looking to find the source of pediatric allergies. The researchers also looked at other elements — maternal age, smoking status and the microbes in babies mouths, to name a few — that could affect what bacteria are in breast milk.

Pumping Problem

The microbes in breast milk varied drastically between mothers, the researchers found, and both mom and baby mold the milk microbiome.

“Our results suggest that the infant’s oral bacteria are important in shaping the milk microbiota,” said Shirin Moossavi, a medical microbiology student in Azad’s lab, who authored the research.

But the biggest factor was whether babies received breast milk straight from the nipple or from a bottle. A family of bacteria that includes E. coli and salmonella were more abundant in pumped breast milk than direct breast milk, the researchers reported Wednesday in the journal Cell Host & Microbe.

“It is only in recent years that we have started to understand that there might be differences between direct nursing compared to feeding pumped milk,” Azad said.

“In the future, when we understand the mechanisms better, we might be able to provide recommendations about pump apparatus cleaning and milk storage to minimize the impact on the milk microbiota,” Moossavi added.

But no matter the delivery mode, “overall, breast milk is the best for the infant,” the researchers said.



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NASA Wants to Return to the Moon as Early as This Year

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NASA has big plans for returning to the moon, but private companies will do much of the work. (Credit: NASA)

In November, NASA tapped nine private spaceflight companies who will be allowed to bid on upcoming projects. Yesterday, they elaborated on what those projects would be during an industry forum. Starting as early as this year, NASA hopes to send commercial landers to the lunar surface as the first step toward returning to the moon, this time for good.

Long Lunar To-Do List

There’s a lot of work to be done before permanent or long-term lunar activities can begin. The first tasks will be to practice launching and landing on the moon, as well as answering questions about its surface. There’s plenty of technology NASA wants to see established on the ground before humans are sent back to the moon – and a lot of it is meant to stand in for future Mars settlement as well.

Some of that technology has to do with a recent buzzword among the space settlement community: in-situ resource utilization, or ISRU. This means using materials and resources already available on the moon and, one day, Mars, rather than carting all our resources with us, as has been standard for space missions. This most commonly means using solar power for energy. On the moon, it will also mean extracting water, which can be used for drinking or to power rockets. Both the hydrogen and oxygen that make up water are powerful fuel materials.

So commercial lunar partners will work on how to mine and recycle resources on the moon and make them available for future mission use. They will test habitation for future crewed missions. They’ll prove that they can collect materials from the lunar surface and return them to space or Earth. And they’ll establish communication networks between robots on the moon’s surface, way stations in lunar orbit, and mission control on Earth.

All these commercial endeavors would also need to integrate with NASA’s planned Lunar Gateway. This would be a space station in orbit around the moon that would serve as Grand Central Station for robotic or crewed missions to the lunar surface, or even for deep space missions. NASA hopes to open the Gateway by 2026, with the first power and propulsion elements entering orbit in 2022.



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Climate Change Hearings Signal Congress Is Willing to Address the Issue Again

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(credit: Roschetzky Photography/Shutterstock)

Climate change is real. It’s happening now. And it presents significant problems for the U.S. across multiple facets of society, according to a panel of climate and policy experts that testified before the House Science, Space and Technology Committee Wednesday in Washington, D.C.

The testimonials were part of the House Science Committee’s first full hearing of the 116th Congress and one of only a handful in the last eight years to address climate change. But that’s about to change. In her opening remarks, House Science Committee Chairwoman Eddie Bernice Johnson (D-TX) said Wednesday’s hearing will be the first of multiple hearings on climate change in the near future.

“Climate change is not just an environmental challenge,” said Robert Kopp, a climate scientist at Rutgers University in New Brunswick, New Jersey, during his testimony. “It’s an economic challenge, an infrastructure challenge, a public health challenge and a national security challenge.”

Carbon Cuts

For the most part, House representatives were in agreement with the panel that climate change is real and harming not only the environment but the economy and Americans. During the nearly two and half hours of questions that followed the researchers’ testimonies, representatives asked the scientists to identify priorities and sought their suggestions for solutions.

“Human emissions of CO2 must be brought as close to zero as possible with any continued emissions of CO2 balanced by human removal of carbon dioxide from the atmosphere,” said Kopp, who suggested expanding forests and using new, but little-tested technologies as a start. “The faster we reduce emissions, the less severe the effects and the lower the risk of unwelcome surprises,” he added.

Cities, states and a number of companies are already taking action by adopting emission reduction targets, but Kopp says these efforts need to grow dramatically and rapidly to effectively manage climate risk.

But Joseph Majkut, a policy expert with the Niskanen Center, a non-partisan think tank based in Washington, D.C., who also testified, acknowledged, “That’s a challenging thing to do.”

“To even get close, we’ll need significant innovation in low-carbon technology, finance and market design in order to be able to provide reliable, affordable and globally accessible low carbon energy,” Majkut said.

Majkut projected that to reach any temperature target, much less the 1.5 degrees C (2.7 degrees F) of warming goal set by the IPCC, would require carbon capture and storage of fossil fuels as well as carbon removal technologies in conjunction with renewable energy and storage solutions. He then advocated for research into alternatives to reducing global emissions, such as geoengineering technologies that would offset greenhouse gas production.

The scientists’ recommendations align with many facets of the Green New Deal Rep. Alexandria Ocasio-Cortex (D-NY) and Sen. Ed Markey (D-MA) recently proposed. The legislation calls for a massive policy shift that bolsters the U.S. economy and cuts greenhouse gas emissions to zero. Like the solutions Majkut outlined for the House Science Committee, the Green New Deal lists expanding and upgrading renewable energy sources, removing greenhouse gases from the atmosphere and increasing carbon storage as ways to achieve its goal.

Rep. Ralph Norman (R-SC) and others raised concerns about the cost of such an initiative, asking “If the Green New Deal were implemented immediately, wouldn’t it devastate our economy?” But, says Majkut, reducing CO2 associated with economic activity is “one of the cheapest elements” of the bill.

Adaptive Measures

The scientists testifying before the House also recommended prioritizing research into the ways society might adapt to climate change and called on federal support for studies of how climate change will affect communities, a research topic Kristie Ebi, an epidemiologist at the University of Washington in Seattle, is already looking into.

Ebi, another scientist to testify at the hearing, investigates how climate change affects human health. Researchers have discovered Americans are already suffering and dying from climate change and the impacts will likely only get worse.

“Risk from vector-borne diseases such as malaria, Dengue fever and Lyme disease are projected to increase with warming from 1.5 to 2 C (2.7 to 3.6 F) including potential shifts in their geographic range to areas previously unexposed to these diseases,” Ebi said. “Further, our healthcare infrastructure is vulnerable to extreme events with, for example, many hospitals and healthcare clinics located in coastal regions subject to flooding.”

Yet, there are achievable ways to alleviate the projected risks and costs associated with climate change’s impacts on communities, Ebi said, such as “developing early notification response plans for extreme heat … and incorporating climate projections into emergency preparedness and disaster risk management initiatives.”

“These steps can protect health now and provide a basis for effective adaptation to our future climate,” she added.

And if the world does not slow the rise of greenhouse gas emissions, Americans’ health and the U.S. economy will suffer because of impacts associated with mortality and the ability of people to work outdoors, scientists say. More extreme weather events will also affect human health and the economy.

“We know that in 2018, the losses due to extreme weather were roughly $160 billion just to the U.S.,” said Jennifer Francis, an atmospheric scientists at the Woods Hole Research Center in Falmouth, Massachusetts, during her testimony. “But what keeps me up at night is thinking about my own daughter and the world she will face if we do nothing.”



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