. Scientific Frontline

Friday, September 23, 2022

Asteroid that formed Vredefort crater bigger than previously believed

Credits: NASA Earth Observatory Image by Lauren Dauphin / University of Rochester
Illustration by Julia Joshpe

About two billion years ago, an impactor hurtled toward Earth, crashing into the planet in an area near present-day Johannesburg, South Africa. The impactor—most likely an asteroid—formed what is today the biggest crater on our planet. Scientists have widely accepted, based on previous research, that the impact structure, known as the Vredefort crater, was formed by an object about 15 kilometers (approximately 9.3 miles) in diameter that was travelling at a velocity of 15 kilometers per second.

But according to new research from the University of Rochester, the impactor may have been much bigger—and would have had devastating consequences across the planet. This research, published in the Journal of Geophysical Research, provides a more accurate understanding of the large impact and will allow researchers to better simulate impact events on Earth and other planets, both in the past and the future.

“Understanding the largest impact structure that we have on Earth is critical,” says Natalie Allen ’20, now a PhD student at John Hopkins University. Allen is the first author of the paper, based on research she conducted as an undergraduate at Rochester with Miki Nakajima, an assistant professor of Earth and environmental sciences. “Having access to the information provided by a structure like the Vredefort crater is a great opportunity to test our model and our understanding of the geologic evidence so we can better understand impacts on Earth and beyond.”

New research reveals the relationship between particular brain circuits and different aspects of mental wellbeing

Brain circuits and wellbeing
Credit: Miriam Klein-Flugge 

Associate Professor Miriam Klein-Flügge and colleagues looked at brain connectivity and mental health data from nearly 500 people. In particular, they looked at the connectivity of the amygdala – a brain region well known for its importance in emotion and reward processing. The researchers used functional magnetic resonance imaging to consider seven small subdivisions of the amygdala and their associated networks rather than combining the whole region together as previous studies have done.

The team also adopted a more precise approach to the data on mental wellbeing, looking at a large group of healthy people and using questionnaires that captured information about wellbeing in the social, emotional, sleep, and anger domains. This generated more precise data than many investigations which still use broad diagnoses such as depression or anxiety, which involve many different symptoms.

The paper, published in Nature Human Behavior, shows how the improved level of detail about both brain connectivity and wellbeing made it possible to characterize the exact brain networks that relate to these distinct aspects of mental health. The brain connections that mattered most for discerning whether an individual was struggling with sleep problems, for example, looked very different from those that carried information about their social wellbeing.

Robot sleeves for kids with cerebral palsy

Experimental setup for earlier iteration of the proposed robot sleeves.
Credit: Jonathan Realmuto/UCR

UC Riverside engineers are developing low-cost, robotic “clothing” to help children with cerebral palsy gain control over their arm movements.

Cerebral palsy is the most common cause of serious physical disability in childhood, and the devices envisioned for this project are meant to offer long-term daily assistance for those living with it.

However, traditional robots are rigid and not comfortable on the human body. Enabled by a $1.5 million grant from the National Science Foundation, this project is taking the novel approach of building devices from soft textiles, which will also facilitate more natural limb functioning.

“Hard materials don’t interact well with humans,” said Jonathan Realmuto, UCR assistant professor of mechanical engineering and project lead. “What we’re going for by using materials like nylon and elastic are essentially robotic garments.”

These garments will contain sealed, airtight regions that can inflate, making them temporarily rigid, and providing the force for movement.

“Let’s say you want to flex the elbow for a bicep curl. We can inject air into specially designed bladders embedded in the fabric that would propel the arm forward,” Realmuto said.

Mysterious ripples in the Milky Way were caused by a passing dwarf galaxy

Illustration: NASA JPL-Caltech R. Hurt (SSC Caltech)

Using data from the Gaia space telescope, a team led by researchers at Lund University in Sweden has shown that large parts of the Milky Way's outer disk vibrate. The ripples are caused by a dwarf galaxy, now seen in the constellation Sagittarius, that shook our galaxy as it passed by hundreds of millions of years ago.

Our cosmic home, the Milky Way, contains between 100 and 400 billion stars. Astronomers believe that the galaxy was born 13.6 billion years ago, emerging from a rotating cloud of gas composed of hydrogen and helium. Over billions of years, the gas then collected in a rotating disk where the stars, such as our sun, were formed.

In a new study published in Monthly Notices of the Royal Astronomical Society, the research team presents their findings about the stars in the outer regions of the galactic disk.

Thursday, September 22, 2022

Atomic-Scale Imaging Reveals a Facile Route to Crystal Formation

Aluminum hydroxide, depicted here in orange, undergoes fluctuations between structures before forming an ordered crystal. 
Illustration by Nathan Johnson | Pacific Northwest National Laboratory

What do clouds, televisions, pharmaceuticals, and even the dirt under our feet have in common? They all have or use crystals in some way. Crystals are more than just fancy gemstones. Clouds form when water vapor condenses into ice crystals in the atmosphere. Liquid crystal displays are used in a variety of electronics, from televisions to instrument panels. Crystallization is an important step for drug discovery and purification. Crystals also make up rocks and other minerals. Their crucial role in the environment is a focus of materials science and health sciences research.

Scientists have yet to fully understand how crystallization occurs, but the importance of surfaces in promoting the process has long been recognized. Research from Pacific Northwest National Laboratory (PNNL), the University of Washington (UW), and Durham University sheds new light on how crystals form at surfaces. Their results were published in Science Advances.

Previous studies on crystallization led scientists to form the classical nucleation theory—the predominant explanation for why crystals begin to form, or nucleate. When crystals nucleate, they begin as very small ephemeral clusters of just a few atoms. Their small size makes the clusters extremely difficult to detect. Scientists have managed to collect only a few images of such processes.

Heat-resistant nanophotonic material could help turn heat into electricity

His artist’s rendering shows the material reflecting infra-red light while letting other wavelengths pass through.
Image credit: Andrej Lenert

A new nanophotonic material has broken records for high-temperature stability, potentially ushering in more efficient electricity production and opening a variety of new possibilities in the control and conversion of thermal radiation.

Developed by a University of Michigan-led team of chemical and materials science engineers, the material controls the flow of infrared radiation and is stable at temperatures of 2,000 degrees Fahrenheit in air, a nearly twofold improvement over existing approaches.

The material uses a phenomenon called destructive interference to reflect infrared energy while letting shorter wavelengths pass through. This could potentially reduce heat waste in thermophotovoltaic cells, which convert heat into electricity but can’t use infrared energy, by reflecting infrared waves back into the system. The material could also be useful in optical photovoltaics, thermal imaging, environmental barrier coatings, sensing, camouflage from infrared surveillance devices and other applications.

Conventional Computers Can Learn to Solve Tricky Quantum Problems

Hsin-Yuan (Robert) Huang
Credit: Caltech

There has been a lot of buzz about quantum computers and for good reason. The futuristic computers are designed to mimic what happens in nature at microscopic scales, which means they have the power to better understand the quantum realm and speed up the discovery of new materials, including pharmaceuticals, environmentally friendly chemicals, and more. However, experts say viable quantum computers are still a decade away or more. What are researchers to do in the meantime?

A new Caltech-led study in the journal Science describes how machine learning tools, run on classical computers, can be used to make predictions about quantum systems and thus help researchers solve some of the trickiest physics and chemistry problems. While this notion has been proposed before, the new report is the first to mathematically prove that the method works in problems that no traditional algorithms could solve.

"Quantum computers are ideal for many types of physics and materials science problems," says lead author Hsin-Yuan (Robert) Huang, a graduate student working with John Preskill, the Richard P. Feynman Professor of Theoretical Physics and the Allen V. C. Davis and Lenabelle Davis Leadership Chair of the Institute for Quantum Science and Technology (IQIM). "But we aren't quite there yet and have been surprised to learn that classical machine learning methods can be used in the meantime. Ultimately, this paper is about showing what humans can learn about the physical world."

The synthetic rocks help us understand how sought-after rare earth elements form

A selection of some of the rare earth artificial rocks produced by the team. Picture taken at the iCRAG Lab at Trinity College Dublin.
Credit: Trinity College Dublin, The University of Dublin

Researchers from Trinity have shed new light on the formation of increasingly precious rare earth elements (REEs) by creating synthetic rocks and testing their responses to varying environmental conditions. REEs are used in electronic devices and green energy technologies, from smartphones to e-cars.

The findings, just published in the journal Global Challenges, have implications for recycling REEs from electronic waste, designing materials with advanced functional properties, and even for finding new REE deposits hidden around the globe.

Dr Juan Diego Rodriguez-Blanco, Associate Professor in Nanomineralogy at Trinity and an iCRAG (SFI Research Centre in Applied Geosciences) Funded Investigator, was the principal investigator of the work. He said:

“As both the global population and the fight against carbon emissions grow in the wake of global climate change, the demand for REEs simultaneously increases, which is why this research is so important. By growing our understanding of REE formation, we hope to pave the way to a more sustainable future.

“The genesis of rare earth deposits is one of the most complex problems in Earth sciences, but our approach is shedding new light on the mechanisms by which rocks containing rare earths form. This knowledge is critical for the energy transition, as rare earths are key manufacturing ingredients in the renewable energy economy.”

Star Light, Star Bright … But Exactly How Bright?

Astronomers use the brightness of a type of exploding star known as a supernova type IA (seen here as bright blue dot to the left of a remote spiral galaxy) to determine the age and expansion rate of the universe. New calibrations of the luminosity of nearby stars, observed by NIST researchers, could help astronomers refine their measurements.
Credit: NASA, ESA, J. DePasquale (STScI), M. Kornmesser and M. Zamani (ESA/Hubble), A. Riess (STScI/JHU) and the SH0ES team, and the Digitized Sky Survey

A picture may be worth a thousand words, but for astronomers, simply recording images of stars and galaxies isn’t enough. To measure the true size and absolute brightness (luminosity) of heavenly bodies, astronomers need to accurately gauge the distance to these objects. To do so, the researchers rely on “standard candles” -- stars whose luminosities are so well known that they act like light bulbs of known wattage. One way to determine a star’s distance from Earth is to compare how bright the star appears in the sky to its luminosity.

But even standard candles need to be calibrated. For more than a decade, scientists at the National Institute of Standards and Technology (NIST) have been working to improve the methods for calibrating standard stars. They observed two nearby bright stars, Vega and Sirius, in order to calibrate their luminosity over a range of visible-light wavelengths. The researchers are now completing their analysis and plan to release the calibration data to astronomers within the next 12 months.

Not all wildlife recovered in lockdowns, new research finds

European Robin Photo credit: Andy Holmes

When the COVID pandemic started, it was a global crisis for humans – but as humans took shelter, reports of wildlife reclaiming what were once human-dominated spaces abounded. But biologists are noticing the patterns were not repeated around the globe.

Last year, a research team led by University of Manitoba conservation biology professor Nicola Koper found that during the lockdowns most birds in Canada and the USA increased in human-dominated areas, such as cities or near roads. New research, however, shows a different story in other parts of the world.

Koper teamed up with the first author Dr. Miya Warrington and other team members to study responses of birds to lockdowns in the United Kingdom, published today in Proceedings of the Royal Society B. Surprisingly, this research showed that while some British birds increased their use of spaces that they share with humans, many species did not. It seems that some of Brits’ favorite lockdown outdoor activities, like visiting parks and hanging out in our backyards, infringed on birds that share our spaces.

“Although I was happy to see people getting out and enjoying nature, I was also worried that some natural spaces would be flooded with people, and we may accidentally be ‘smothering nature with our love’. We may have created a bit too much human pressure on the very places that bring us joy and comfort,” says lead author Miya Warrington.

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