Sunday, February 06, 2022

Discovery unravels how atomic vibrations emerge in nanomaterials

Advances in microscopy reveal source of phonons’ puzzling behavior

UNIVERSITY OF VIRGINIA SCHOOL OF ENGINEERING AND APPLIED SCIENCE

A hundred years of physics tells us that collective atomic vibrations, called phonons, can behave like particles or waves. When they hit an interface between two materials, they can bounce off like a tennis ball. If the materials are thin and repeating, as in a superlattice, the phonons can jump between successive materials.

Now there is definitive, experimental proof that at the nanoscale, the notion of multiple thin materials with distinct vibrations no longer holds. If the materials are thin, their atoms arrange identically, so that their vibrations are similar and present everywhere. Such structural and vibrational coherency opens new avenues in materials design, which will lead to more energy efficient, low-power devices, novel material solutions to recycle and convert waste heat to electricity, and new ways to manipulate light with heat for advanced computing to power 6G wireless communication.

The discovery emerged from a long-term collaboration of scientists and engineers at seven universities and two U.S. Department of Energy national laboratories. Their paper, Emergent Interface Vibrational Structure of Oxide Superlattices, was published January 26 in Nature.

Eric Hoglund, a postdoctoral researcher at the University of Virginia School of Engineering and Applied Science, took point for the team. He earned his Ph.D. in materials science and engineering from UVA in May 2020 working with James M. Howe, Thomas Goodwin Digges Professor of materials science and engineering. After graduation, Hoglund continued working as a post-doctoral researcher with support from Howe and Patrick Hopkins, Whitney Stone Professor and professor of mechanical and aerospace engineering.

Hoglund’s success illustrates the purpose and potential of UVA’s Multifunctional Materials Integration Initiative, which encourages close collaboration among different researchers from different disciplines to study material performance from atoms to applications.

“The ability to visualize atomic vibrations and link them to functional properties and new device concepts, enabled by collaboration and co-advising in materials science and mechanical engineering, advances MMI’s mission,” Hopkins said.

Hoglund employed microscopy techniques to answer questions raised in experimental results Hopkins published in 2013, reporting on thermal conductivity of superlattices, which Hoglund likens to a Lego building block.

“You can achieve desired material properties by changing how different oxides couple to each other, how many times the oxides are layered and the thickness of each layer,” Hoglund said.

Hopkins expected the phonon to get resistance as it traveled through the lattice network, dissipating thermal energy at each interface of the oxide layers. Instead, thermal conductivity went up when the interfaces were really close together.

“This led us to believe that phonons can form a wave that exists across all subsequent materials, also known as a coherent effect,” Hopkins said. “We came up with an explanation that fit the conductivity measurements, but always felt this work was incomplete.”

“It turns out, when the interfaces become very close, the atomic arrangements unique to the material layer cease to exist,” Hoglund said. “The atom positions at the interfaces, and their vibrations, exist everywhere. This explains why nanoscale-spaced interfaces produce unique properties, different from a linear mixture of the adjoining materials.”

Hoglund collaborated with Jordan Hachtel, an R&D associate in the Center for Nanophase Materials Sciences at Oak Ridge National Laboratory, to connect local atomic structure to vibrations using new generations of electron microscopes at UVA and Oak Ridge. Working with high-spatial-resolution spectroscopic data, they mapped interlayer vibrations across interfaces in a superlattice.

“That’s the major advance of the Nature paper,” Hopkins said. “We can see the position of atoms and their vibrations, this beautiful image of a phonon wave based on a certain pattern or type of atomic structure.”

The Collaborative Trek to Collective Success

The highly collaborative effort began in 2018 when Hoglund was sharing research plans to characterize atomic vibrations at interfaces in perovskite oxides.

“I was going to Oak Ridge to work with Jordan for a week, so Jim and Patrick suggested I take the superlattice samples and just see what we can see,” Hoglund recalled. “The experiments that Jordan and I did at Oak Ridge boosted our confidence in using superlattices to measure vibrations at the atomic or nano-scale.”

During one of his later trips to Tennessee, Hoglund met up with Joseph R. Matson, a Ph.D. student conducting related experiments at Vanderbilt University’s Nanophotonic Materials and Devices laboratory led by Joshua D. Caldwell, the Flowers Family Chancellor Faculty Fellow and associate professor of mechanical engineering and electrical engineering. Using Vanderbilt’s instruments, they conducted Fourier-transform infrared spectroscopy experiments to probe optical vibrations in the entire superlattice. These well-established macroscopic measurements validated Hoglund’s novel microscopy approach.

From these experiments, Hoglund deduced that the properties he cared about — thermal transport and infrared response — stemmed from the interface’s influence on the superlattice’s well-ordered framework of oxygen atoms. The oxygen atoms arrange themselves in an eight-sided structure called an octahedra, with a metal atom suspended inside. The interaction between oxygen and metal atoms causes the octahedra to rotate across the material structure. The oxygen and metal arrangements in this framework generate the unique vibrations and give rise to the material’s thermal and spectral properties.

Back at UVA, Hoglund’s chance conversation with Jon Ihlefeld, associate professor of materials science and engineering and electrical and computer engineering, brought additional members and expertise to the effort. Ihlefeld mentioned that researchers affiliated with Sandia National Laboratories, Thomas Beechem, associate professor of mechanical engineering at Purdue University, and Zachary T. Piontkowski, a senior member of Sandia’s technical staff, were also trying to explain the optical behavior of phonons and had likewise found the exact same oxide superlattices to be an ideal material for their study.

Coincidentally, Hopkins had an ongoing research collaboration with Beechem, albeit with other material systems. “Rather than competing, we agreed to work together and make this something bigger than either of us,” Hoglund said.

Beechem’s involvement had an added benefit, bringing Penn State physicist and materials scientist Roman Engel-Herbert and his student Ryan C. Haisimaier into the partnership to grow material samples for the microscopy experiments underway at UVA, Oak Ridge and Vanderbilt. Up to this point, Ramamoorthy Ramesh, University of California, Berkeley, professor of physics and materials science and engineering, and his Ph.D. students Ajay K. Yadav and Jayakanth Ravichandran were the growers on the team, providing samples to Hopkins’ ExSiTE research group.

“We realized we had all of this really neat experimental data connecting vibrations at atomic and macroscopic length scales, but all of our explanations were still somewhat conjectures that we could not prove absolutely without theory,” Hoglund said.

Hachtel reached out to Vanderbilt colleague Sokrates T. Pantelides, University Distinguished Professor of Physics and Engineering, William A. & Nancy F. McMinn professor of physics, and professor of electrical engineering. Pantelides and his research group members De-Liang Bao and Andrew O’Hara employed density functional theory to simulate atomic vibrations in a virtual material with a superlattice structure.

Their theoretical and computational methods supported exactly the results produced by Hoglund and other experimentalists on the team. The simulation also enabled the experimentalists to understand how every atom in the superlattice vibrates with high precision and how this was related to structure.

At this point, the team had 17 authors: three microscopists, four optical spectroscopists, three computational scientists, five growers and two material scientists. It was time, they thought, to share their findings with the scientific community at large.

An initial peer reviewer of their manuscript advised the team to establish a more direct, causal connection between material structure and material properties. “We measured some cool new phenomena making connections over multiple length scales that should affect material properties, but we had not yet convincingly demonstrated whether and how the known properties changed,” Hoglund said.

Two graduate students in Hopkins’ ExSiTE lab, senior scientist John Tomko and Ph.D. student Sara Makarem, helped provide the final proof. Tomko and Makarem probed the superlattices using infrared lasers and demonstrated that the structure controlled non-linear optical properties and the lifetime of phonons.

“When you send in a photon of one unit of energy, the superlattices double that unit of energy,” Hopkins said. “John and Sara built a new capability in our lab to measure this effect, which we express as the second harmonic generation efficiency of these superlattices.” Their contribution expands the ExSiTE lab capabilities to understand new light-phonon interactions.

“I think this will enable advanced materials discovery,” Hopkins said. “Scientists and engineers working with other classes of materials may now look for similar properties in their own studies. I fully expect we will find that these phonon waves, this coherent effect, exists in a lot of other materials.”

The long-standing collaboration continues. Hoglund is in his second year as a postdoctoral researcher, working with both Howe and Hopkins. Together with Pantelides, Hachtel and Ramesh, he expects they will have new and exciting atomic structure-vibration ideas to share in the near future.

JOURNAL

Nature

DOI

10.1038/s41586-021-04238-z

METHOD OF RESEARCH

Experimental study

SUBJECT OF RESEARCH

Not applicable

ARTICLE TITLE

Emergent interface vibrational structure of oxide superlattices

ARTICLE PUBLICATION DATE

26-Jan-2022

Pythagoras believed that the planets themselves, all heavenly bodies, rang out notes of vibration based on their orbit and distance to each other. We humans simply lack the ability to hear this music of the spheres. These mathematical ratios helped to define every system of intonation throughout history.May 4, 2015

Timeline 002: Pythagoras And The Connection Between ...

The Music of the Spheres - Sensory Studies
https://www.sensorystudies.org › spheres_image

In ancient Greece, Pythagoras and his followers thought that celestial bodies ... had already discovered the workings of musical pitch by way of vibration.

Analysis of Japanese and English folk songs finds cross-cultural regularities in music evolution

A team of researchers from Japan, the U.K. and New Zealand has found that despite language differences, Japanese and English folk songs have similar cross-cultural regularities in their musical evolution. In their paper published in the journal Current Biology, the group describes modeling melodies as sequences built from an "alphabet" of 12 scale degrees and analyzing their evolution.

Analysis of Japanese and English folk songs highlights cross-cultural regularities in music evolution — Substitution distance and rhythmic function predict rates of musical evolution Left-hand side

As the researchers note, folk songs are difficult to define, but most listeners can recognize them when they hear them. And, as they also note, folk songs typically represent the times in which they were written and very often evolve over time as conditions change. In this new effort, they sought to learn more about the evolutionary processes of folk songs—both those written in Japanese and those written in English (British and American)—and if there were similarities between the two types. To conduct an analysis of such songs, they first defined folk songs as those that have been transmitted orally from one generation to the next. They next converted the musical notation for more than 10,000 songs into letter sequences so that they could be read and processed by a computer algorithm. The algorithm they used was developed for analyzing evolutionary changes in nature but the researchers thought it could provide insights into folk song evolution as well.

In studying the results provided by the algorithm, the researchers found they were able to track insertions and deletions to songs over time—where the number of notes in a song remained constant but the notes had different values in different places. They also found that insertions or deletions were more common than substitutions. They also noted that the impact on the songs from such insertions and deletions was more profound in the Japanese songs. The researchers also found that changes to notes that played a major role in the folk songs over time were less likely to occur than those that played a more minor role, regardless of language.

The researchers conclude by suggesting that evolutionary changes to folk songs occurred in much the same way in both languages, despite them being written and sung in different scales and tones.Babies are sensitive to rhyme, rhythm and phrases in children's songs

More information: Patrick E. Savage et al, Sequence alignment of folk song melodies reveals cross-cultural regularities of musical evolution, Current Biology (2022). DOI: 10.1016/j.cub.2022.01.039]

Journal information: Current Biology ]

DR DOOLITTLE I PRESUME

Fish Have 'Talked' For 155 Million Years, And Now You Can Hear Their 'Voices'

Catfish in a pond. (Sutthiwat Srikhrueadam/Moment/Getty Images)
NATURE

TESSA KOUMOUNDOUROS
5 FEBRUARY 2022

All manner of croaks, chirps, and deep trombone moans permeate Earth's waters, just like the cacophony of sounds that fill its forest air. For example, reefs are surprisingly noisy places, and many of the noisemakers are fish.

"We've known for a long time that some fish make sounds, but fish sounds were always perceived as rare oddities,'' said Cornell University ecologist Aaron Rice.

It was likely assumed fish relied primarily on other means of communication, from color signals and body language to electricity. But recent discoveries have demonstrated fish even have dawn and dusk choruses, just like birds.

"They've probably been overlooked because fishes are not easily heard or seen, and the science of underwater acoustic communication has primarily focused on whales and dolphins," said Cornell evolutionary neuroscientist Andrew Bass.

"But fishes have voices too."

And some sound like the most magnificent foghorn:

Scouring records of anatomical descriptions, sound recordings, and vocal accounts, Rice and colleagues identified several physiological features that allow the ray-finned (Actinopterygii) group of fishes to make these noises without vocal cords. This group contains more than 34,000 currently living species.

"They can grind their teeth or make movement noise in the water, and we do see a number of specializations that are involved," Rice told Syfy Wire.

"Probably the most common adaptation are muscles associated with swim bladders. In fact, the swim bladder muscles of the toadfish are the fastest contracting vertebrate skeletal muscles. These are high-performing adaptations."

Of 175 families of fishes, two-thirds were likely to communicate with sound – much more talkative fish than the one-fifth previously estimated. Analysis suggests these vocal communications may have evolved independently at least 33 times in fishes.

Clearly, fish have some important things to say.

What's more, fish-speak appeared around 155 million years ago, which interestingly happens to be around the same time evidence suggests land animals with backbones first vocalized too – animals we eventually evolved from.

"Our results strongly support the hypothesis that soniferous behavior is ancient," the team wrote in their paper. "Together, these findings highlight the strong selection pressure favoring the evolution of this character across vertebrate lineages."

Some fish groups were chattier than others, with toadfish and catfish amongst the most verbose groups. However, Rice and the team caution that their analysis only shows the presence of vocalizing fish rather than the presence of absence – it may just be that we just haven't listened hard enough to hear the other groups out yet.

As for what they're trying to say, fish are probably jabbering about food, warnings of danger, social happenings (including territorial arguments), and of course, sex. But who knows what other fishy secrets they may recite!

Some researchers have even been trying to use fish songs as underwater siren calls to beckon fish back to rejuvenating coral reefs.

"Fish do everything. They breathe air, they fly, they eat anything and everything – at this point, nothing would surprise me about fishes and the sounds that they can make," said Rice.

This research was published in Ichthyology & Herpetology.

SPLATTER ART

The heart of the Milky Way looks like contemporary art in this new radio image

Wispy filaments accent the brightest spot, supermassive black hole Sagittarius A*

The MeerKAT telescope array in South Africa provided this image of radio emissions from the center of the Milky Way. Stronger radio signals are shown in red and orange false color. Fainter zones are colored in gray scale, with darker shades indicating stronger emissions.
I. HEYWOOD/SARAO

By Lisa Grossman
FEBRUARY 3, 2022 AT

An image that looks like a trippy Eye of Sauron or splatter of modern art is actually a new detailed look at the Milky Way’s chaotic center, as seen in radio wavelengths.

The image was taken with the MeerKAT radio telescope array in South Africa over the course of three years and 200 hours of observing. It combines 20 separate images into a single mosaic, with the bright, star-dense galactic plane running horizontally. The MeerKAT team describes the image in a paper to be published in the Astrophysical Journal.

MeerKAT captured radio waves from several astronomical treasures, including supernovas, stellar nurseries and the energetic region around the supermassive black hole at the galaxy’s center (SN: 8/31/21; SN: 9/17/19). One puffy supernova remnant can be seen in the bottom right of the image, and the supermassive black hole shows up as the bright orange “eye” in the center

The supermassive black hole Sagittarius A*, which sits at the center of the Milky Way, shines in the lower center of this closeup image from the MeerKAT radio telescope. Mysterious thin filaments accent the galaxy’s center.

I. HEYWOOD/SARAO

Other intriguing features are the many wispy-looking radio filaments that slice mostly vertically through the image. These filaments, a handful of which were first spotted in the 1980s, are created by accelerated electrons gyrating in a magnetic field and creating a radio glow. But the filaments are hard to explain because there’s no obvious engine to accelerate the particles.

“They were a puzzle. They’re still a puzzle,” says astrophysicist Farhad Yusef-Zadeh of Northwestern University in Evanston, Ill., who discovered the filaments serendipitously as a graduate student.

Previously, scientists knew of so few filaments that they could study the features only one at a time. Now MeerKAT has revealed hundreds of them, Yusef-Zadeh says. Studying the strands all together could help reveal their secrets, he and colleagues report in a paper to be published in the Astrophysical Journal Letters. “We’re definitely one step closer to seeing what these guys are about,” he says.

The observatory released the data behind the imagery as well, so other scientists can run their own analyses on it. “There’s going to be a lot of science coming,” Yusef-Zadeh says.

Questions or comments on this article? E-mail us at feedback@sciencenews.org

CITATIONS

I. Heywood et al. The 1.28 GHz MeerKAT galactic center mosaic. arXiv:2201.10541. Submitted January 25, 2022.

F. Yusef-Zadeh et al. Statistical properties of the population of the galactic center filaments: The spectral index and equipartition magnetic field. arXiv:2201.10552v1. Submitted January 25, 2022.

About Lisa Grossman is the astronomy writer. She has a degree in astronomy from Cornell University and a graduate certificate in science writing from University of California, Santa Cruz. She lives near Boston.

Too Many Disk Galaxies Than Theory Allows

Prof. Dr. Pavel Kroupa (left) and Moritz Haslbauer (right) with a projection of the Andromeda galaxy. CREDIT Photo: Volker Lannert/University of Bonn

February 6, 2022

By Eurasia Review

The Standard Model of Cosmology describes how the universe came into being according to the view of most physicists. Researchers at the University of Bonn have now studied the evolution of galaxies within this model, finding considerable discrepancies with actual observations. The University of St. Andrews in Scotland and Charles University in the Czech Republic were also involved in the study. The results have now been published in the Astrophysical Journal.

Most galaxies visible from Earth resemble a flat disk with a thickened center. They are therefore similar to the sports equipment of a discus thrower. According to the Standard Model of Cosmology, however, such disks should form rather rarely. This is because in the model, every galaxy is surrounded by a halo of dark matter. This halo is invisible, but exerts a strong gravitational pull on nearby galaxies due to its mass. “That’s why we keep seeing galaxies merging with each other in the model universe,” explains Prof. Dr. Pavel Kroupa of the Helmholtz Institute for Radiation and Nuclear Physics at the University of Bonn.

This crash has two effects, the physicist explains: “First, the galaxies penetrate in the process, destroying the disk shape. Second, it reduces the angular momentum of the new galaxy created by the merger.” Put simply, this greatly decreases its rotational speed. The rotating motion normally ensures that the centrifugal forces acting during this process cause a new disk to form. However, if the angular momentum is too small, a new disk will not form at all.

Large discrepancy between prediction and reality

In the current study, Kroupa’s doctoral student, Moritz Haslbauer, led an international research group to investigate the evolution of the universe using the latest supercomputer simulations. The calculations are based on the Standard Model of Cosmology; they show which galaxies should have formed by today if this theory were correct. The researchers then compared their results with what is currently probably the most accurate observational data of the real Universe visible from Earth.

“Here we encountered a significant discrepancy between prediction and reality,” Haslbauer says: “There are apparently significantly more flat disk galaxies than can be explained by theory.” However, the resolution of the simulations is limited even on today’s supercomputers. It may therefore be that the number of disk galaxies that would form in the Standard Model of Cosmology has been underestimated. “However, even if we take this effect into account, there remains a serious difference between theory and observation that cannot be remedied”, Haslbauer points out.

The situation is different for an alternative to the Standard Model, which dispenses with dark matter. According to the so-called MOND theory (the acronym stands for “MilgrOmiaN Dynamics), galaxies do not grow by merging with each other. Instead, they are formed from rotating gas clouds that become more and more condensed. In a MOND universe, galaxies also grow by absorbing gas from their surroundings. However, mergers of full-grown galaxies are rare in MOND. “Our research group in Bonn and Prague has uniquely developed the methods to do calculations in this alternative theory,” says Kroupa, who is also a member of the Transdisciplinary Research Units “Modelling” and “Matter” at the University of Bonn. “MOND’s predictions are consistent with what we actually see.”

Challenge for the Standard Model

However, the exact mechanisms of galaxy growth are not yet fully understood, even with MOND. Additionally, in MOND, Newton’s laws of gravity do not apply under certain circumstances, but need to be replaced by the correct ones. This would have far-reaching consequences for other areas of physics. “Nevertheless, the MOND theory solves all known extragalactic cosmological problems despite being originally formulated to address galaxies only,” says Dr. Indranil Banik, who was involved in this research. “Our study proves that young physicists today still have the opportunity to make significant contributions to fundamental physics,” Kroupa adds.

New insight into blobs improves understanding of a universal process

by Raphael Rosen, Princeton University

Researchers at the U.S. Department of Energy's (DOE) Princeton Plasma Physics Laboratory (PPPL) have gained insight into a fundamental process found throughout the universe. They discovered that the magnetic fields threading through plasma, the charged state of matter composed of free electrons and atomic nuclei, can affect the coming together and violent snapping apart of the plasma's magnetic field lines. This insight could help scientists predict the occurrence of coronal mass ejections, enormous burps of plasma from the sun that could threaten satellites and electrical grids on Earth.

The scientists focused on the role of guide fields, magnetic fields threading through plasma blobs, or chunks, known as plasmoids. The guide fields add rigidity to the system and ultimately affect the ratio of large plasmoids to small ones and help determine how much reconnection occurs.

Plasmoid reconnection resembles the parallel computing that occurs in smart phones or in high-powered computers that model the weather. During this computing, many processors are calculating simultaneously and making the overall calculation rate quicker. Similarly, plasmoids speed up the overall rate of reconnection by making it occur in many places at once.

"Understanding how guide magnetic fields affect plasmoids could give us a better idea of what affects magnetic reconnection on the sun and stars, and throughout the cosmos," said Stephen Majeski, lead author of a paper reporting the results in Physics of Plasmas and a graduate student in Princeton University's Program in Plasma Physics. "Guide fields are a knob we can turn up to reveal new information."

The results provide insight into the ejection of large masses of plasma that speed across space and strike the Earth's magnetosphere, the sheath of magnetic field lines surrounding our planet that protects us from high-energy particles. These giant plasma burps, if large enough, could damage the satellites that enable smart phones to provide driving directions and other applications. The burps could also damage electrical power grids on Earth. "This is all something you definitely want to be aware of," Majeski said.

"This is new territory for plasmoid reconnection research," said Hantao Ji, professor of astrophysical science at Princeton University and distinguished research fellow at PPPL, who helps manage PPPL's Magnetic Reconnection Experiment (MRX) that studies reconnection. "Majeski has added to our knowledge about guide fields to make progress toward understanding large-scale reconnection based on plasmoids. Nobody has looked at guide fields in this way before."

Plasmoid reconnection with guide fields also occurs in doughnut-shaped tokamaks, the most widely used type of fusion facility around the world that use powerful magnets to confine plasma in the effort to harness on Earth fusion, the power that drives the sun and stars. Fusion combines light elements in the form of plasma to generate massive amounts of energy, a process that scientists are seeking to replicate for a virtually inexhaustible supply of power to generate electricity.

The researchers plan to make the models more accurate by including more physical effects, like the speed at which plasmoids combine. They also intend to perform experiments using MRX and PPPL's new Facility for Laboratory Reconnection Experiment (FLARE), the large successor to MRX. FLARE will help probe how quickly reconnection takes place in large laboratory plasmas that are more relevant to astrophysical plasmas, and how the magnetic energy turns into explosive thermal energy.Research reveals how plasma swirling around black holes can produce heat and light

More information: Stephen Majeski et al, Guide field effects on the distribution of plasmoids in multiple scale reconnection, Physics of Plasmas (2021). DOI: 10.1063/5.0059017

Journal information: Physics of Plasmas

Provided by Princeton University

Astronomers set up anti-satellite initiative

Sky watchers don’t want satellite constellations getting in the way of astronomy observations or “humanity’s enjoyment of the night sky”

Astronomers from across the world have launched an initiative to curb the impact of artificial satellites on important astronomical research, arguing for tighter regulations on projects like Elon Musk’s Starlink network.

The International Astronomical Union (IAU) announced the creation of the Centre for the Protection of the Dark and Quiet Sky on Thursday, with president Debra Elmegreen saying it would help ensure that technological advances “do not inadvertently impede our study and enjoyment of the sky.”

The center describes its main mission as being to “mitigate the negative impact of satellite constellations on ground-based optical and radio astronomy observations as well as humanity’s enjoyment of the night sky.”

The body will engage with policymakers around the world in an attempt to tighten regulations on man-made satellites and space infrastructure. It will also push companies like Elon Musk's Starlink and Amazon’s Project Kuiper to minimize light pollution created with their satellites.

The work will be led by the US National Optical-Infrared Astronomy Research Laboratory (NOIRLab) in Tucson, Arizona, which is a center for optical astronomy, and the Square Kilometre Array Organisation (SKAO), which is headquartered in Manchester, UK and is delivering the world’s most powerful networks of radio telescopes.

Satellite networks delivering broadband internet are of the biggest concern for the scientists, as thousands of objects orbit the Earth at a relatively low altitude of only a few hundred kilometers. Their quick movement during dusk and dawn leaves bright lines that can be traced by telescopes and interfere with the readings. The satellite transmissions can also meddle with radio telescopes and astronomy antennas.

Astronomers Join Forces to Prevent

Starlink, Satellite Swarms From Polluting

Skies

The International Astronomical Union creates a new

coordination center devoted to the protection of night

skies from satellite mega-constellations, including

SpaceX's Starlink.

By Michael Kan
February 4, 2022

Satellite streaks from SpaceX's Starlink network.

(Photo: Mike Lewinsky via IAU)

The astronomical community is setting up a center to work with companies and governments on preventing satellite networks, including SpaceX’s Starlink, from polluting the night sky.

The effort comes from the International Astronomical Union, which is made up of 12,000 members across the globe. On Thursday, the union announced a new “IAU Centre for the Protection of the Dark and Quiet Sky from Satellite Constellation Interference.”

The center was created out of concern that next-generation satellite networks will one day interfere with astronomical observations. SpaceX’s Starlink, for example, is designed to deliver high-speed broadband to millions of users across the planet. But to do so, the company needs to launch tens of thousands of satellites into orbit, which risk causing streaks across the night sky. Other companies, including Amazon, have proposed large constellations too.

The streaks won't just photo-bomb astronomy images; they could also disrupt scientific observations, including of near-Earth asteroids, the IAU said in a press briefing on Thursday.

“Astronomy is facing a watershed moment of increasing interference with observations and loss of science,” said Connie Walker, a scientist at the NOIRLab, an astronomy research lab. “At the moment there is little to no regulation in space with respect to optical astronomy,” she added.

However, the IAU's new center isn’t necessarily trying to stop the satellites from launching. Instead, the effort is about “mitigating” the negative effects from the upcoming constellations as companies develop them. The IAU also emphasized the center is focused on taking a “cooperative approach” with the satellite industry.

According to Walker, the IAU has already established relationships with three satellite internet companies including SpaceX, Amazon’s Project Kuiper, and OneWeb, and is talking with others. “A guidelines agreement with industry is in process at this moment,” she added. “We have confidence we can agree on some mitigation solutions, specifically before the design of the satellites has actually started.”

In addition, the center plans on coming up with best practices companies can implement when building their satellites to prevent them from reflecting too much light in the night sky. (SpaceX itself has already been designing new satellites to limit their brightness.)

At the same time, IAU plans to lobby lawmakers and policy makers—such as the FCC, Congressional committees, and the United Nations—on the need for better regulations.

“The goal of these kinds of policy activities is to make sure that good intentions of industry can also be codified into achieving regulations for all space actors,” said Richard Green, an astronomer at the University of Arizona. “If the profit motive (from companies) does start to intrude and make these mitigations difficult for them, we have some backup to say it really is a requirement that they look into these issues."

A Tracking System is now Scanning the Entire sky Every 24 Hours Looking for Dangerous Asteroids

FEBRUARY 4, 2022 BY ANDY TOMASWICK
As evidenced by a recent Netflix movie, dangerous asteroids can come from anywhere. So there was an obvious weakness in our asteroid defense system when only one of the hemispheres was covered by telescopes that constantly scan the sky. That was the case until recently, with the expansion of the Asteroid Terrestrial-impact Last Alert System (ATLAS) system into the southern hemisphere.
ATLAS, funded by NASA and run by the University of Hawai’i, was originally just two telescopes set up on Haleakal? and Maunaloa, two separate parts of Hawai’i. After becoming fully operational in 2017, the system was able to scan the sky every 24 hours, barring any cloud cover, to watch for any potential moving asteroids. But from their vantage point, they could only scan half of the sky.
One of the telescopes being lifted into place in South Africa.
Credit – Willie Koorts (SAAO)
NASA funded two more telescopes in the southern hemisphere to rectify that problem – one located in South Africa and one in Chile. The one in South Africa was contracted to the South African Astronomical Observatory, while the Chilean telescope was supported by a public-private consortium that included the Millennium Institute for Astrophysics and Obstech, a company that runs a private observatory.
The Covid pandemic slowed down the installation process and bungled up some supply chains, but recently both telescopes achieved first light. Importantly, they did so at different times of the day, allowing observes located in Hawai’i to remotely monitor the dark sky over South Africa and Chile during the daytime on their island.
ATLAS telescope located on Maui
Credit – Henry Weiland
Those observations have already been a success, with the South African observatory identifying its first Near-Earth Object on January 22nd. 2022 BK, as it is now known, is a 100-m asteroid that poses no threat to Earth. However, asteroids of a similar size could potentially wipe out an entire region if they impact the planet. ATLAS would be capable of providing about three weeks warning of any asteroid large enough to cause such devastation. Even for smaller asteroids, such as a 20-m asteroid that could wipe out a city, it was capable of providing at least 24 hours’ notice.
While that might not seem like a lot of time, it is the best system so far for providing such detections. However, it does work with other systems, such as Pan-STARRS and the Catalina Sky Survey, to fully understand what hazardous asteroids may be in the area. Humanity could use all the help it could get in that regard.
Learn More:
University of Hawai’i at Manoa – Expanded UH asteroid tracking system can monitor entire sky
NASA – NASA Asteroid Tracking System Now Capable of Full Sky Search
Republicworld.com – NASA’s Enhanced ATLAS Observatory To Scan Entire Sky For 24 Hrs To Track Killer Asteroids
ATLAS – Asteroid Terrestrial-impact Last Alert System
NASA State-of-the-Art Asteroid Tracking System Now Capable of Full Sky Search

By NASA FEBRUARY 3, 2022
The NASA-funded Asteroid Terrestrial-impact Last Alert System (ATLAS)—a state-of-the-art asteroid detection system operated by the University of Hawai‘i (UH) Institute for Astronomy (IfA) for the agency’s Planetary Defense Coordination Office (PDCO)—has reached a new milestone by becoming the first survey capable of searching the entire dark sky every 24 hours for near-Earth objects (NEOs) that could pose a future impact hazard to Earth. Now comprised of four telescopes, ATLAS has expanded its reach to the southern hemisphere from the two existing northern-hemisphere telescopes on Haleakala and Maunaloa in Hawai‘i to include two additional observatories in South Africa and Chile.
From left to right: Sutherland ATLAS station during construction in South Africa. Credit: Willie Koorts (SAAO); Chilean engineers and astronomers installing the ATLAS telescope at El Sauce Observatory. Credit: University of Hawaii; Illustration of NASA’s DART spacecraft and the Italian Space Agency’s (ASI) LICIACube prior to impact at the Didymos binary system. Credit: NASA/Johns Hopkins, APL/Steve Gribben; Illustration of the NEO Surveyor spacecraft
“An important part of planetary defense is finding asteroids before they find us, so if necessary, we can get them before they get us” said Kelly Fast, Near-Earth Object Observations Program Manager for NASA’s Planetary Defense Coordination Office. “With the addition of these two telescopes, ATLAS is now capable of searching the entire dark sky every 24 hours, making it an important asset for NASA’s continuous effort to find, track, and monitor NEOs.”
UH IfA developed the first two ATLAS telescopes in Hawai‘i under a 2013 grant from NASA’s Near-Earth Objects Observations Program, now part of NASA’s PDCO, and the two facilities on Haleakala and Maunaloa, respectively, became fully operational in 2017. After several years of successful operation in Hawai‘i, IfA competed for additional NASA funds to build two more telescopes in the southern hemisphere. IfA sought partners to host these telescopes, and selected the South African Astronomical Observatory (SAAO) in South Africa and a multi-institutional collaboration in Chile. The ATLAS presence augments already substantial astronomical capability in both countries.
Each of the four ATLAS telescopes can image a swath of sky 100 times larger than the full moon in a single exposure. The completion of the two final telescopes, which are located at Sutherland Observing Station in South Africa and El Sauce Observatory in Chile, enable ATLAS to observe the night sky when it is daytime in Hawai‘i.
To date, the ATLAS system has discovered more than 700 near-Earth asteroids and 66 comets, along with detection of 2019 MO and 2018 LA, two very small asteroids that actually impacted Earth. The system is specially designed to detect objects that approach very close to Earth – closer than the distance to the Moon, about 240,000 miles or 384,000 kilometers away. On January 22, ATLAS-Sutherland in South Africa discovered its first NEO, 2022 BK, a 100-meter asteroid that poses no threat to Earth.
The addition of the new observatories to the ATLAS system comes at a time when the agency’s Planetary Defense efforts are on the rise. NASA’s Double Asteroid Redirection Test (DART)—the world’s first full-scale mission to test a technology for defending Earth against potential asteroid impacts—launched November 24, 2021 on a SpaceX Falcon 9 rocket from Space Launch Complex 4 East at Vandenberg Space Force Base in California. DART will deflect a known asteroid, which is not a threat to Earth, to slightly change the asteroid’s motion in a way that can be accurately measured using ground-based telescopes.
Additionally, work on the agency’s Near-Earth Object Surveyor space telescope (NEO Surveyor) is underway after receiving authorization to move forward into Preliminary Design, known as Key Decision Point- B. Once complete, the infrared space telescope will expedite the agency’s ability to discover and characterize most of the potentially hazardous NEOs, including those that may approach Earth from the daytime sky.
“We have not yet found any significant asteroid impact threat to Earth, but we continue to search for that sizable population we know is still to be found. Our goal is to find any possible impact years to decades in advance so it can be deflected with a capability using technology we already have, like DART,” said Lindley Johnson, planetary defense officer at NASA Headquarters. “DART, NEO Surveyor, and ATLAS are all important components of NASA’s work to prepare Earth should we ever be faced with an asteroid impact threat.”
The University of Hawai‘i ATLAS is funded through a grant from the Near-Earth Object Observations Program administered by NASA’s PDCO. The Johns Hopkins Applied Physics Lab manages the DART mission for NASA’s PDCO as a project of the agency’s Planetary Missions Program Office (PMPO). NEO Surveyor is being developed by NASA’s Jet Propulsion Laboratory in Southern California and the University of Arizona and managed by NASA’s PMPO with program oversight by the PDCO. NASA established the PDCO in 2016 to manage the agency‘s ongoing efforts in Planetary Defense.

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