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An image from the James Webb Space Telescope.

Webb Space Telescope reveals birth of galaxies, how universe became transparent

UCLA astrophysicists shed light on how hydrogen fog burned away after the Big Bang

An image from the James Webb Space Telescope

An image from the James Webb Space Telescope. A pair of UCLA-led studies demonstrate some of the scientific advances that the telescope is making possible. | NASA


Holly Ober | November 17, 2022

Key takeaways:
• UCLA astrophysicists are among the first scientists to use the James Webb Space Telescope to get a glimpse of the earliest galaxies in the universe.
• The studies reveal unprecedented detail about events that took place within the first billion years after the Big Bang.
• The UCLA projects were among a small number selected by NASA to test the capabilities of the Webb telescope.

The earliest galaxies were cosmic fireballs converting gas into stars at breathtaking speeds across their full extent, reports a UCLA-led study published in a special issue of the Astrophysical Journal.

The research, based on data from the James Webb Space Telescope, is the first study of the shape and structure of those galaxies. It shows that they were nothing like present-day galaxies in which star formation is confined to small regions, such as the constellation of Orion in our own Milky Way galaxy.

“We’re seeing galaxies form new stars at an electrifying pace,” said Tommaso Treu, the study’s lead author, a UCLA professor of physics and astronomy. “Webb’s incredible resolution allows us to study these galaxies in unprecedented detail, and we see all of this star formation occurring within the regions of these galaxies.”

Treu directs the GLASS–JWST Early Release Science Program, whose first results are the subject of the special journal issue. Another UCLA-led study in the issue found that galaxies that formed soon enough after the Big Bang — within less than a billion years — might have begun burning off leftover photon-absorbing hydrogen, bringing light to a dark universe.

“Even our very best telescopes really struggled to confirm the distances to such far away galaxies, so we didn’t know whether they rendered the universe transparent or not,” said Guido Roberts-Borsani, a UCLA postdoctoral researcher who led the study. “Webb is showing us that not only can it do the job, but it can do it with astonishing ease. It’s a game changer.”

Those findings are two of many breathtaking discoveries by UCLA astrophysicists who are among the first to peer through a window to the past newly opened by Webb.

Webb is the largest near-infrared telescope in space, and its remarkable resolution offers an unparalleled view of objects so distant that their light takes billions of years to reach Earth. Although those objects have aged by now, light from only their earliest moments has had enough time to travel through the universe to end up on Webb’s detectors. As a result, not only has the Webb functioned as a sort of time machine — taking scientists back to the period shortly after the Big Bang — but the images it’s producing have become a family album, with snapshots of infant galaxies and stars.

GLASS–JWST was one of 13 Early Release Science projects selected by NASA in 2017 to quickly produce publicly accessible datasets and to demonstrate and test the capabilities of instruments on the Webb.

The project seeks to understand how and when light from the first galaxies burned through the hydrogen fog left over from the Big Bang — a phenomenon and time period called the Epoch of Reionization — and how gas and heavy elements are distributed within and around galaxies over cosmic time. Treu and Roberts-Borsani use three of the Webb’s innovative near-infrared instruments to take detailed measurements of distant galaxies in the early universe.

The Epoch of Reionization is a period that remains poorly understood by scientists. Until now, researchers have not had the extremely sensitive infrared instruments needed to observe galaxies that existed then. Prior to cosmic reionization, the early universe remained devoid of light because ultraviolet photons from early stars were absorbed by the hydrogen atoms that saturated space.

Scientists think that sometime within the universe’s first billion years radiation emitted by the first galaxies and possibly by the first black holes caused the hydrogen atoms to lose electrons, or ionize, preventing photons from “sticking” to them and clearing a pathway for the photons to travel across space. As galaxies began to ionize larger and larger bubbles, the universe became transparent and light traveled freely, as it does today, allowing us to view a brilliant canopy of stars and galaxies each night.

Roberts-Borsani’s finding that galaxies formed faster and earlier than previously thought could confirm that they were the culprits of cosmic reionization. The study also confirms the distances to two of the farthest galaxies known using a new technique that allows astronomers to probe the beginning of cosmic reionization.


This article originally appeared in the UCLA Newsroom. For more news and updates from the UCLA College, visit college.ucla.edu/news.

Dysmus+Kisilu+with+Tony+Pritzker+in+background

Dysmus Kisilu wins UCLA’s Pritzker Award for environmental innovators

Kenyan entrepreneur and his company, Solar Freeze, receive $100,000 prize for reducing food waste

Dysmus Kisilu speaking with Tony Pritzker in background

Dysmus Kisilu was honored for finding an environmentally friendly way to help small Kenyan farms preserve their produce in order to sell it during periods of peak demand. Tony Pritzker looked on while Kisilu spoke at the Nov. 10 award ceremony. | Damon Cirulli


David Colgan | November 11, 2022

Kenyan entrepreneur Dysmus Kisilu and his business, Solar Freeze, received the 2022 Pritzker Emerging Environmental Genius Award from the UCLA Institute of the Environment and Sustainability.

Kisilu’s company rents solar-powered coolers to reduce waste, curb carbon emissions and improve the marketability of crops on small, rural farms in Kenya. He was honored during a ceremony at the UCLA Meyer and Renee Luskin Conference Center on Nov. 10.

“To the smallholder farmers that I work with, this is for you,” Kisilu said.

The Pritzker Award, which is presented annually, carries a prize of $100,000 that is funded through a portion of a $20 million gift to UCLA from the Anthony and Jeanne Pritzker Family Foundation. It is the field’s first major honor specifically for innovators under the age of 40 — those whose work stands to benefit most from the prize money and the prestige it conveys.

Kisilu co-founded Solar Freeze in 2018, bringing solar-powered cold storage to small Kenyan farms — enabling them to reduce food waste without increasing carbon emissions. The storage units, which are made using old shipping containers, allow farmers to preserve perishable produce inexpensively, giving them leverage to sell harvests after times of peak production when they command higher prices, which can help maximize their profits.

The company aims to further its mission with a new mobile app and by expanding to other parts of Africa.

Kisilu was nominated by Jaime Carlson, a senior advisor in strategy and investment at Softbank Energy, a business that promotes the spread of renewable energy. Carlson said she was struck by how Kisilu “thinks deeply and thoughtfully” to create solutions that fit local communities and market conditions.

The Pritzker Award was launched in 2017, and for the first time since 2019, the presentation was held in person — the 2020 and 2021 events were streamed online due to the pandemic. The 2022 award celebration was kicked off earlier in the day by a series of discussions among UCLA experts and international environmental leaders.

Marilyn Raphael, director of UCLA Institute of the Environment and Sustainability, saluted Kisilu, the other nominees, and the other innovators and scholars who attended the award ceremony.

“You have already touched many lives, and what you do every day will touch lives and inspire environmental heroes for generations to come,” she said.

The other two finalists for the award were Resson Kantai Duff, a conservationist who fosters understanding and stewardship of nature in communities that live among lions; and Tiana Williams-Clausen, director of the Wildlife Department of the Yurok Tribe, who is helping to restore wildlife to Yurok lands around the Klamath River.

From left, Dysmus Kisilu with Marilyn Raphael of the UCLA Institute of the Environment and Sustainability, Pritzker Award finalist Tiana Williams-Clausen and Tony Pritzker at the 2022 Pritzker Emerging Environmental Genius Award ceremony.

From left, Dysmus Kisilu with Marilyn Raphael of the UCLA Institute of the Environment and Sustainability, Pritzker Award finalist Tiana Williams-Clausen and Tony Pritzker at the 2022 Pritzker Emerging Environmental Genius Award ceremony. | Damon Cirulli


The distinguished panel of judges who chose Kisilu as this year’s winner was made up of Kara Hurst, head of worldwide sustainability at Amazon; Chanell Fletcher, deputy executive officer of environmental justice at the California Air Resources Board; Lori Garver, CEO of the Earthrise Media; and Ida Levine, lead expert on policy and regulation for the board of Impact Investing Institute.

Kisilu’s honor was presented by Tony Pritzker, who founded the award and is a member of the Institute of the Environment and Sustainability’s advisory board.

“The objective of all this is to honor you at such a great point in your lives — giving you the opportunity to take it to the next level,” Pritzker said.


This article originally appeared in the UCLA Newsroom. For more news and updates from the UCLA College, visit college.ucla.edu/news.

Miguel García-Garibay in the Royce Hall portico

Miguel García-Garibay appointed senior dean of UCLA College

The longtime faculty member will continue to lead the division of physical sciences

Miguel García-Garibay

UCLA Newsroom | November 1, 2022

Miguel García-Garibay, dean of physical sciences, has been appointed senior dean of the UCLA College, UCLA Executive Vice Chancellor and Provost Darnell Hunt announced. García-Garibay’s two-year term begins today, as current senior dean David Schaberg steps down.

The five deans of the UCLA College lead their respective divisions — physical sciences, life sciences, social sciences, humanities and undergraduate education — and share responsibility for college-wide issues and functions. García-Garibay will continue in his role as physical sciences dean, and as senior dean will be responsible for coordinating planning, budgeting, activities and decisions related to staffing, policies and development across the college. He will also represent the college at meetings and events on campus, systemwide and externally.

García-Garibay joined the UCLA chemistry and biochemistry faculty in 1992 and became dean of physical sciences in 2016. As dean, he has provided thoughtful and strategic leadership and developed a culture of cooperation and inclusion. Over the past six years, he has expanded the division’s academic offerings, led multiple collaborations in research and inclusive teaching, invested in the student experience, and had great success in recruiting and retaining exceptional faculty.

“Chancellor Block and I look forward to working with Dean García-Garibay in this additional role for the benefit of the college and UCLA as a whole,” Hunt said.


This article originally appeared in the UCLA Newsroom. For more news and updates from the UCLA College, visit college.ucla.edu/news.

Person wiping sweat off brow

Are extreme heat waves happening more than expected? UCLA research says not yet.

The temperatures that baked the Pacific Northwest in 2021 should happen roughly once in 10,000 years

Person wiping sweat off brow

“The 2021 Pacific Northwest heat wave appears to be the result of climate change and extraordinarily bad luck with natural variability,” says UCLA’s Karen McKinnon. | Ketut Subiyanto/Pexels


Alison Hewitt | September 28, 2022

Key takeaways:
• A freak heat wave. Climate modeling suggests the extreme 2021 Pacific Northwest heat wave was roughly a once-in-10,000-years event.
• Climate change link. The heat wave was warmer, and more likely to happen, because of climate change.
• Bad luck. This was an unfortunate combination of nature and climate change, not a sign that extreme heat waves are happening more than predicted.

When the 2021 Pacific Northwest heat wave peaked at 121 degrees Fahrenheit, it buckled roads, melted power lines, killed hundreds and led to a devastating wildfire. Climate scientists were shocked to see heat so severe.

New research by climate scientist and statistician Karen McKinnon shows the scientific community was right to be stunned. The 2021 Pacific Northwest heat wave was roughly a once-in-10,000-years­­ kind of event, the UCLA study found.

“It was outrageous how extreme and severe that heat wave was,” said McKinnon, an assistant professor of atmospheric and oceanic sciences, who is also part of the UCLA Institute of the Environment and Sustainability. “Climate models struggle to capture events this extreme, and most early research puts the chances of it occurring at zero.”

The study appears in the Sept. 28 issue of the journal Geophysical Research Letters. McKinnon, who is also an assistant professor of statistics in the UCLA College, set out to determine two things:

  • whether climate models could establish the probability of such an extraordinary heat wave;
  • whether the extreme heat was a sign that the probability of extreme heat waves is increasing faster than expected.

To find the answers, the researchers analyzed historical trends at weather stations in Washington, Oregon and British Columbia and reviewed climate model simulations. By grouping together international locations that are climatologically similar to the Pacific Northwest, the study found that climate models could simulate heat waves comparable to the 2021 event with a probability of them occurring roughly once every 10,000 years. In cities that experienced the most extreme temperatures during the heat wave, the probability plunged to once every 100,000 years.

Washington state high temperatures map June 28, 21

Temperatures from June 28, 2021, were extremely unusual for the area around Seattle, Washington. | United States National Weather Service


They also found that climate change is increasing heat waves and average summer temperatures at the same pace – so far.

“We don’t see historical evidence of hot temperatures increasing faster than average temperatures during the early summertime when the heatwave occurred,” said McKinnon said. “The 2021 Pacific Northwest heat wave appears to be the result of climate change and extraordinarily bad luck with natural variability.”

The researchers used similar regions to expand their data set, including places like coastal Alaska, all of British Columbia, Canada, and Nordic countries. The regions are in the same northern latitude, generally on the western coasts of continents. They also form heat waves in response to stagnant high-pressure systems, and have similar local climate profiles of positive “skewness” — a lopsided temperature distribution curve with generally mild weather but a history of rare but higher-temperature heat waves.

The researchers analyzed 50 climate model simulations from 1850 through 2100 using a climate model known as Community Earth System Model 2, or CESM2, maintained by the National Center for Atmospheric Research. The simulations assume greenhouse gasses double from current levels by 2100, a plausible emissions future developed by the United Nations’ climate committee and known as SSP3-7.0.

In the simulations, events on par with the Pacific Northwest heat wave were the largest event in 10,000 years of data.

“The good news is that we don’t find evidence that events this extreme should start happening regularly,” McKinnon said. “The bad news is the summer of 2022 brought record-breaking heat waves everywhere from the United Kingdom to China to California. We need to continue evaluating whether these very extreme events are telling us something new about how the climate is changing, and whether they confirm or refute our latest findings.”

McKinnon said that she doesn’t anticipate finding that extreme events are warming faster than average temperatures, but noted that “if 10,000-year events keep happening, that suggests there may be something missing in the climate model we used.” But even if the probability of extreme events keeps perfect pace with average climate change, that’s not good news, McKinnon said.

“If everything’s moving with mean climate change, that can sound like it’s not so bad,” she said, “but look at the severe impacts of the climate change we’re already experiencing.”

That’s part of what drives McKinnon to continue studying large-scale climate variability and climate extremes, as she seeks to understand what’s in store.

The research was supported by the National Science Foundation and the Packard Foundation.


This article originally appeared in the UCLA Newsroom. For more news and updates from the UCLA College, visit college.ucla.edu/news.

First underground radar images from Mars Perseverance Rover reveal some surprises

Unexpectedly tilted rock layers in the Jezero crater hint at a complex geological history

Image of Jezero crater delta

Aerial photo of the remains of a delta where a water source once fed an ancient lake at the Jezero crater. NASA’s Perseverance Rover is currently exploring the area. | NASA/JPL-Caltech/ASU


Holly Ober | August 25, 2022

Key takeaways:

• Roving the Red Planet. NASA’s Perseverance landed on Mars in February 2021 and has been gathering data on the planet’s geology and climate and searching for signs of ancient life.
• What lies beneath. The rover’s subsurface radar experiment, co-led by UCLA’s David Paige, has returned images showing unexpected variations in rock layers beneath the Jezero crater.
• Probing the past. The variations could indicate past lava flows or possibly a river delta even older than the one currently being explored on the crater floor.

After a tantalizing year-and-a-half wait since the Mars Perseverance Rover touched down on our nearest planetary neighbor, new data is arriving — and bringing with it a few surprises.

The rover, which is about the size of car and carries seven scientific instruments, has been probing Mars’ 30-mile-wide Jezero crater, once the site of a lake and an ideal spot to search for evidence of ancient life and information about the planet’s geological and climatic past.

In a paper published today in the journal Science Advances, a research team led by UCLA and the University of Oslo reveals that rock layers beneath the crater’s floor, observed by the rover’s ground-penetrating radar instrument, are unexpectedly inclined. The slopes, thicknesses and shapes of the inclined sections suggest they were either formed by slowly cooling lava or deposited as sediments in the former lake.

Image of RIMFAX subsurface readings

Top: Path of the Perseverance Rover through the Jezero crater. Middle: Subsurface radar image obtained by RIMFAX. Bottom: Diagram indicating where unexpectedly inclined rock layers were located. | Hamran et. al., 2022


Perseverance is currently exploring a delta on the western edge of the crater, where a river once fed the lake, leaving behind a large deposit of dirt and rocks it picked up along its course. As the rover gathers more data, the researchers hope to clear up the complex history of this part of the Red Planet.

“We were quite surprised to find rocks stacked up at an inclined angle,” said David Paige, a UCLA professor of Earth, planetary and space sciences and one of the lead researchers on the Radar Imager for Mars Subsurface Experiment, or RIMFAX. “We were expecting to see horizontal rocks on the crater floor. The fact that they are tilted like this requires a more complex geologic history. They could have been formed when molten rock rose up towards the surface, or, alternatively, they could represent an older delta deposit buried in the crater floor.”

Image of David Paige

David Paige, deputy principal investigator for Perseverance’s RIMFAX instrument. | Courtesy of David Paige

Paige said that most of the evidence gathered by the rover so far points to an igneous, or molten, origin, but based on the RIMFAX data, he and the team can’t yet say for certain how the inclined layers formed. RIMFAX obtains a picture of underground features by sending bursts of radar waves below the surface, which are reflected by rock layers and other obstacles. The shapes, densities, thicknesses, angles and compositions of underground objects affect how the radar waves bounce back, creating a visual image of what lies beneath.

During Perseverance’s initial 3-kilometer traverse, the instrument has obtained a continuous radar image that reveals the electromagnetic properties and bedrock stratigraphy — the arrangement of rock layers — of Jezero’s floor to depths of 15 meters, or about 49 feet. The image reveals the presence of ubiquitous layered rock strata, including those that are inclined at up to 15 degrees. Compounding the mystery, within those inclined areas are some perplexing highly reflective rock layers that in fact tilt in multiple directions.

“RIMFAX is giving us a view of Mars stratigraphy similar to what you can see on Earth in highway road cuts, where tall stacks of rock layers are sometimes visible in a mountainside as you drive by,” Paige explained. “Before Perseverance landed, there were many hypotheses about the exact nature and origin of the crater floor materials. We’ve now been able to narrow down the range of possibilities, but the data we’ve acquired so far suggest that the history of the crater floor may be quite a bit more complicated than we had anticipated.”

Rendering of Perseverance, whose RIMFAX technology is exploring what lies beneath the Martian surface.

Rendering of Perseverance, whose RIMFAX technology is exploring what lies beneath the Martian surface. | NASA/JPL/Caltech/FFI


The data collected by RIMFAX will provide valuable context to rock samples Perseverance is collecting, which will eventually be brought back to Earth.

“RIMFAX is giving us the backstory of the samples we’re going to analyze. It’s exciting that the rover’s instruments are producing data and we’re starting to learn, but there’s a lot more to come,” Paige said. “We landed on the crater floor, but now we’re driving up on the actual delta, which is the main target of the mission. This is just the beginning of what we’ll hopefully soon know about Mars.”

The paper, “Ground penetrating radar observations of subsurface structures in the floor of Jezero crater, Mars,” is one of three simultaneously published papers discussing some of the first data from Perseverance.

This article originally appeared in the UCLA NewsroomFor more news and updates from the UCLA College, visit college.ucla.edu/news.

Picture of Anastassia Alexandrova

Chemist Anastassia Alexandrova receives Max Planck-Humboldt Medal

Picture of Anastassia Alexandrova

Anastassia Alexandrova. Credit: Reed Hutchinson/UCLA

Anastassia Alexandrova, UCLA professor and vice chair of chemistry and biochemistry, has been selected to receive the Max Planck-Humboldt Medal, which honors extraordinary scientists outside Germany with outstanding future potential.

The medal, awarded jointly by Germany’s Max Planck Gesellschaft and the Alexander von Humboldt Foundation, will be presented to Alexandrova in a ceremony in Berlin in November 2022 (delayed one year because of COVID).

Alexandrova and her research team design new materials and develop new algorithms, guided by insights into electronic structure and chemical bonding, using a wide range of methods, including artificial intelligence and machine learning. She and her research team design new catalysts, building up from detailed understanding of their electronic structure, to the shapes, stability and catalytic properties.

She is being honored for her research in theoretical chemistry, in particular her studies on the catalysis of chemical reactions and materials science. Alexandrova has developed methods that simulate how a catalyst behaves during a chemical reaction, which structures mediate between the reaction partners in detail and how the reaction conditions — such as temperature, pressure and concentration of the starting materials — influence the states of the catalyst and this interaction states the press release announcing the medal.

“I am deeply honored to receive the Max Planck-Humboldt Medal,” said Alexandrova, a member of UCLA’s California NanoSystems Institute. “My laboratory is a warm home for students of many different backgrounds, from chemistry and biochemistry to physics, material science and engineering, computer science and applied mathematics.”

Alexandrova is the recipient of many awards and honors, including the American Chemical Society’s 2016 Rising Star Award, which recognizes exceptional women chemists on a national level; a J. William Fulbright U.S. Scholar grant; a 2020 Early Career Award in theoretical chemistry by the physical chemistry division of the American Chemical Society; a 2019 UCLA Distinguished Teaching Award and 2018 UCLA Undergraduate Research Faculty Mentor Award.

This article originally appeared in the UCLA Newsroom.

Picture of Richard Kaner

Richard Kaner wins award from American Chemical Society

 

Picture of Richard Kaner

Richard Kaner, distinguished professor of chemistry and biochemistry, and of materials science and engineering at UCLA.

Richard Kaner, the Dr. Myung Ki Hong Professor of Materials Innovation at UCLA, was selected to receive the 2022 American Chemical Society’s Award in Applied Polymer Science. The award, sponsored by Eastman Chemical Company, recognizes “outstanding achievements in the science or technology of plastics, coatings, polymer composites, adhesives and related fields.” He will be presented the award at the society’s national meeting in San Diego, California, in March.

Kaner, a distinguished professor of chemistry and biochemistry, and of materials science and engineering, is among the world’s most influential and highly cited scientific researchers. Among his many awards and honors, he was elected a 2020 fellow of the American Physical Society and selected as the recipient of the American Institute of Chemists 2019 Chemical Pioneer Award, which honors chemists and chemical engineers who have made outstanding contributions that advance the science of chemistry or greatly impact the chemical profession. He is a member of the California NanoSystems Institute at UCLA.

Kaner and his research team have designed a series of materials. These include creating a membrane that separates oil from water and cleans up the debris left by oil fracking and scaling up a single layer of carbon known as graphene for use in energy storage devices. His research spans a wide range of topics within materials science and inorganic chemistry.

This article originally appeared in the UCLA Newsroom.

Picture of Aradhna Tripati

Climate scientist Aradhna Tripati receives honors from two science organizations

Picture of Aradhna Tripati

Aradhna Tripati. Courtesy of Aradhna Tripati

Aradhna Tripati, an associate professor affiliated with UCLA’s Institute of the Environment and Sustainability and the department of atmospheric and oceanic sciences, has been named recipient of the Willi Dansgaard award from the American Geophysical Union.

Tripati, who is the founder and director of the Center for Diverse Leadership in Science at UCLA, has also recently been elected as a fellow of the California Academy of Sciences. Fellows of the academy are a group of distinguished scientists nominated and appointed in recognition of their outstanding contributions to the natural sciences.

She has been a mentor and advisor to many and has established a number of laboratories. Tripati’s research is focused on using the chemistry of natural compounds as well as models as tools to understand how the Earth works. Her work is relevant to understanding climate change, the oceans, and the transfer of carbon between the biosphere, atmosphere and oceans.

The Dansgaard Award is presented annually and recognizes significant contributions to the fields of paleoceanography or paleoclimatology from a mid-career scientist within eight to 20 years of receiving their doctorate. Named in honor of Willi Dansgaard, a paleoclimate pioneer, this award is presented at the union’s fall meeting.

This article originally appeared in the UCLA Newsroom.

Terence Tao in his UCLA office

Terence Tao named to President’s Council of Advisors on Science and Technology

Terence Tao in his UCLA office

Terence Tao in his UCLA office. Photo credit: Reed Hutchinson/UCLA

Terence Tao, UCLA professor of mathematics, has been selected by President Joe Biden as one 30 of America’s most-distinguished leaders in science and technology who will serve on his President’s Council of Advisors on Science and Technology.

A direct descendant of the scientific advisory committee established by President Eisenhower in 1957 in the weeks after the launch of Sputnik, the council is the sole body of external advisers charged with making science, technology and innovation policy recommendations to the president and the White House to address the country’s most pressing challenges.

Tao, who holds the James and Carol Collins Chair in the UCLA College, became the first mathematics professor in UCLA history to be awarded the Fields Medal in 2006, often described as the “Nobel Prize in mathematics.” He has earned many other honors, including the National Science Foundation’s Alan T. Waterman Award, the Breakthrough Prize in Mathematics, Royal Society’s 2014 Royal Medal for physical sciences, the Royal Swedish Academy of Sciences’ Crafoord Prize and the first Riemann Prize in Mathematics, established by Italy’s Riemann International School of Mathematics. National Geographic magazine featured him in its “What makes a genius?” May 2017 issue.

The new council includes two Nobel laureates, 20 elected members of the National Academies of Sciences, Engineering and Medicine, five MacArthur Foundation Fellows and two former cabinet secretaries.

The council advises the president “on matters involving policy affecting science, technology, and innovation, as well as on matters involving scientific and technological information that is needed to inform public policy relating to the economy, worker empowerment, education, energy, the environment, public health, national and homeland security, racial equity, and other topics,” the White House said.

This article originally appeared in the UCLA Newsroom.

A photo of Aurora borealis in Alaska

‘Surfing’ particles: Physicists solve a mystery surrounding aurora borealis

A photo of Aurora borealis in Alaska

Aurora borealis in Alaska (Photo Credit: Jean Beaufort)

The spectacularly colorful aurora borealis — or northern lights — that fills the sky in high-latitude regions has fascinated people for thousands of years. Now, a team of scientists has resolved one of the final mysteries surrounding its origin.

Scientists know that electrons and other energized particles that emanate from the sun as part of the “solar wind” speed down Earth’s magnetic field lines and into the upper atmosphere, where they collide with oxygen and nitrogen molecules, kicking them into an excited state. These molecules then relax by emitting light, producing the beautiful green and red hues of the aurora.

What has not been well understood is precisely how groups of electrons accelerate through the magnetic field on the last leg of their journey, reaching speeds of up to 45 million mph. In a study published today in the journal Nature Communications, that question is answered by physicists from UCLA, Wheaton College, the University of Iowa and the Space Science Institute.

A popular theory has been that electrons hitch a ride on Alfvén waves — a type of electromagnetic wave that spacecraft have frequently identified traveling Earthward along magnetic field lines above auroras. While space-based research has provided strong support for the theory, limitations inherent to spacecraft measurements have prevented a definitive test.

To overcome these limitations, the physicists conducted laboratory experiments on the Large Plasma Device at UCLA’s Basic Plasma Science Facility, a national collaborative research site supported jointly by the U.S. Department of Energy and National Science Foundation.

After reproducing conditions that mimicked those in Earth’s auroral magnetosphere, the team used specially designed instruments to launch Alfvén waves down the plasma device’s 20-meter–long chamber. Because Alfvén waves are thought to collect only a small portion of electrons in the plasma of space, the physicists focused on determining whether there were electrons that appeared to be traveling at a rate comparable to the electric field of the waves.

“This challenging experiment required a measurement of the very small population of electrons moving down the chamber at nearly the same speed as the Alfvén waves, numbering less than one in a thousand of the electrons in the plasma,” said Troy Carter, a professor of physics and director of the UCLA Plasma Science and Technology Institute.

“Measurements revealed this small population of electrons undergoes ‘resonant acceleration’ by the Alfvén wave’s electric field, similar to a surfer catching a wave and being continually accelerated as the surfer moves along with the wave,” said Gregory Howes, an associate professor of physics at the University of Iowa.

Electrons surfing on Alfvén waves (yellow) streaming toward Earth collide with nitrogen and oxygen molecules (white); in upper altitudes, these collisions result in the emission of red light, while in lower altitudes the emitted light is green.

Electrons streaming toward Earth as they surf on Alfvén waves (yellow) collide with nitrogen and oxygen molecules (white); in upper altitudes, these collisions result in the emission of red light, while in lower altitudes the emitted light is green. (Photo Credit: Austin Montelius, University of Iowa)

Howes noted that these Alfvén waves appear following geomagnetic storms, space-based phenomena triggered by violent events on the sun, such as solar flares and coronal mass ejections. These storms can cause what is known as “magnetic reconnection” in the Earth’s magnetic field, in which magnetic field lines are stretched like rubber bands, snap and then reconnect. These shifts launch Alfvén waves along the lines toward Earth.

And because regions of magnetic reconnection shift during a storm, the Alfvén waves — and their accompanying surfing electrons — travel along different field lines over that time period, ultimately leading to the shimmering glow of the aurora’s curtains of light, Carter said.

In physics, electrons surfing on the electric field of a wave is a phenomenon known as Landau damping, in which the energy of the wave is transferred to the accelerated particles. As part of their research, the team used an innovative analysis technique that combined measurements of the Alfvén waves’ electric field and the electrons to generate a unique signature of the electron acceleration by Landau damping. Through numerical simulations and mathematical modeling, the researchers demonstrated that the signature of acceleration measured in the experiment agreed with the predicted signature for Landau damping.

The agreement of experiment, simulation and modeling provides the first direct test showing that Alfvén waves can produce accelerated electrons that cause the aurora, Carter said.

“This experimental confirmation of the physics behind the aurora is due to persistent ingenuity of research groups at the University of Iowa and UCLA,” said Vyacheslav (Slava) Lukin, program director for Plasma Physics at the National Science Foundation, who was not involved in the research. “From student support via an NSF Graduate Research Fellowship, to the NSF CAREER program for early career faculty, to the 25-year partnership between NSF and the Department of Energy that has enabled the unique capabilities of the Basic Plasma Science Facility, this is a success story of a discovery made possible by consistent support of the university research community.”

In addition to Howes and Carter, study authors included James Schroeder of Wheaton College, Craig Kletzing and Frederick Skiff of the University of Iowa, Stephen Vincena of UCLA, and Seth Dorfman of the Space Science Institute.

Further information on the research findings is available on Howes’ website.

This article originally appeared in the UCLA Newsroom.