Taking Satellite Technology—and Physics—to New Heights

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Category: Department News

Published: Sunday, September 05 2021 00:11

Jim CarrJames Carr (Ph.D. ’89, physics) has been making his mark on satellite technology for more than three decades. But his passion for space launched long before his professional career did.

“I grew up in the days of the race to the moon and I was very drawn into that,” he recalled. “I followed all of the Apollo missions. In fact, I used to pretend I was sick and couldn’t go to school so I could watch the coverage on the networks. I was very interested in the space program and that carried forward into what I ended up doing professionally.”

Today, Carr is president and CEO of Carr Astronautics. For more than 30 years, the company has provided problem-solving technology and expertise to clients in the aerospace industry, specializing in U.S. and international weather satellites.

A running start

Carr got a running start on a future in physics and space technology as a boy growing up in Pittsburgh, Pennsylvania. At home, science was part of life. Carr’s first mentor was his father, a scientist who authored two books and more than 100 scientific papers and received a dozen patents during his professional career.

“My father worked at Westinghouse Research Labs; he was a physicist,” Carr explained. “Back in that day, we called it solid state physics, now we would call it condensed matter. So, I grew up surrounded by those environmental influences.”

When it was time for college, Carr stayed close to home and, like his father, was attracted to physics and mathematics. He got his undergraduate degree at Carnegie Mellon University, then headed to Washington, D.C., to join his wife who had already graduated.

“She was a software engineer and she came down to Washington, D.C., because that’s where the jobs were,” Carr said. “She found a job with IBM in the Washington suburbs.”

Carr landed a position working on military projects with a D.C.-area company, but his longer-term sights were set on a very different mission.

“I wanted to work with NASA”

“I had a tremendous first job and I really enjoyed it,” he recalled. “But I wanted to be involved in more civilian things, what you’d call space exploration. I wanted to work with NASA.”

Within three years, Carr was working at NASA’s Goddard Space Flight Center in Greenbelt, Maryland, doing the kinds of projects he once dreamed about. Much of his work focused on remote sensing—processing and analyzing data collected in space, especially weather data.

“I started out helping out on various programs—science experiments that were flying on the space shuttle,” Carr explained. “Then I got involved in a program called Landsat. I was helping NASA integrate all of the work from the different contractors that were contributing to the program and then developing algorithms for processing the data on the ground.”

In 1983, Carr got his master’s degree in physics at Georgetown, while still working at NASA. By then, he was involved in a new operational weather satellite program called GOES (Geostationary Operational Environmental Satellite).

Ground zero for GOES

“When I got on the GOES program, it was sort of ground zero and it was new and there were a lot of problems to figure out,” Carr said. “It was a more challenging and fun environment to work in than some of the projects I’d done before and I really enjoyed it.”

Later in 1983, Carr decided he was ready for a very different kind of challenge. He applied to the University of Maryland’s physics Ph.D. program.

“I wanted to have a big impact on science and there were a couple of courses at Maryland that really brought me into particle physics, which is not what I did at NASA,” he explained. “I decided that was where the really exciting frontiers of physics were so I should go all in.”

Carr’s years at Maryland, and especially his work with the particle physics theory group, made a life-changing impact.

“Oh yeah, there’s no question, I consider my time in the physics department at Maryland to be formative,” he said. “It was important for my formation as a professional person, very key, a very positive experience.”

Carr was inspired and influenced by his thesis advisor, S. James Gates Jr., who is now a College Park Professor of Physics at UMD.

“He was a young faculty member at the time, and I was drawn to him because of he was working at the frontiers of physics,” Carr recalled. “His energy and enthusiasm were compelling, and as I got to know him, I found him to be as fine a human being as a physicist—very supportive of the intellectual and professional growth of his students.”

After receiving his doctorate in 1989, Carr had an important career choice to make. He could keep working at NASA or pursue a postdoc and a career in academia.

The offer that launched a company

Carr decided to stay at NASA, but his entrepreneurial side was pushing him to do something more.

“I saw the companies that were doing work with NASA and I didn’t understand why I couldn’t run one of those companies myself,” Carr explained. “I decided that I would do it, that would be my career path. I would continue working in the NASA community and I would look for an opportunity to start a business.”

That opportunity came in 1991.

“It happened when I was presenting a paper at a conference about the work I was doing with GOES,” Carr recalled. “I was approached by some people from Europe who proposed that I come to work for them as a consultant to help them in a program called Meteosat Second Generation, which was similar to the American GOES weather satellite I’d been working on for NASA.”

That offer launched Carr Astronautics. Though Carr was the company’s only employee, he had his first client—the French aerospace manufacturer Aérospatiale—and his first project, the Meteosat Second Generation weather satellite. Carr moved his family to Cannes, France, where he worked on Meteosat for the next five years. After they returned to the U.S., Carr’s company took off.

“I came back to the U.S. in ’96 and at that time I was acquiring other business at NASA and also at NOAA and we just continued to grow,” Carr said. “I hired some people that I had known from working with them at NASA and I started working with some American aerospace companies like Boeing Corporation.”

In the decades that followed, Carr Astronautics built a track record of success in satellite technology.

“One of our templates for success has been to partner with large aerospace companies like Boeing and Aérospatiale and help them design their satellite systems. These are billion-dollar space systems and it takes a giant team of engineers to design them, and we have niche expertise,” Carr explained. “The other thing we do is we build software systems to transform the raw data that comes from the spacecraft into something that is scientifically sound and is consumable by the weather community including the National Weather Service.”

And the work is far from over. By 2023, a SpaceX Falcon 9 rocket will launch the Intelsat communications satellite, and with it an air pollution-sensing instrument that Carr Astronautics has worked on for years. The instrument, called TEMPO, is an imaging spectrometer designed to detect trace gases—including pollutants like nitrogen dioxide, sulfur dioxide and ozone—by the “fingerprints” they leave in the sunlight reflected off Earth’s surface.

“TEMPO will allow us to understand how the rhythms of human activity affect our environment hour by hour,” Carr said. “It will be part of a constellation of similar sensors to cover North America, Europe and Asia.”

Honoring his first mentor

Through all his professional growth and success, Carr has always appreciated the impact his very first mentor—his father—had on his life. And, in 2007, he found a way to pay it forward. Working with UMD, he established the W.J. Carr Lecture Series on Superconductivity and Advanced Materials in the Department of Physics to honor the man who introduced him to physics.

“My father passed away and we started this before he passed,” Carr explained. “I wanted to memorialize him in some way, and I thought this was a good thing to do.”

Carr’s endowment supports an annual lecture series that brings eminent physicists to College Park to speak and interact with students in UMD’s physics program and Quantum Materials Center.

“They’ve brought in really top people to talk, and typically they stay for a week, doing seminars and lectures and collaborations,” he explained. “I think my father would have liked that.”

It’s been more than 30 years since Carr turned his passion for space into a successful business, advancing the technology of weather forecasting one satellite at a time. Still energized by the work, he’s glad he’s been able to make a difference.

“I am very proud of what we do,” he reflected. “The weather affects us in very big ways with hurricanes and tornados and droughts and in very small ways with the decisions we make every day. So it’s extremely important to have good information and good forecasts. I find it very gratifying that the work that I’ve done—the satellite technology—has provided a foundation for all of that.”

Written by Leslie Miller

Junior Kate Sturge Discovers Love for Research—and Experimental Particle Physics

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Category: Department News

Published: Friday, September 03 2021 00:11

Kate Sturge knew one thing for sure when she began her freshman year at the University of Maryland: she loved physics. So, when she received an email inviting her to apply for the First-Year Innovation and Research Experience (FIRE) program, she immediately searched for an option that would allow her to do physics research.

The junior physics and astronomy dual-degree student ultimately selected the Simulating Particle Detection (SPD) stream—one of FIRE’s 15 groups that offer first-year UMD students a faculty-mentored research experience. Over three semesters, students build knowledge and research skills and complete a research project. The SPD stream introduces students to the field of experimental particle physics through simulation of high-energy particle detectors.

“My interest in experimental particle physics deepened as I went through the FIRE program,” said Sturge, whose dad is a high school physics teacher. “As I learned how excited and passionate high-energy physicists are about their work, I found that type of enthusiasm was contagious—and I caught the bug.”

The field of experimental particle physics explores fundamental forces and particles—building blocks of the universe. The Large Hadron Collider (LHC), located at CERN near Geneva, Switzerland, is the world’s largest and most powerful high-energy particle accelerator and collider designed to examine these particles. One experiment attached to the LHC is the Compact Muon Solenoid (CMS), a general-purpose detector that observes any new physics phenomena that the LHC might reveal, including particles that could make up dark matter.

The CMS detector is currently undergoing an upgrade for higher luminosities, which requires simulation modeling for improved design and performance. That’s where the UMD CMS Experimental High Energy Physics group—and FIRE SPD students like Sturge—come in.

“Our topic is quite cool. My students are doing data analysis of a simulation for the detector that is being built and designed as we speak. And it’s going to be 100 meters underground in France on the border of Switzerland in five or six years,” said Müge Karagöz, assistant clinical professor in the Department of Physics and faculty leader for FIRE SPD. “All my students are doing something related to that particle detector’s computational simulation efforts, from data analysis and visualization to design performance and optimization.”

The SPD stream attracts about 30 students per year from various disciplines. In addition to the three-semester general education curriculum, FIRE students can participate in a summer program to further develop their research and leadership skills.Kate Sturge

During the summer program in 2019, Sturge attended the US CMS Annual Collaboration Meeting in Washington, D.C., where she met a researcher from Fermilab who was also working on the CMS experiment. He shared a project that would be a good fit for undergraduate researchers with the SPD stream—using computational analysis to study “mousebites” in one of the subdetectors on the CMS detector upgrade.

Sturge decided to take on this mousebite project as a peer research mentor, continuing to advance her research skills while mentoring incoming students.

“In the High Granularity Calorimeter, or HGCAL, the sensors are hexagonal wafers, and within those wafers are smaller hexagonal silicon cells. When a particle passes through the sensors, the hexagonal cells measure the energy that a charged particle produces,” Sturge explained. “In the corners of the hexagonal wafers, the tips have to be cut off to mount the hexagons to each other. You essentially have little gaps in the detector where no signal can be produced because of the little pieces of metal that screw the wafers to each other. Those little pieces of metal are called mousebites.”

After spending the fall 2019 and spring 2020 semesters working on the mousebites project, Sturge helped quantify the energy degradation caused by the mousebites and concluded that it would not have a significant impact on the overall function of the detector.

Staying on with the UMD CMS Experimental High Energy Physics group in summer 2020, Sturge joined a project with Physics Professor Sarah Eno and Ph.D. student Christos Papageorgakis. There, Sturge’s research experience was an asset.

“Because of her FIRE experience, Kate came to me with a much bigger toolbox of skills related to physics simulations than a typical undergrad starting a research project with me might have,” Eno said. “She was able to quickly come in and help us understand more about the resolution of the calorimeter we are helping to build by 2025.”

The hexagonal sensors on the HGCAL that Sturge previously examined for her mousebites project are constantly bombarded with charged particles, which could lead to radiation damage—and dead cells—over the course of the detector’s lifetime. Sturge built on her mousebites research and worked with Eno and Papageorgakis to determine whether this cell damage would impact the long-term function of the CMS detector.

“I simulated the effects of those dead cells and then used deep neural network machine learning to correct for that damage,” Sturge said. “The deep neural network takes a dead cell’s 20 closest neighbors and outputs a value for the reconstructed energy of the dead cell. We found that we can actually bring the energy resolution very close to what it should be in the ideal case with no dead cells.”

According to Eno, the deep neural network Sturge developed will be used to improve the calorimeter’s performance once the team commences data collection. Sturge and Papageorgakis drafted a “CMS note,” which is a detailed internal document of the CMS detector collaboration. This document is used by 3,000 physicists worldwide who are preparing publications and upgrades for the detector.

With these two research projects under her belt, Sturge was selected for a prestigious internship with CERN in summer 2021, where she worked on the Atlas experiment and learned about different processes and codes related to the LHC.

“I have really enjoyed the opportunities to challenge myself and learn skills that aren’t taught in traditional physics courses,” Sturge said. “It’s meant a lot to me to get to see what I can do given the tools and resources to succeed.”

Looking ahead, Sturge’s goal is to work in computational high-energy physics research.

“Being able to recognize a pattern through computational analysis is really powerful and exciting,” Sturge said. “Even the grunt work that goes with it, going through and debugging, the grueling hours of trying to find why your code won’t run—I’ll even find that I sit down at my computer and look up, and five hours have gone by. It’s just something that I genuinely enjoy doing.”

Written by Katie Bemb

John Mather Looks to the Past and Keeps Moving Forward

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Category: Department News

Published: Friday, September 03 2021 00:11

John Mather Credit: NASA/Chris GunnThe past contains lessons that cannot be learned in the present. And although the past is often like a hazy crystal ball that is challenging to interpret, it is still instructive if we want to understand ourselves and our position in the universe.

To understand the origins of our universe, cosmologists piece together the subtle, lingering clues of a past that predates humanity as well as Earth. To do so, they must look past our local galactic neighborhood and study distant parts of the universe that might be forever beyond humanity’s reach.

John Mather, a College Park Professor of Physics at the University of Maryland and a senior scientist at NASA, has pursued his curiosity about the origins of the universe and succeeded at peering into the furthest reaches of the past, earning a Nobel Prize along the way.

“We can't see the Earth's history,” Mather said. “But we can see examples way out there. So what happened to make it possible to go from the Big Bang to Earth? We have a story of how that would happen. But most of it’s made up—most of it’s imaginary. So we have to check it by actually looking.”

Later this year, Mather will add a new chapter to his storied career. After decades of work, NASA is launching a revolutionary instrument into space, the James Webb Space Telescope—and Mather is the senior project scientist. The Webb telescope is bigger than the Hubble Space Telescope or any other telescope ever launched. It has about 6.25 times more area dedicated to collecting light than the Hubble, and it is designed to reveal for the first time sights of the primordial formation of some of the earliest stars and planets in the universe. Mather has spent the last quarter of a century helping make this ambitious project a reality.

The Dazzling Past

Mather shared the 2006 Nobel Prize in physics for uncovering secrets in the ancient, invisible remains of some of the universe’s first light, captured using the NASA Cosmic Background Explorer (COBE) satellite. This primordial light is called cosmic microwave background radiation and is constantly bombarding Earth (and every other part of the universe) from every direction. The ancient light is a dim but persistent messenger from that long-gone age, and it provides a unique window into the universe’s earliest moments.

COBE revealed that this radiation was a cosmic fingerprint with subtle variations. And that fingerprint proved to be the vital clue needed to establish the Big Bang theory as the accepted explanation for the birth of our universe (although Mather isn’t fond of the firework imagery summoned by that name for the beginning of an expanding, infinite universe).

Scientists think that the uneven pattern observed in the radiation resulted from the early universe being hotter and denser in some areas than others. This revelation is researchers’ main lead as to why matter ended up clumping together into stars, planets, galaxies and all the other objects that fill our universe. Those initial hot and cold pockets were the first dominoes that led to Earth and the rest of the dynamic universe we see today.

Reflecting on his fruitful career, Mather said that he thinks successful science, like the COBE mission, is the result of teamwork, a little bit of luck and pursuing your curiosity despite adversity.

For instance, COBE grew directly out of some of Mather’s graduate work that delivered disappointing results. He and his colleagues first tried measuring the cosmic background radiation from White Mountain in California. They learned a little bit about the radiation, but the tumultuous atmosphere prevented them from seeing details that could tell them about the early universe.

So they tried even greater heights—literally—by sending the measurement equipment up 25 miles using a balloon. The first flight failed to produce any results, and the next attempt didn’t happen until after Mather graduated. When the balloon-borne equipment finally managed to successfully collect data, it still lacked the desired precision.

Despite these troubles, the idea stuck in Mather’s head, and the project unexpectedly got a new life when NASA called for proposals for satellite experiments in 1974, just five years after the Apollo landing.

“I said, ‘Boss, my thesis project failed, we should try it in outer space,’” Mather said. “So he said, ‘We'll write a proposal.’ And that kept on not losing. At every possible place where you could be stopped, we found a way to keep on going. So 15 years later, it was launched.”

The data collected by COBE finally revealed the subtle details needed to interpret the radiation and left Mather and the rest of the scientific community with plenty of work to do. Those early hot and cold spots are just part of the story of the origin of everything.

Mather continued to investigate the origins of the universe and, in 2011, became an adjunct professor at UMD in addition to working at NASA. His current work is still unraveling the mystery of what the formative years of the universe looked like, and this time, with the help of a massive team, he hopes to get a look at the formation of some of the earliest galaxies.

An Unfolding Story

Mather recalled getting started on the Webb telescope with a call in 1995 asking if he wanted to work on a new telescope project that NASA was considering.

“Of course, I said, ‘Yes, that would be the coolest thing.’” Mather said. “And so that's what I've been doing ever since.”

Mather and his colleagues developed a plan for a telescope to observe things that are invisible to COBE, Hubble and every other satellite ever launched. The goal is to see more than 13.5 billion years into the past (when the universe was only about a couple of hundred million years old) and to take baby pictures of our universe that show the formation of the earliest galaxies and how they birth stars.

“One of the great mysteries is what was it like back then,” Mather said. “And we've never been able to see. The telescopes that we have are not powerful enough and do not observe at the right wavelength. So you just can't tell.”

The Webb telescope will gaze into that distant past by collecting light that is mostly invisible to the human eye. Light travels as waves of electric and magnetic fields, and the color of the light is determined by the distance between the wave peaks. The Webb telescope will look at the longest light waves humans can see—red—and the invisible light that is even more stretched out—infrared. (Infrared light is given off by human bodies and many other objects and is what night vision goggles detect.)

These long waves interest cosmologists because the universe is expanding, and as it expands, it also stretches out light. Light that starts out as blue (the shortest light we see well) gradually becomes yellow and then red and eventually infrared (and continues getting stretched into even longer, harder-to-detect wavelengths). Any light that has been traveling for billions of years since the birth of early galaxies has had plenty of time to stretch out.

We can’t see the past of our own corner of the universe, but by collecting and interpreting this stretched light, we can see the past of the far-distant part of the universe that the light came from.

The Webb telescope will be a revolutionary tool in observing the ancient and distant universe to check if our theories about that primordial time are correct. It is a big project that goes beyond the efforts of just NASA. The mission is a collaboration with the Canadian Space Agency and the European Space Agency and involves scientists from 14 countries, 29 U.S. states and the District of Columbia.A full-scale model of the James Webb Space Telescope being constructed at Battery Park in NYC for the 2010 World Science Fair. (Credit: NASA)

As the Webb telescope’s senior project scientist, Mather works with other scientists to identify what the telescope needs to do to make new discoveries and then works with engineers and managers to turn those grand visions into reality.

“I am at the interface between two worlds, and it's a very interesting place to be,” Mather said. “Of course, the work is really done by the participants saying, ‘Well, this is what my idea is,’ and somebody else says, ‘Well, I have a different idea.’ And then we have another idea. And then we have discussion, and maybe a little bit of hand-to-hand combat. Sometimes actually, instead of hand-to-hand combat, we have a vote, but that's not usually done, because usually it's pretty clear what is needed.”

This back-and-forth has been a lengthy process. By 2009, 14 years after Mather got involved in the project and five years after construction started, NASA targeted a launch date in 2013. But the project has suffered repeated delays. Technical difficulties with the telescope and complications from the COVID-19 pandemic contributed to recent delays. Now, the long-awaited launch is looking promising for the end of 2021.

“There's an awful lot of translation from the wish into a plan,” Mather said. “The Webb has taken about 25 years since that first phone call that I got. And most of that wasn't building; most of that was deciding what to build. When you're reaching so far beyond where anybody has ever been, you can't just draw a sketch and say, we'll build that. You have to say, ‘This is the set of inventions that we require, please go make those inventions, and then we'll decide something.’ So that took a good, long time just to even get started on the inventions.”

The team’s work includes making the telescope capable of maintaining a difference of 600 degrees Fahrenheit between the parts most heated by the sun and the coldest instruments with cooling systems and a tennis court-sized parasol. The giant parasol (or as NASA calls it, a “sunshield”) and a gold-covered mirror that is more than 21 feet across are made to fold up like origami for the rocket launch and then to unfold in space.

The team’s inventions and clever solutions combine into a telescope expected to be good enough to detect the amount of heat given off by a bumble bee from as far away as the moon is from Earth. All of the technology is designed to be deployed about a million miles from Earth (about 4 times farther from Earth than the moon). If everything goes according to plan, it will take about six months from launch to get the telescope into location, set up, tested and ready to perform science.

A Promising Future

The Webb telescope will let scientists do more than peer into the early history of the universe, though. Infrared light should let them peek into cosmic dust clouds that block visible light and study the formation of stars and planets that are not too far from our solar system (which formed more recently). It might even reveal new details of neighboring celestial objects like the moons of Saturn or the dwarf planet Pluto. It will also be able to detect water vapor and other chemicals in the atmospheres of planets outside our solar system.

Researchers from all over the world have the chance to suggest how to best use this technological marvel. Of the proposals selected for the first year of the telescope’s observation, about 10% came from students. Just as Mather’s proposal for the COBE satellite launched his success, other stellar careers might take off with this new telescope.

Mather said he is proud that the Webb telescope mission is providing opportunities to early-career scientists. And despite the Webb telescope keeping him busy at NASA’s Goddard Space Flight Center in nearby Greenbelt, Maryland, he still values his connection to the university.

“We have a pretty strong connection between NASA Goddard and the University of Maryland,” Mather said. “Especially, we cooperate in high-energy physics, astronomy, cosmic rays, X-rays, gamma rays and things that people at the university have a lot of expertise in. I'm glad to be a member of the department. And I look forward to talking with people that I have shared interests with. I invite people to contact me about the Webb telescope and about any other ideas that they have, especially for space astronomy.”

The best advice Mather says he can offer students is just telling them what worked for him. He credits his success to finding people he liked to work with and persistently tackling interesting questions with them despite setbacks.

“I can't say that setbacks are fun,” Mather said. “But in our business of science, they're all the time. Treat failures as setbacks and learning opportunities and think about what else you would do next. While I was working on the balloon payload, I had in the back of my mind, ‘Well, the problem with this balloon is that it's not in outer space.’ And when NASA asked for proposals, I said ‘Well, I've got an idea.’ So when a good idea comes to you and you can't do it now, keep it. And maybe you'll get a chance later. The future is long. Probably infinite.”

Written by Bailey Bedford

Elevating the Humble Neutrino

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Category: Department News

Published: Friday, September 03 2021 00:11

Rabi Mohapatra at the 2016 campus convocation

Rabindra Mohapatra wants “neutrino” to be a household word.

“This is a very fascinating particle,” he said. “Neutrinos are so tiny, there are billions of them passing through us every second, and they interact so weakly, we even can’t tell. But the neutrino is pretty much responsible for creating the whole universe, everything we see has an imprint of the neutrino.”

Mohapatra, a Distinguished University Professor of Physics at the University of Maryland, has been theorizing the origins and mass of neutrinos for 40 years. Last fall, he published a book targeted toward non-scientists called “The Neutrino Story: One Tiny Particle’s Grand Role in the Cosmos.”

As a theoretical physicist, Mohapatra proposes mathematical explanations for how the universe works, specifically how the tiny particles that make up the universe and the forces that control them interact to create all the matter we can see—and even the dark matter we can’t see. It may seem like heady stuff for a village boy from India, but Mohapatra’s path followed a logical trajectory for someone in his shoes.

“I was always interested in science, from the very beginning,” he recalled. “But we didn’t have too many instruments to work with in my school, so experimental physics was not the way I could go to explore my interests. Mostly then, my interests became theory based, and I studied math and science books.”

Mohapatra was especially inspired by popular science books like “One Two Three . . . Infinity,” which was written by Russian theoretical physicist and cosmologist George Gamow, who helped develop the Big Bang theory.

“One of the things that inspired me quite a bit from Gamow’s books and other popular science books was learning that something so abstract as mathematical formula could be connected to the simple things we observe,” Mohapatra said. “And my father sort of pushed me in that direction, too, because he was very interested in math. In fact, my father had gone to college, which was quite an amazing thing in the 1930s.”

The younger Mohapatra earned his bachelor's degree in physics in 1964 from Utkal University in Bhubaneswar, India, and his master's degree in physics at the University of Delhi in 1966. The same year, he traveled around the globe to New York where he earned his Ph.D. in physics at the University of Rochester in 1969.

After completing postdoctoral fellowships at Stony Brook University and UMD, Mohapatra joined the physics faculty at City University of New York. In 1983, he returned to the Department of Physics at UMD as a professor, and he has been here ever since.

Over his career, Mohapatra has traveled the world for conferences and talks. He accepted multiple visiting professorships at institutions like the Max Planck Institute for Physics and the Technical University of Munich in Germany, CERN in Switzerland, and Los Alamos National Laboratory and Brookhaven National Laboratory in the U.S.

Mohapatra is known throughout the world for his seminal theories on neutrino masses, which include support for new particles and a unifying theory that governs the behavior of all matter in the universe. Along the way, he has published 450 peer-reviewed research papers and received numerous awards such as the Distinguished Scientist Award from the American chapter of the Indian Physics Association in 2000 and the prestigious Humboldt Prize in 2005.

At UMD, Mohapatra was awarded a Distinguished Faculty Research Fellowship in 1995-96 and was named a Distinguished Scholar-Teacher in 2000. In 2016, he was honored with the title Distinguished University Professor, the highest academic honor bestowed by the university.

And yet, Mohapatra says some of his proudest accomplishments are those in which he passed on his passion and expertise to young scientists.

“I feel fortunate to have worked with them,” he said of the 25 Ph.D. students he mentored at the City University of New York and UMD. “They have been really inspiring. Many of them are now faculty members at universities all around the world, and that’s one of the most satisfying things about my career.”

Although Ph.D. students invigorate Mohapatra’s scientific mind, he also finds joy in sharing his enthusiasm with students who come to him with no knowledge of his field. This joy drives him to teach large introductory physics lecture courses.

“They’re usually a lot of work because they’re such large classes,” he said. “I like to teach them because it’s a way to communicate with younger people who have some of the most interesting ideas. I try to sneak in some of these higher concepts and get them thinking about these things, and hopefully some of them grab on to it.”

That same desire to reach a broader audience is what motivated him to write his latest book as well. Mohapatra had already written a textbook on supersymmetry and co-authored another on neutrino masses, which have both gone on to third edition printing. But he was encouraged by his wife to write a book that would inspire science enthusiasts in high school or college to appreciate the beauty and significance of neutrinos.

But it was a challenge. The seminal theories Mohapatra is most known for and spends much of his time working on can be a little mind-bending to the average person.

In his theories of left-right symmetry, for instance, Mohapatra tackles a long-standing question about why certain particles only appear to have one of two known presentations in certain circumstances. The presentation in question is known as right- or left-handedness and refers to the direction in which a particle spins relative to the direction it is moving.

For example, if you make a “thumbs up” gesture, in which your hand is a particle, your thumb indicates the direction the particle travels, and the curl of your fingers indicates the direction the particle spins. A right-handed “thumbs-up” is the mirror image of a left-handed one. And for some unknown reason, physicists only see left-handed neutrinos.

Where it gets complicated is in the search for the left-handed neutrino’s anti-matter particle. Every elementary particle has an anti-particle that has the same mass and spin but opposite charge (or in the case of neutrinos, which are electromagnetically neutral, the anti-particle has an opposing lepton number.)

Scientists have yet to observe a left-handed anti-neutrino, the counter particle to the left-handed neutrinos they’ve seen. However, they observed anti-neutrinos, but they’re all right-handed. This breaks the mirror symmetry of nature, but Mohapatra believes the problem is a matter of scale. He hypothesizes that all particles, including right-handed neutrinos and left-handed anti-neutrinos, do exist in nature. We just can’t see the right-handed neutrinos now because they are very heavy and show up at a higher energy scale.

“Meaning, at some higher energy scale, everything has symmetry between left and right, but when we come to the scale we can observe and we do an experiment involving the neutrino, things look only one-sided, where we only see the left side and not the right,” he said.

Experimentalists have been working on testing these theories, and their observation of neutrino mass provides some indications that Mohapatra could be correct.

Another one of Mohapatra’s ideas that experimental physicists are working hard to understand is called the seesaw mechanism for explaining neutrino mass.

Physicists have long pondered how neutrinos can have so little mass. (They are a billion times lighter than protons.) Mohapatra proposed that the right-handed neutrino that has yet to be observed acts as the right-handed neutrino’s heavy, unseen partner.

“It’s a bit like a seesaw on the playground,” he said. “When one child goes up, it is because another heavier child is sitting on the other side. So, the idea is that if there is the heavy right-handed neutrino sitting on the other side of the world in some sense, then this particle, the neutrino we see, becomes light. It’s not a very clear explanation but that’s probably the best one can do.”

Of course, that may be all one can do in a sentence. Mohapatra draws a clearer picture of the seesaw mechanism in his new book, which hit the shelves in November 2020. By September 2021, it was already selling well as Amazon reported just 10 left in stock, with more in print. That’s not a bad start for someone on a quest to make “neutrino” a household word.

Written by Kimbra Cutlip