Jamie Rankin

Jamie Rankin

Ed Stone, 1986

The Voyager spacecraft captured the public imagination in the 1970s and ’80s as Earth’s first ambassadors to the outer planets.

Early career Princeton astrophysicist Jamie Rankin, BS'11 Physics and BA'11 Music Composition, is now playing a leading role on the Voyager team that continues to track the aging probes, each more than 10 billion miles from Earth.

In many ways, the Voyager twins are time capsules of their era. They both carry an eight-track tape player for recording data, they have 3 million times less memory than modern cellphones, and they transmit data about 40,000 times slower than a 5G internet connection. They both have a Golden Record: a message from humanity to the cosmos with greetings in 55 languages, pictures of people and places on Earth, and music ranging from Beethoven to Chuck Berry’s “Johnny B. Goode.”

In recent decades, the missions have made few headlines, but the little spacecraft have continued voyaging outward under the leadership of Project Scientist - Ed Stone. Despite their now-archaic memory and transmission systems, the Voyagers remain on the cutting edge of space exploration as the only instruments to ever travel through interstellar space.

Linda Spilker

After Stone’s recent retirement, Linda Spilker, who has been involved with Voyager since 1977, stepped into Stone’s shoes, and Rankin was selected to be the Voyagers’ deputy project scientist.

Only 34 years old, Rankin is one of the youngest researchers ever to hold such an elevated title.

Nicola “Nicky” Fox, director of NASA’s Heliophysics Division, oversees all solar and heliosphere missions for NASA and participated in selecting Rankin as Voyager’s second-ever deputy project scientist.

“Jamie is an absolute rock star,” Fox said. “I think it’s really important that when you see somebody who’s got that much talent, that can do really amazing things, that you give them opportunities.”

Nicky Fox

“Voyager is an amazing mission, and I’m so grateful for this opportunity,” said Rankin, who is an associate research scientist at Princeton and an instructor of the space physics laboratory class. “I am only here because I had so many professors and mentors who believed in me; I never expected to make it to a place like Princeton.

I can’t overstate the importance of mentorship. I love teaching students, and giving them opportunities with NASA space flight instrumentation, because I’m so thankful for the opportunities I’ve been given.”

Rankin was Ed Stone’s last graduate student at Caltech. He had sworn some 25 years before that he wouldn’t take any more grad students, but Rankin lobbied him relentlessly until he took her on.

“I did the first thesis on Voyager’s data from interstellar space,” Rankin said. “I arrived at Caltech six days after Voyager 1 reached interstellar space, so I got to see that whole history unfold. I entered in thinking about Voyager completely from the interstellar perspective, which was very different than anybody else on the Voyager team, most of whom have been with the mission since the beginning.”

Ed Stone, 2019

Voyager’s next generation

“When I walked into the Voyager team room, my first day as a graduate student, I noticed there was at least a three-decade age difference between me and the youngest person in the room,” Rankin said. “And when I started as a graduate student, there was a 50-year age difference between me and Ed. We skipped a generation there."

"But what’s really neat about it is that for future space missions, if people want to send an instrument very far away, they absolutely have to have a multi-generational team. With the Voyagers, they just didn’t know; no one anticipated the mission surviving this long.”

Two years after their 1977 launch, the twin probes flew by Jupiter, beginning the planetary encounters for which Voyager is best known. Both spacecraft visited Jupiter and Saturn, then Voyager 1 headed out of the solar system while the slightly slower Voyager 2 headed on to Uranus and Neptune.

All the planetary encounters were over within 10 years, and on Jan. 1, 1990, the Voyager Interstellar Mission officially began — even though the Voyagers wouldn’t technically be in interstellar space until they exited the heliosphere, the bubble of space around our sun.

Jamie Rankin, 2020

Two quiet decades after leaving behind the outer planets, Voyager 1 crossed the heliopause in August 2012. Its slower twin crossed that boundary six years later, in November 2018.

Mapping the edge of the solar system

“This is just an incredible time to be studying the outer heliosphere,” said NASA’s Fox. “For the first time, we have a lot of assets focused on the outer heliosphere.”

Fox cited the IBEX mission, headed by McComas, which has spent years imaging the outer edge of the solar system; New Horizons, which has long passed Pluto and is closing in on the termination shock; IMAP, also headed by McComas, which will map the heliosphere in detail; and of course the Voyagers, the only spacecraft ever to venture so far away from our sun.

“The science still coming from the Voyagers is amazing — and underappreciated,” said Rankin. “Everything — everything — that we’ve measured in space gets filtered through the solar wind — through the sun and its plasma and magnetic fields. And everything measured from Earth-based telescopes is also filtered through our atmosphere.

The Voyager spacecraft

“The very first time that we could measure space directly, without being disturbed by the sun, was when Voyager crossed into the interstellar medium.”

One thing Voyager measured was the level of incoming radiation, which was almost 10 times higher outside the heliosphere than inside the bubble. That radiation could pose a deadly threat to astronauts, but the Voyagers showed that the sun, via the solar wind and heliosphere, is filtering out as much as 90% of the interstellar radiation.

“The solar wind is actually protecting us,” Rankin said. “Before the Voyagers got out here, nobody knew quite how much we were being shielded.”

The Voyagers also discovered that the sun interacts with its boundary differently than scientists had expected. “When two magnetized plasmas meet, it’s like north-north magnets — they can’t ever mix,” Rankin explained. “So the solar plasma, the solar wind, can’t mingle with the interstellar plasma. But there are also neutral particles out there that aren’t electrified, so they don’t care, they just pass straight through the heliospheric boundaries, unaware. Eventually those do have an influence on our solar environment, and our environment can have an influence on them.” Although the Voyagers are not equipped to measure these neutral particles directly, other missions, like IBEX and New Horizons have provided complementary insights about the nature of these unique interactions throughout the heliosphere.

When IMAP launches in 2025, it will map out that elusive boundary zone in great detail, providing a comprehensive picture to complement the deep but geographically limited data that the two Voyagers have collected.

What does a project scientist — or her deputy — do?

NASA’s enormous array of spacecraft missions generally fall into two categories: Smaller missions that are run by a single principal investigator (nearly always shortened to PI), and larger missions that have PIs for each of their instruments. David McComas, for example, in addition to being Princeton’s vice president for the Princeton Plasma Physics Lab and a professor of astrophysical sciences, is the PI for many missions and instruments, including both the IBEX and IMAP missions and the ISʘIS instrument suite on the Parker Solar Probe.

David McComas

The large missions have a project scientist (and sometimes a deputy) to coordinate the mission’s many-fold research endeavors, to make sure the different instrument PIs don’t become too siloed in their thinking, and to provide leadership.

“Currently on Voyager, what that looks like is making some tough calls,” said Rankin. “These are aging spacecraft, and we want to keep the mission running as long as possible. But they’re in completely new territory, both geographically and in the sense that these are the first spacecraft that have been operating for this long. They just celebrated their 45th launch anniversaries. So how they age, and how long can they keep going — that is all critical to prioritize the science that is left.”

The Voyagers are powered by plutonium-238, which has a half-life of 88 years. “That seemed like forever when they launched, but now we’re more than halfway through that half-life, and there’s not much base power to operate the spacecraft,” Rankin said. “The Voyager teams already shut down some of the instruments — they turned off the cameras with the end of the planetary mission — and I saw Ed lead the Voyager team to a consensus decision to start turning off the heaters to the remaining instruments. Nobody knew if the instruments could operate without the heaters, but the choice was either turn off more instruments, turn off the heaters, or lose the spacecraft. What do you do?”

Fortunately, the instruments have continued to generate and transmit data as the heaters have been shut down, one by one.

The aging spacecraft also have nowhere near the transmission power needed to send a clear signal across the billions of miles back to Earth, which means that Earth-based telescopes have had to work harder and harder to detect their faint signals.

“Ed once described it to me as a blinking refrigerator light bulb in space,” said Rankin. “That’s the kind of signal strength we’re talking about. So we have to have heroic efforts on the ground to communicate with them. If the advancements on Earth hadn’t happened — including building 70-meter dishes for the Deep Space Network — we wouldn’t have been able to keep communicating with the Voyagers as they got further and further away.”

Voyager’s continuing mission, to boldly go where no spacecraft has gone before — and look back

Voyager 1 is now billions of miles outside the heliopause, as far from that boundary as Neptune is from Earth, and speeding onward at about a million miles a day.

And it’s still making remarkable discoveries, said Rankin. “Even at that distance, it still sees effects from the sun. When solar flares or coronal mass ejections erupt from the sun, they travel through the solar system, and it turns out they can pile up and merge into giant events that actually reach all the way to the heliopause and then shove against that boundary — and then that sends ripples into interstellar space. And Voyager can see it.”

The Voyagers’ distance also gives them a completely different perspective on Earth and the sun. “Voyager allows us, for the first time, to look at our own star and our own planetary system from the outside,” Rankin said. “For decades, we’ve looked at other stars from the outside, and gathered remote data, but all that we knew about our own star was ‘from the inside,’ so to speak. So, what do we look like from the outside? The only way to know is to have a spacecraft out there — or, better yet, two spacecraft at different locations.”

by Liz Fuller-Wright, first published @ Princeton


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Collaboration of the Cited

Collaboration of the Cited

The cover of Philosophical Transactions, 1665.

Philosophical Transactions, 1665.

Biology’s ‘highly cited’ researchers collaborate in forest science.

The first scientific journal, still in print, was launched in 1665 by the Royal Society in London, but peer review and the ubiquitous citations we’ve come to expect in research documents are a relatively recent innovation. According to the Broad Institute, it began as late as the mid-1970s.

To distinguish high-level “influencers” in research, Clarivate, a company that provides insights and analytics to accelerate the pace of innovation, annually announces the most “highly cited” researchers. This year, three of those are located at the University of Utah, and all of them are based in the College of Science: Peter Stang (chemistry), John Sperry (biology) and William “Bill” Anderegg (biology).

Sperry and Anderegg have worked closely together, publishing multiple papers over the course of about six years in the areas of plant hydrology and forest stress. Their research is an auspicious example of how, in the tradition of peer-reviewed research, scientists routinely stand on the shoulders of others to move forward human understanding of life sciences. This is, of course, especially critical during an era when global warming demands that we have innovative solutions now.

Vascular health and function

When Sperry started working on plant hydro-vascular systems and their failure by cavitation more than forty years ago, he was one of only a small handful of people who knew it was an important topic. “Scientifically, the field was a goldmine,” said Sperry, “wide open with no competition. Once I’d developed a simple method for measuring cavitation in plant xylem as a grad student, I was off to the races.”

Sperry’s acknowledgment as a highly cited researcher would suggest he ran that race well before retiring in 2019. “I’ve always been thankful to Utah biology for going out on a limb with my hire,” he reports. “Once at Utah, the discoveries about cavitation and its consequences for plant ecology and evolution steadily drew more attention and the field grew.”


Sperry holding a custom rotor.

“Once at Utah, the discoveries about cavitation and its consequences for plant ecology and evolution steadily drew more attention and the field grew.”


New method developments by his lab helped acquire larger data sets on how plant form and function have evolved. Sperry custom designed centrifuge rotors to quickly expose the vascular system of plants to a known negative pressure. This in turn allowed him to create the kinds of vulnerability curves, which improve prediction of plant water use and to help move his research toward macro applications in forests to predict plant responses to climate change.

Demonstrating the linkage between the physics of water transport and the physiological regulation of plant gas exchange and photosynthesis via stomata was key to better understanding how plants respond to environmental change. This is because transport physics is easier to measure and model than the physiology underlying stomatal behavior. “I always knew that vascular health and function had to be at least as important to plants as it is to animals, and so it has proven to be.”

Scaling up through computation

While necessity is the mother of invention—as in Sperry’s early centrifuge–computational power, one could argue, is the mother of scaling up research impacts. As a post-doctoral researcher in the lab of Mel Tyree at the University of Vermont, Sperry learned early on the utility of blending theoretical modeling with empirical work. “Decades of weather parameters can [now] be converted into continuous half-hourly predictions of photosynthesis, transpiration, xylem pressures and so forth in a matter of hours,” he explains of how big data revolutionized his work. “In my case, modeling converts the measured cavitation response. . .. This paved the way for improved predictions of responses to climate change. The utility of this approach has gradually become appreciated . . . hence the number of citations.”

It is no coincidence that Sperry and Anderegg who both share a research interest in plant hydraulics are cited frequently. But while Sperry’s work focused on physiological fundamentals, Anderegg’s ongoing forest research is more wide-ranging and focuses on ecological consequences at often large scales. Said Sperry of his colleague, “his measurements helped explain the drought-induced mortality he had observed in the field. … What Bill has done, in spades, is to realize the potential of plant hydraulics for improving large-scale (landscape to globe) understanding of forest health.”

He continues to watch with interest Anderegg’s research which he said, “stimulated the leap from vascular physiology at the whole-plant scale to the forest as a whole and into a future of climate change. He played a key role in identifying how to model the trade-off between transpiration and photosynthesis, which was crucial for bridging the gap between vascular health and photosynthetic health.”

For Anderegg, who first met Sperry when he was a graduate student studying cavitation in Colorado aspens, the feeling of admiration is mutual. While attending a major conference in the field, Anderegg remembers an artistic set of wooden branches—a “mentor tree.” There, “young scientists anonymously wrote the name of someone who had changed their career. John’s name was all over the tree and was the most frequent name by far.”

Sperry would agree with Anderegg when the latter explains how “climate change is already having major impacts on our landscapes, forests, and communities, and thus scientific research to help us understand, mitigate, and adapt to climate change is growing rapidly.” As director of the new Wilkes Center for Climate Science and Policy housed in the College of Science, Anderegg is at the forefront of trying to understand more fully the western United States’ forest environments calling it “a global hotspot for climate impacts.” His aim both within the Wilkes Center and without is “to make our research in this region useful, timely, and relevant.”

“John’s work in the field of plant water transport was seminal and at the vanguard of the field,” said Anderegg, “So it’s not a surprise at all to me that it continues to be widely cited even after his retirement.”

The defining issues of our age

At the helm of the Wilkes Center, Anderegg is keen to collaborate with stakeholders and multiple partners to analyze and innovate on climate solutions. The Center’s intention is to inform policy in key areas of water resources, climate extremes, and nature-based climate solutions. Funded by a $20 million gift from Clay and Marie Wilkes, the Center illuminates climate impacts on local communities, economies, ecosystems, and human health in Utah and around the globe while developing key tools to mitigate, adapt, and manage climate impacts.

The directorship is a natural one for Anderegg whose principal query is driven by concerns that drought, insects, and wildfire may devastate forests in the coming decades. “We study how drought and climate change affect forest ecosystems, including tree physiology, species interactions, carbon cycling and biosphere-atmosphere feedback,” he writes. “This research spans a broad array of spatial scales from xylem cells to ecosystems and seeks to gain a better mechanistic understanding of how climate change will affect forests around the world.”


William “Bill” Anderegg

“We study how drought and climate change affect forest ecosystems, including tree physiology, species interactions, carbon cycling and biosphere-atmosphere feedback”


A recent paper of his in Science presents a climate risk analysis of the Earth’s forests in the 21 century. Before that publication, his team not only determined that more people are suffering from pollen-related allergies and that people who do have these allergies are suffering longer pollen seasons than they used to but that the causes, while wide-ranging, are mainly because of climate change. The Wilkes Center aims to scale up such societally relevant research, provide tools for stakeholders to make decisions and leverage science and education to inform public policy.

Accumulating citations in scientific, peer-reviewed journals leading to warm accolades of being one of an elite group of the “highly-cited” is not just about giving credit where credit is due. Instead, citations are signs of momentum, the importance of a given field of study, and robust collaboration. They are mechanisms for the leveraging of data and interpretation of that data. And, like the exhilarating high-volume transport upwards of water through xylem in trillions of trees across the earth, citations help link together the scientific literature and let scientists stand on the shoulders of giants to tackle society’s greatest challenges.


by David Pace, first published in the School of Biological Sciences

Pauling Medal

Dr. Cynthia J. Burrows

Dr. Cynthia Burrows

Distinguished Professor Dr. Cynthia Burrows is the 2022 Pauling Medal awardee.

Cynthia J. Burrows, Distinguished Professor in the Department of Chemistry at the University of Utah, where she is also the Thatcher Presidential Endowed Chair of Biological Chemistry. Burrows was the Senior Editor of the Journal of Organic Chemistry (2001-2013) and became Editor-in-Chief of Accounts of Chemical Research in 2014.

Burrows acquired a B.A. degree in Chemistry at the University of Colorado (1975). There she worked on Stern-Volmer plots in Stanley Cristol's laboratory during her senior year. She continued to study physical organic chemistry at Cornell University, where she received a Ph.D. degree in Chemistry in 1982 working in Barry Carpenter's laboratory. Her Ph.D. thesis work focused on cyano-substituted allyl vinyl ethers. Burrows then conducted a short post-doctoral research stint with Jean-Marie Lehn in Strasbourg, France.

The Pauling Medal recognizes chemists who have made outstanding national and international contributions to the field. It was named for Dr. Linus Pauling and is presented by the Puget Sound and Portland sections of the American Chemical Society. Dr. Burrows was awarded her medal October 29th, 2022 in Portland, Oregon, with speeches by Valeria Molinero, Alison Butler, and Jonathon Sessler.

The Burrows laboratory is interested in nucleic acid chemistry, DNA sequencing technology, and DNA damage. Her research team (consisting of organic, biological, analytical and inorganic chemists) focuses on chemical processes that result in the formation of mutations, which could lead to diseases (such as cancer). Her work includes studying site-specifically modified DNA and RNA strands and DNA-protein cross linking. Burrows and her group are widely known for expanding the studies on nanopore technology by developing a method for detecting DNA damage using a nanopore.

One of the objectives of the Burrows Laboratory is to apply nanopore technology to identify, quantify, and analyze DNA damage brought on by oxidative stresses. Burrows focuses on the damage found in human telomeric sequences, crucial chromosomal regions that provide protection from degradation and are subject to problems during DNA replication. Additionally, Burrows’ research in altering nucleic acid composition can provide valuable information in genetic diseases as well as manipulating the function of DNA and RNA in cells.

Awards and honors include:

  • NSF - CNRS Exchange of Scientists Fellowship, 1981–82
  • Japan Soc. for the Promotion of Science Research Fellow, 1989–90
  • NSF Creativity Award, 1993–95
  • NSF Career Advancement Award, 1993–94
  • Bioorganic & Natural Products Study Section, NIH, 1990–94
  • NSF Math & Physical Sciences Advisory Committee, 2005–08
  • Assoc. Editor, Organic Letters, 1999–2002
  • Senior Editor, Journal of Organic Chemistry, 2001–13
  • Robert W. Parry Teaching Award, 2002
  • ACS Utah Award, 2000
  • Bea Singer Award, 2004
  • Fellow, AAAS, 2004
  • Distinguished Scholarly and Creative Research Award, Univ. of Utah, 2005
  • Cope Scholar Award, American Chemical Society, 2008
  • Director, USTAR Governing Authority, 2009-2017
  • Member, American Academy of Arts and Sciences, 2009
  • ACS Fellow, 2010
  • Distinguished Teaching Award, 2011
  • Editor-in-Chief, Accounts of Chemical Research, 2014
  • Linda K. Amos Award for Distinguished Service to Women of U of U, 2014
  • Member, National Academy of Science, 2014
  • ACS James Flack Norris Award in Physical Organic Chemistry, 2018
  • Willard Gibbs Award, 2018


first published @ chem.utah.edu

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Art & Air Quality

Art & Air Quality

Wendy Wischer

Public art piece finds common ground in the fight for air quality.

UTA Trax cars zip from University hills to west-side valleys, past schools, shops and churches. Carrying more than just passengers, these cars hold research-grade air quality sensors. They catalog things we can’t see—ozone, the valley’s main summertime polluter, and PM 2.5, the particulate matter that blankets our wintertime, turning Salt Lake City into a snow globe of ash. Soon they’ll carry something else: segments of public art piece In Search of Blue Sky, decorating  Trax car interiors and the sides of public buses. The installation seeks both to raise community awareness of the air quality data and embed it with personal meaning. “Just putting data out there doesn’t move people, doesn’t change people,” says Wendy Wischer, the project’s artist. “Artwork can pull at emotions, and to act, we need to be moved emotionally.”

Wischer was first approached by John Lin several years ago when the sensors were installed. Both faculty at the University of Utah, Wischer teaches Sculpture Intermedia in the College of Fine Arts and Lin is a professor of Atmospheric Sciences. They received funding through the university’s Global Change & Sustainability Center (GCSC), described on its website as “an interdisciplinary hub catalyzing research on global [climate] change and sustainability.” Creative Writing Ph.D. candidate Lindsey Webb from the College of Humanities became their student collaborator, who collaborated with Wischer and Lin to write the text.

John Lin

“The more we care about each other [and] the more we feel connected to each other, the more we’re going to take action that supports a healthier environment for everybody.”

Wischer boasts a long resume of environmental art installations, having collaborated with geologists and engineers in the past. Her work explores boundaries and the places where art and science collide. Art brings a different perspective and problem-solving process to climate issues, one Wischer believes may help us navigate their complexity. “I often am seeking connecting threads between disparate ideas,” she says. “We need the disciplinary expertise, but we also need to think about … incorporating those skill sets in different ways.”

The In Search of Blue Sky panels will be a pop of color in the cityscape, each one boasting a short poem or phrase on a serene, blue-sky backdrop. Wispy cirrus clouds seen in fair weather drift lazily from one panel to the next. Webb’s words are simple, yet poetic meditations on the air around us, its beauty and degradation. In Search of Blue Sky’s simplicity may be its strongest asset—in the chaos of traffic, billboards and advertisements, it’s a breath of fresh air. It evokes a longing for that simplicity, just out of memory.

A QR code or URL lets passersby with a smartphone instantly access both the project’s website and the data collected in real-time by the Wasatch Environmental Observatory (WEO), perhaps even captured by the train car they’re sitting in. Wischer says, “I hope that this curiosity sparks conversations and that people will take further action, whether that’s riding more public transportation … [or] voting in ways that support certain policies and programs.” The data is meant for everyone. But, says Wischer, most people don’t know it exists. The campaign is accessible and bilingual (both the signage and website are in English and Spanish), and she hopes it will inspire people to learn and care more about the issue, inciting action in whatever form that might take.

Interior signage for buses and trains.

Air quality has been a pressing issue in Salt Lake City for a long time, though little has been done on the state and city levels to address it. One notable takeaway from the data is the inequitable distribution of hazardous air quality. Although everyone is affected, communities on the west side and lower-income areas suffer the most as the negative health effects of air pollution compound with other structural inequalities. As in all climate fights, our greatest weapon comes in community; our strongest allies are each other. Wischer wants the art of In Search of Blue Sky to remind us that we all have a stake in the fight. “The more we care about each other [and] the more we feel connected to each other, the more we’re going to take action that supports a healthier environment for everybody,” she says

“I often am seeking connecting threads between disparate ideas.”

Wischer believes that the biggest victories in the climate fight often come from local, grassroots efforts. “There are a number of different solutions that might be available,” she says, “but we can’t even get there if we don’t have conversations. We have to have common ground to understand why this is important and why we should care about a neighborhood that’s affected differently than our own.” One solution is public transportation, the vessel for In Search of Blue Sky. Wischer notes that the messages inside the Trax cars are different from those outside—they’re messages of thanks. “We’re always saying ‘oh, you should do this, you should do that.’ Rarely do we say ‘thank you’ for actually doing it,” says Wischer.

Our air is precious. When it’s abundant, we hardly notice it. After three short minutes without it, we die. In Search of Blue Sky reminds us what we’re fighting for; it reminds us that we’re all in this together.

Utah Transit Authority Bus Advertising

In Search of Blue Sky will run on UTA buses and Trax cars through the month of January, when Salt Lake’s winter inversion is at its worst. To learn more about the project, visit ecoart.website.

By . Originally published @SLUG Magazine, photos by .


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