The Rochester professor emeritus and new American Astronomical Society fellow now explores the brainās waste disposal system.
John (āJackā) Thomas officially retired in 2014, but the honors keep coming.
The professor emeritus of astronomy at the was recently of the (AAS). The society, which has existed since 1899, began recognizing fellows three years ago. The AAS is honoring Thomas not only for his service and leadership, but also for five decades of groundbreaking contributions to solar and stellar physics, āincluding advancements in our understanding of the behavior of magnetic fields and theoretical and observational studies of sunspots.ā
Not content to rest on his laurels, Thomas, now 80, has started a new chapter in his illustrious career. Lured from retirement, he is pursuing an altogether different but equally groundbreaking area of research.
Thomas, who is also professor emeritus of mechanical and aerospace sciences, is helping , professor of neurology and neurosurgery at the Universityās Medical Center, expand on her breakthrough discoveries about the brainās glymphatic system. The system, which comprises a plumbing network that piggybacks on the brainās blood vessels and pumps cerebral spinal fluid (CSF) through the brainās tissue, flushes away waste.
The collaboration also involves two of Thomasās colleagues in the , associate professor Doug Kelley and assistant professor Jessica Shang.
āThis whole thing has been absolutely amazing,ā says Thomas. āI have been reborn as a neuroscientist. I am learning so many things about biology that I never knew about. Itās just been wonderful.ā
Ever-expanding collaborations yielded solar discoveries
Thomas was interested in astronomy as a child, looking at stars and planets through a small telescope with his father.
However, his interest in astrophysics was sparked during his doctoral work on magnetohydrodynamic turbulence at Purdue University and a subsequent NATO postdoctoral fellowship at the University of Cambridge from 1966 to 1967.
After joining what was then called the Department of Mechanical and Aerospace Sciences at Rochester, Thomas began collaborating on theoretical modeling of fluid flows on the sun with Alfred Clark, professor of mechanical engineering, of mathematics, and, later, of biomedical engineering.
Over the years, Thomasās collaborations expanded to include colleagues in the at Rochester, including Hugh Van Horn, Adam Frank, and Eric Blackman. He also worked with researchers at the National Solar Observatory in New Mexico, the High Altitude Observatory in Boulder, Colorado, and the Laboratory for Space Astrophysics and Fundamental Physics in Madrid, among other institutions.
Thomasās main research focus was the sunās magnetic field and how it gives rise to sunspots on the sunās surface. He modeled the structure and dynamics of sunspots, including the motion of waves across them and the flow of material inside. In the early 1980s, Thomas originated the concept of probing beneath sunspots by observing acoustic oscillationsāessentially āsunspot seismologyāāto gain previously unknown information about the sunspotsā structure.
āIām very proud of the work I did with my colleague Nigel Weiss (University of Cambridge),ā Thomas says. āHe and I wrote a book together for Cambridge Press called , published in 2008. A lot of the work we did is described there.ā Thomas spent sabbatical years at Cambridge and Oxford in England, and he is a life member of Clare Hall, Cambridge, and Worcester College, Oxford.
In 1993, Thomas received a Guggenheim Fellowship for his research on solar and stellar magnetic fields.
He was elected a fellow of the American Physical Society in 2000 for āmajor contributions to solar magnetohydrodynamics.ā And in 2007, Thomas was named a fellow of the American Association for the Advancement of Science for elucidating the physics of the sun and other stars, and for his broader contributions to the solar community. Most notably, Thomas served for 10 years as scientific editor of The Astrophysical Journal, the foremost journal in the field. He also chaired the Solar Physics Division of the American Astronomical Society from 1995 to 1997.
At Rochester, Thomas served as an associate dean for graduate studies in the College of Engineering and Applied Sciences (now the Hajim School of Engineering & Applied Sciences) and then as the University Dean of Graduate Studies for eight years.
All of this would be more than enough to constitute a remarkable career.
But then in late 2016ātwo years after he retiredāThomas received an email from Maiken Nedergaard.
Cancer diagnosis spurs return to research
A rapid series of discoveries from Nedergaardās lab four years earlier showed that the brain has its own unique waste removal system. Moreover, this glymphatic system is primarily active while we sleep. The latter discovery was selected by Science magazine as one of 2015ās .
Nedergaard asked Thomas to help her research group better understand the microfluidics involved in this glymphatic cleansing system. He agreed, and immediately contacted his colleague, Douglas Kelley, whose research group had already developed algorithms to track particle flows in fluids. The algorithms could be readily applied to Nedergaardās study.
Thomas says there were two motivations for him to come out of retirement.
āThe fluid dynamics interested me,ā he says. Yet there was a strong personal motivation as well: his wife had been diagnosed with glioblastoma, an aggressive cancer that they both knew to be incurable. The glymphatic system offers possible pathways for getting drugs to the brain, and perhaps eventually providing better treatment for future patients with glioblastoma and other brain diseases, Thomas says.
āMy wife was very pleased to see me possibly getting back into research, that I would have this to keep me busy in retirement,ā Thomas says. āAnd she was right on the mark. It was really a big help in dealing with her loss.ā
Since the collaboration with Nedergaard started in early 2017, Thomas has worked with Kelley on seven published papers and two more currently under review, and with Nedergaard on several other published papers. He has also published a single-author paper on brain fluids and recently submitted another.
In retrospect, Thomas is surprised that Nedergaard contacted him, ābecause I had done things on this huge astrophysical scale, at kind of the opposite extreme of the work she is doing.ā
Kelley is glad that she did.
Thomas is āhighly productive and tremendously generous with his time,ā Kelley says. āHe attends biweekly meetings with our research teams. His insights are a tremendous help to students, postdocs, and faculty alike. With so much experience, his instincts for solving scientific puzzles and interpersonal challenges are just excellent. Itās an honor to have him as a mentor and colleague.
āJack is unarguably a leader in the field.ā
The perks of academia: āopportunities to just keep learningā
Thomas says his career has been a testament to the unique opportunities that academia offers to pursue āa lifetime of learning.ā
Many of the courses he taught fell outside his primary research area, requiring him to continually refresh and update his knowledge of basic subjects, such as fluid dynamics, plasma physics, and thermodynamics. āThereās a joke among professors that if you want to learn a subject, volunteer to teach it, because then youāre forced to learn it. But to me that was just a delight,ā Thomas says.
Thomasās own undergraduate degree at Purdue was in engineering sciences.
āSo, basically I was an applied mathematician,ā he says. āBut then I started doing astrophysics. I had to learn about that field, and then geophysics. I later did some research on lake circulation in Lake Ontario, some oceanography, worked on convection in the earthās mantle, and then broader aspects of solar and stellar physics. And now Iām learning brain anatomy, and all sorts of things,ā Thomas says.
āThatās what comes with the academic life. There are always opportunities to just keep learning.ā
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