Remembering Uwe Fink

Scientific Life of Professor Emeritus Uwe Fink

Professor Emeritus Uwe Fink passed away on 18 January 2026 after a brief illness. Fink was born in Germany in 1939, spending his early childhood under difficult circumstances during the Third Reich. At the end of World War II, his family found themselves in Göppingen in the American Zone of Occupation. From there, they emigrated to Canada, where Fink attended high school, and later they moved to Portland, Maine in the USA. Fink graduated with a BS in Engineering Physics from the University of Maine in 1961. He was then admitted to graduate studies at Pennsylvania State University, where he earned an MS in Physics in 1963 and a PhD in Physics in 1965, completing a dissertation on “The quadrupole spectrum of molecular hydrogen" under the supervision of Professor David H. Rank, a distinguished physicist who pioneered modern infrared spectroscopy and was a leader in adapting lasers for spectroscopic techniques and in optical instrument design.

Fink's initial postdoctoral position was back in Europe, performing balloon-borne atmospheric measurements for the recently-established Institute for Atmospheric Science (Brussels, Belgium) at the remote location of Aire-sur-l’Adour, France. After concluding this postdoc, Fink returned to the USA seeking another position, applying to companies such as Bell Laboratories and Corning. Learning from his good friend and former fellow Penn State physics graduate student William Bickel that there was an opening in the Physics Department at the University of Arizona in the beam-foil spectroscopy laboratory of Professor Stanley Bashkin, Fink applied and was accepted, beginning employment at UA in 1967. At the time, the seven-year-old LPL under the directorship of Gerard Kuiper was in the process of moving into its new building, leaving the small area it had shared with Physics in the PAS building. Recognizing Fink's talents and their applicability to his research on planetary atmospheres, Kuiper invited Fink to join LPL in 1968. From that date until his death 58 years later, Fink was a stalwart member of LPL. He was a founding member of LPL's academic arm, the Department of Planetary Sciences (chartered in 1972).

During his long career, Fink carried out laboratory spectroscopy and observations on all of the planets in the solar system and their satellites as well as asteroids and comets. During this golden age of planetary exploration, he developed and built instruments for laboratory use and telescopic observations using the technique of Fourier spectroscopy and later CCD spectroscopy. The laboratory work identified the opacity spectra of molecules that could then be searched for spectroscopically. He was the first to employ CCD’s for planetary spectroscopy, enabling him to obtain the first good visible and near IR spectrum of Pluto. Highlights include the discovery of the icy composition of Saturn’s rings, measurements of ices on the Galilean satellites, and an early measurement of water vapor in the atmosphere of Venus from airborne spectra. A major advance was the first detection (in collaboration with Harold Larson) of water vapor in the atmosphere of Jupiter, particularly relevant today in the context of measurements of the atmospheric compositions of extrasolar giant planets. Also important was their first detection of the disequilibrium species GeH4 (germane, the germanium analog of methane) and PH3 (phosphine) in the atmosphere of Jupiter. His spectra of Jupiter and molecular detections are still oft cited in the modern brown dwarf and extrasolar giant planet literature.

For 1993-1994, Fink was awarded a Humboldt Prize to work at the German Aerospace Center (Deutsches Zentrum für Luft- und Raumfahrt; DLR) in Berlin.

During the period 1985-2005, Fink carried out extensive observations of comets, their chemical composition, production rates and taxonomy, resulting in a summary paper of the spectroscopic taxonomy of 92 comets. For more than 10 years after his official retirement, Fink was a Co-Investigator on the ESA-NASA Rosetta mission to comet 67P.

Fink’s contributions to science (with over 110 published papers) and the life of LPL will be long remembered.

— Bill Hubbard and Mark Marley

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What can I say about Uwe Fink? A lot, actually. It all begins with mourning and knowing I won’t get to hear new stories about his tractor or his efforts to reforest the world, starting with a corner of Oregon. Thinking of that tractor always puts a smile on my face. I was delighted to see Uwe at the 2013 DPS Meeting in Denver, where he was showing off pictures with him sitting on his shiny new green tractor. The grin he showed in person and in the photographs told the whole story. There may or may not be any connection with that and my getting a tractor of my own some years later.

Our lives overlapped for 5 short years, from 1980 to 1985, when I was a graduate student and Uwe was my advisor. He picked me, and I said yes without us having met first. I’m sure that our shared physics and laboratory background was an important factor in the choice. It surely gave us common ground at the start. Though our time working together was short, he had a profound influence on my development as a scientist and set me up for what became a very fulfilling career.

One of the shorter chapters in Uwe’s research career was his work on Pluto. Following close on the heels of Dale Cruikshank’s filter photometry detection of methane, Uwe was the first to show us an actual spectrum of Pluto’s surface. Those results were the spark that ignited my lifelong passion for learning more about this distant world, culminating in a NASA mission.

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That first spectrum of Pluto is a saga in its own right. At its core, this result shows Uwe at his best as a persistent and opportunistic schemer, in a good way. Digital imaging devices (CCDs) were just coming on the scene, and Uwe pounced on the notion of applying that to spectroscopy. It was my good fortune to be a part of that development in the early days. Uwe’s schemes opened so many interesting doors for me, particularly with instrumentation design, construction, implementation, and use. He was an incredible facilitator, bringing together some of the most profoundly creative and competent people I have ever worked with. Every one of

 these exceptional people (including Uwe) was gracious enough to share their knowledge with me along the way. In the years since, I’ve learned just how rare that working environment can be and only deepened my appreciation of Uwe.

Learning with Uwe took on many forms, going well beyond expected formal education goals. I’m edging closer to 200 publications, and with every one, Uwe’s voice is ever present in my head guiding me forward. The most frequently used bit of advice is to always describe each figure and point out what I see in it for the edification of the reader. Never leave the figure to speak for itself. The most important lesson he provided was when I was writing my dissertation. It became abundantly clear that I was ill-prepared as a writer. His willingness to help with copyediting without judgment kept me on track and cemented a resolve to learn how to write on my own.

My personal collection of pictures from that bygone era are few and far between. Here is one of the few showing Uwe’s team hard at work at the 61-in telescope with his spectrograph and the WFPC traveling camera (I’m on the ladder). I have many fond memories from that observatory, but this picture is emblematic of how he would leave us alone to get the job done. He was always around but guiding only as much as the situation required. Thanks for everything, Uwe!

— Marc Buie, 2026 Feb 6