2004 Barringer Medal for Peter Schultz

While researching Pete's background for this citation, I soon became aware of what little I knew of the entirety of his tremendous contributions to impact cratering. I called out for help from my colleagues and his colleagues, his former students, and his current students. The response, needless to say, was overwhelming. Everyone has an opinion about Pete … and they are mostly good. I think of Pete as an observer, an experimenter, and a teacher. He has many positive attributes and a few faults (I won't go into those here). Most significantly, Pete is creative. Many of his ideas have proven to be right (Pete is without doubt the world's expert on oblique impacts); some of his ideas are still vigorously debated (e.g., the role of the atmosphere in ejecta emplacement); however, without exception, every one of his creative ideas is supported by images, field observations, and experiments. Pete has tremendous energy and enthusiasm. This is particularly true of his teaching. How did he get this way? It is often said that, to find answers, one looks in the past … so let's look at Pete's career. Peter Schultz received his Bachelor's degree in Astronomy from Carleton College in 1966 and his PhD in Astronomy from the University of Texas at Austin in 1972. A book based on his dissertation, published in 1976 with the title “Moon Morphology” is a classic that can still be found on the bookshelves of planetary scientists today. In this book, Pete demonstrates his keen talents as an observer and his ability to relate those observations to the impact process. He applies these observational talents to everything he does: experiments, terrestrial crater field work, and assessment of impact craters and the cratering process on other planets. His keen observational talents also go hand-in-hand with his other great passion: all things photographic. Anyone that has had the honor of visiting Pete and Barb's house has seen their museum quality collection of antique cameras and photographs. Soon after receiving his PhD, Pete became a research associate at NASA Ames where he worked with Don Gault (another Barringer Medal winner) on seismic modification of surface features antipodal to large impacts and how seismic shaking from impacts could soften planetary features and alter their apparent age. This work with Don was just the beginning of a long and prosperous 20-year scientific collaboration. Together, Pete and Don co-authored at least nine peer-reviewed papers and over 30 abstracts. Pete's paper (with Don as second author) on “Atmospheric Effects on Martian Ejecta Emplacement,” published in 1979, is a seminal work that is often cited. It is rare that detailed analysis, experiments, and photo-geologic observation appear together in such a balanced form. In his memorium to Gault that Pete wrote in 1999, he says “Through [Don's] experiments, impact cratering stopped looking like water fountains or nuclear explosions.” Beginning with this paper in 1979 and continuing to the present, I think that Pete has changed our picture of the crater–atmosphere interaction in a similar way. No longer a picture of a random, jumbled mixture of ejecta particles, the ejecta curtain's interaction with the atmosphere is organized, turbulent perhaps, but categorized into distinct regimes dependent on particle size, crater size, and atmospheric density. He has shown that the atmosphere affects ejecta emplacement, cratering efficiency, and crater growth. From 1976 to 1984, Pete was at the Lunar and Planetary Institute where he worked on secondary crater processes, mapping swirls on the Moon that he attributed to cometary impact and computer simulations of impacts. During this time, he published a paper on clustered impacts that one of my colleagues labeled as “sterling.” But it is in 1979 and 1980 that one of the more notorious chapters of Pete's professional career occurs. It gives us a clue of Pete's creativity. In one of his Lunar and Planetary Science abstracts published in 1980 entitled “Multiple-Body Impacts: Implications for Secondary Impact Processes”, Pete describes his results this way: “Projectiles with different viscosities were used to observe the transition from strong bodies to weakly bonded and multiple-body systems. Thinly crusted projectiles containing albumen produced very shallow craters with ratios greater than 20:1 as noted in (reference 6). Moreover, the resulting craters exhibited a pronounced central mound with the projectile lining the crater floor and wall. A similar but less pronounced effect was observed for higher viscosity albumen.” Pete had found a particularly simple and elegant way to study the role of projectile viscosity in crater development … using eggs! By varying the degree of cooking, he could change the viscosity of egg white (albumen) from the low viscosity raw form to the high viscosity hard-boiled form without changing projectile mass, density or bulk composition. Somehow, even after the egg-impact escapade, Pete, in 1984, became a faculty member at Brown University. He has not done much since then, unless you include his work on impact vaporization; the role of impact angle; projectile shape effects on depth, diameter, and cratering efficiency; impact cratering on Mercury; “Prolonged Global Catastrophes from Oblique Impacts”; atmospheric effects on Venus; his role in the discovery of impact events at Rio Cuarto and other locations in Argentina; and now his role in the ultimate impact experiment: Deep Impact. Pete has unquestionably changed our picture of oblique impacts through his experiments, field observations, and photo-geologic interpretations. Indeed, the oblique impact theme permeates almost everything he does. Time and time again, he has shown the error of thinking vertically. Pete has received many awards including a certificate of special recognition from the United States House of Representatives, a certificate of appreciation from the Rhode Island House of Representatives, two best paper awards from the Hypervelocity Impact Society and a medal of achievement from the National Academy of Sciences in Argentina. He is the science coordinator for the NASA-Ames Vertical Gun and a member of countless advisory committees, review panels, and organizing committees. He is director of the Northeast Planetary Data Center located at Brown University and director of NASA/Brown University Space Grant that enriches the education of about 6000 grade school children in Rhode Island every year. In short, Pete gives back to his profession and community every chance he gets. In closing, I think it is far too rare an occurrence that a student gets to thank his teacher in a public setting such as this. On behalf of myself and many others, Pete … thank you … Mr. President, I am pleased to present Peter Schultz for the Barringer Medal. The citation used published information. No data was generated for this work.