The Greeley Early Career Award is named for pioneering planetary scientist Ronald Greeley. Ron was involved in nearly every major planetary mission from the 1970s until his death and was extraordinarily active in service to the planetary science community. Ron’s greatest legacies, however, are those he mentored through the decades, and it is young scientists whose work and promise we seek to recognize. This year’s Greeley Award winner is Brandon Johnson, an assistant professor at Brown University.
Brandon received his Ph.D. in physics from Purdue University in 2013 for fundamental work on the mechanisms by which impact spherules and melt droplets form in large cratering events. His work linked the size of ancient spherules to the size and velocity of the projectile that created them. He demonstrated that the impactor flux was much higher in the Archean than it is today.
Although his core area of expertise is impact cratering, Brandon has addressed a range of fundamental problems in planetary science. He revived the controversial idea of an impact origin of chondrules by developing models for impact jetting onto the surfaces of protoplanets. As the jetting model was debated among meteoriticists, Brandon linked CB chondrules to the high-energy impacts generated by Jupiter’s growth and migration. This work highlights Brandon’s talent in combining collision physics with planetary observations in the broader context of planet formation.
Brandon has also provided new insight into the physical properties of the Sputnik Planitia basin on Pluto. He showed that the positive gravity anomaly required the presence of a subsurface ocean, placing a key thermal constraint on the history of Pluto. With important contributions spanning the mechanics of impact basin formation to tectonics on icy satellites, Brandon’s work has consistently reframed our views on important planetary processes.
AGU congratulates Brandon Johnson for his diverse and creative contributions to planetary science.
—Sarah T. Stewart, University of California, Davis
I am honored to be named the 2018 recipient of the Ronald Greeley Early Career Award in Planetary Sciences. This award is truly a source of encouragement and validation for the research that I love. I thank those who nominated me for this honor, Sarah Stewart for writing the citation, and the award committee for this recognition.
I would like to acknowledge all the people who have supported me throughout the formative years of my career. I am especially indebted to my Ph.D. advisor, Jay Melosh, for his continuous support. Just 8 years ago I was working in a condensed matter physics lab, unhappy, contemplating leaving graduate school, and looking for other opportunities. After a serendipitous meeting, Jay introduced me to the study of impact cratering and kindled my passion for planetary science. In addition, I thank my amazing postdoctoral advisor, Maria Zuber, who sparked my enthusiasm by encouraging me to pursue the research that I was most excited about; my undergraduate advisor, Ranjit Pati, for having confidence in my potential and encouraging me to apply to graduate school; and the many unofficial advisors who have generously offered their expertise and guidance along the way. I am also grateful to all of my colleagues and collaborators who have shared and continue to share in the excitement of discovery with me.
Last, but certainly not least, I thank Alexandria, my wife and fellow scientist. I owe any success I have to Alexandria and her unwavering support.
—Brandon C. Johnson, Brown University, Providence, R.I.