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Planetary Science

The Moon


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Ali Bramson

Ali Bramson, Assistant Professor

Ali Bramson's website

Ali earned her BS degrees in astrophysics and physics, with a minor in computer science, from the University of Wisconsin-Madison in 2011. She then moved to the University of Arizona's Lunar and Planetary Laboratory (LPL) for her PhD in planetary sciences, with a minor in geosciences, which she received in 2018. After her PhD she stayed at LPL for a postdoc in planetary radar before joining Purdue EAPS in 2020. Ali studies problems related to understanding the quantitative geomorphology of other planets, especially the physical processes related to ice and volatiles that affect the surfaces of solid bodies in our solar system. She tackles these problems using a combination of spacecraft remote sensing observations (especially radar) and theoretical modeling, supplemented by occasional field work at terrestrial analog sites and experimental studies. Her research on Martian mid-latitude ice is helping to shape the future of in situ resource utilization and human exploration of Mars.


Andy Freed

Andy Freed, Professor

Andy Freed's website

Andy received his PhD from the U. of Arizona in 1998, and after postdoc stints at UC Berkeley and The Carnegie Institution of Washington, joined EAPS in 2003. Andy’s research utilizes numerical modeling to understand a variety of time-dependent geodynamical processes that involve viscous flow and conductive cooling, including terrestrial projects dealing with crustal and mantle rheology, postseismic processes, and earthquake triggering, and planetary projects such as the full evolution of impact basins from transient crater formation through isostatic adjustment and faulting associated with lava emplacement and cooling. Andy teaches a variety of courses including the popular Geoscience in the Cinema class for non-majors and several graduate classes in geodynamics.


Briony Horgan

Briony Horgan, Assistant Professor

Briony Horgan's website

Briony Horgan received her BS in Physics from Oregon State University in 2005 and her PhD in Astronomy and Space Sciences from Cornell University in 2010, then was an Exploration Postdoctoral Fellow at Arizona State University until joining EAPS in 2014. Her research program uses data from NASA satellites and rovers, along with lab and field work back on Earth, to understand the surface processes that have shaped Mars and the Moon. She is particularly interested in using mineralogy to investigate weathering and past surface environments on Mars, as well as volcanic, sedimentary, and impact processes on both planets. Briony is a Participating Scientist on NASA's Mars Science Laboratory rover mission and a Co-I on NASA’s upcoming Mars 2020 rover mission, the first step toward Mars Sample Return. Briony loves getting to conduct field work all over the world, and enjoys outdoor activities outside of work too, including backpacking, camping, kayaking, and scuba diving.


Alexandria Johnson

Alexandria Johnson, Assistant Prof. of Practice/Research

Alexandria Johnson's website

Alexandria earned her BS in Physics, with a minor in Mathematical Sciences, from Michigan Technological University in 2009. She earned a PhD in Atmospheric Science from Purdue University in 2014 with a focus on Cloud Microphysics in Earth's atmosphere, and went on to become a Simons Foundation Postdoctoral Fellow at Massachusetts Institute of Technology studying the properties of Exoplanet and Martian cloud particles in the laboratory. Her research primarily focuses on when, where, and by what mechanisms clouds form in planetary atmospheres and the properties of those cloud particles after formation with novel laboratory based instrumentation. Planetary bodies of interest for this work include Earth, the Moon, Mars, Titan, and Exoplanets.


Brandon Johnson

Brandon Johnson, Associate Professor

Brandon Johnson's website

Brandon received his PhD in Physics from Purdue University in 2013. After a Postdoc at MIT working on the GRAIL mission and time as an Assistant Professor at Brown University, he has returned to Purdue University as an Associate Professor. His research and teaching is focused on impact cratering, the geophysics of planets, and the various processes that modify planetary surfaces. This includes interest in multiring basins formation, impact ejecta and fragmentation, the early solar system and meteorites, terrestrial bombardment history, ocean worlds, the reduction of friction during long run-out landslides and earthquakes, and understanding the lunar gravity field.


Jay Melosh

Jay Melosh, Distinguished Professor

Jay Melosh's faculty page

Jay is a Distinguished Professor of EAPS and also holds appointments in the departments of Physics and Astronomy and Aeronautical and Aerospace Engineering. He received his PhD in Physics and Geology from Caltech. His principal research interests are impact cratering, planetary tectonics, and the physics of earthquakes and landslides. His recent research includes studies of the giant impact origin of the moon, the K/T impact that extinguished the dinosaurs, the ejection of rocks from their parent bodies, and the origin and transfer of life between the planets. He was a science team member of NASA's Deep Impact mission that successfully cratered comet Tempel 1 and flew by comet Hartley 2, and he is a Co-Investigator of the GRAIL mission that returned detailed data on the Moon's gravity field. Asteroid #8216 was named "Melosh" in his honor. He was elected to the U.S. National Academy of Sciences and the American Academy of Arts and Sciences, and was awarded the McCoy award of Purdue University.


David Minton

David Minton, Associate Professor

David Minton's website

David earned his BS degree in Aerospace Engineering from NC State in 2003 and his PhD from the University of Arizona's Lunar and Planetary Laboratory in 2009. Under the tutelage of Prof. Renu Malhotra, he learned about the beauty of orbital mechanics and how we can use the dynamics of small body populations to infer the history of the early solar system. Following his PhD, he worked as a postdoc at the Southwest Research Institute in Boulder, where with Hal Levison and Bill Bottke he explored the formation and early evolution of the solar system. David joined EAPS in 2011, where his research group works on a variety of projects involving the history of the early solar system, the formation of satellites, the cratering history of airless bodies, and the physical and dynamical evolution of asteroids and comets. When not on Purdue's campus, David enjoys spending time with his wife Juliet and his children Leo and Emilia.


Stephanie Olson

Stephanie Olson, Assistant professor

Stephanie Olson's faculty page

Stephanie received her PhD in Geochemistry at the University of California, Riverside. She was then a T.C. Chamberlin Postdoctoral Fellow in the Department of the Geophysical Sciences at the University of Chicago prior to joining Purdue EAPS in 2020. Stephanie is a member of the NASA Astrobiology Institute's Alternative Earths Team, and her research focuses on extending lessons from Earth's history to NASA's search for exoplanet life. She uses biogeochemical and climate models to study the interactions between life and its environment, refine our understanding of planetary habitability, and to identify potential biosignatures that may one day provide evidence for life beyond our solar system.


Mike Sori

Mike Sori, Assistant Professor

Mike Sori's faculty page

Mike received his PhD in planetary science from MIT in 2014 after earning Bachelors degrees in math and physics from Duke University in 2008, and will join Purdue EAPS in fall 2020. Mike uses data from NASA's robotic spacecraft missions along with numerical models to study planetary geophysics and surface processes throughout the solid worlds of the solar system. Recent topics of research include studies of planetary volcanism, including cryovolcanism (ice volcanism) and ferrovolcanism (metal volcanism), the analysis of gravity and topography data to infer the structure of planetary crusts, and studies of planetary ices. He has published papers on the Moon, Mars, Ceres, Mercury, Pluto, and the moons of Uranus.


Michelle Thompson

Michelle Thompson, Assistant Professor

Michelle Thompson's faculty page

Michelle earned her BSc degrees in Geological Engineering and Biology from Queen’s University in Kingston, ON, Canada in 2011. She earned her MS and PhD from the University of Arizona’s Lunar and Planetary Laboratory in 2016 and went on to be a NASA Postdoctoral Fellow at Johnson Space Center before coming to Purdue. Her research program focuses on the analysis of returned samples, including lunar soils collected by Apollo astronauts and asteroidal particles from the Hayabusa mission. She studies how grains on the surfaces of airless planetary bodies are altered due to their exposure to interplanetary space, a process known as space weathering. She uses coordinated techniques including electron microscopy, spectroscopy, and laboratory experiments to investigate changes in the microstructure, chemistry, and optical properties of planetary materials as a result of space weathering.


Marissa Tremblay

Marissa Tremblay, Assistant Professor

Marissa Tremblay's faculty page

Marissa earned her BA in Environmental Science from Barnard College in 2012 and her PhD from the Department of Earth and Planetary Science at the University of California, Berkeley in 2017. Before coming to Purdue, she held postdoctoral positions at the University of California, Davis, and the Scottish Universities Environmental Research Centre. Marissa is a noble gas geochemist who studies Earth and planetary surface processes over a broad range of temporal and spatial scales, and her research program utilizes a combination of laboratory measurements, field work, and numerical modeling. Her planetary research includes reconstructing the thermal histories of Lunar and Martian meteorites, as well as investigating the noble gas systematics of terrestrial analog materials.


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