I'm a Planetary Science/Geochemistry PhD student at UCLA
studying the thermodynamics and material properties of planetary interiors.
Hello!
I'm glad you found me!
I’m currently a PhD student in Planetary Science and Geochemistry at UCLA. Most of my research explores how materials behave under the extreme pressures and temperatures found deep inside planets.
I grew up on the North Shore of Chicago and attended the University of Missouri, where I earned a degree in Astrophysics with minors in writing and mathematics. Before graduate school, I worked at NASA's Goddard Space Flight Center, where I split my time between the Astrochemistry Laboratory and Hubble Space Telescope.
When I'm not hunting down leaks in my vacuum line or scouring my code for missing parentheses, I love spending time outside hiking, golfing, practicing yoga, and skiing. I also enjoy board games, Dungeons & Dragons, reading, and taking movies far more seriously than any reasonable person should.
Simulating Planetary Materials
I use density functional theory molecular dynamics to simulate planetary materials at extreme pressures and temperatures. My current work focuses on molten silicates mixed with hydrogen, allowing me to investigate their atomic-scale structure and behavior under conditions relevant to the molten interiors of sub-Neptune exoplanets.
From Atoms to Planets
I use simulation results to develop models for the thermodynamic and transport properties of materials. I incorporate these properties into planetary interior models to investigate the structure and evolution of planets, including whether their deep interiors can generate magnetic fields.
Planetary Phase Equilibria
I study how hydrogen is distributed among different
planetary materials and phases at high pressures and
temperatures. Understanding hydrogen partitioning,
miscibility, and phase boundaries can reveal where
hydrogen resides as magma oceans cool and how deep
interiors exchange material with planetary atmospheres.
Experimental Work
My laboratory work spans isotope geochemistry and experimental astrochemistry. I have used isotopically labeled methane experiments and high-resolution measurements on the Nu Instruments Panorama to investigate methane formation pathways and clumped-isotope signatures. At NASA Goddard, I also built an experimental system to measure spectra of high-temperature refractory condensates expected in the clouds of hot Jupiters.
Teaching & Outreach
Teaching has become an important part of my graduate experience at UCLA. Through my work as a teaching assistant, I have helped students navigate challenging scientific material, strengthen their problem-solving skills, and become more confident asking questions. I aim to create a supportive classroom environment in which complex ideas feel approachable.
After four quarters as a teaching assistant for The Solar System and Planets, I spent two additional quarters helping redesign the course from the ground up. We developed a hands-on laboratory curriculum that allowed students to explore planetary science through direct observation and experimentation. Among the labs we designed were activities using infrared cameras to investigate how light interacts with different materials and an experiment in which students built—and then dropped—dry-ice comets, using their own impact data to calculate kinetic energy.
I am also passionate about making astronomy and planetary science accessible beyond the classroom. Before graduate school, I worked in science communication for the Hubble Space Telescope, developing content for websites, social media, exhibits, and public-engagement projects.
A few of my favorite Hubble projects are linked below:
Explore the Northern Hemisphere's night sky by with Hubble's Messier Catalog!
Learn to observe astronomical objects from most locations on Earth using Hubble's Caldwell Catalog!
Discover where Hubble was pointing on any day of the year by playing with this tool I created using data from the telescope's archive!
CV
Contact
smarcum13@ucla.edu
sarah.p.marcum@gmail.com
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i = 0;
while (!deck.isInOrder()) {
print 'Iteration ' + i;
deck.shuffle();
i++;
}
print 'It took ' + i + ' iterations to sort the deck.';