About me

I am a National Science Foundation Graduate Research Fellow pursuing my Ph.D. at the University of Washington in Seattle. I am a member of two departments: Earth and Space Sciences, and Astrobiology. At the UW, I study the impact of the carbonate-silicate weathering cycle on the limits of the habitable zone with my advisor, Professor David Catling. I also conduct research at the Jet Propulsion Laboratory regarding the atmospheric conditions of ancient Mars with Dr. Renyu Hu.

Contact me via email at tbthomas@uw.edu.

Research Highlights

Modeling the carbonate-silicate weathering cycle on Earth-like planets

The carbonate-silicate weathering cycle is a feedback loop that is proposed to control the surface temperature and atmospheric CO2 of Earth on geologic timescales. If Earth is a good representative of other terrestrial exoplanets, then the carbonate-silicate cycle is likely important for determining their habitability. By leveraging what we know about Earth, we can make predictions about these exoplanets to guide our current and future searches. I do this by building computer models of the carbonate-silicate cycle, validating them against the Earth, and then applying them to other terrestrial exoplanets. I am currently investigating how another planetary process, ice-albedo feedback, interacts with the carbonate-silicate cycle in this context. I work on this at the University of Washington with Professor David Catling.

Investigating the presence of nitrogen in the atmosphere of ancient Mars

The morphology and mineralogy of ancient Mars convincingly show that liquid water existed on its surface at some point in the distant past. The temperature of Mars's surface must have been sufficiently high to prevent it from freezing, indicating that ancient Mars may have had habitable, Earth-like conditions. Because Mars is relatively far from the sun, its ancient atmosphere must have provided a substantial greenhouse effect to create high surface temperatures. However, Mars's current atmosphere is very thin, and provides almost no surface warming. This leads to questions such as what did the ancient atmosphere look like? and where did it go? A consensus has not yet been reached on what Mars's ancient atmosphere looked like, but studies have shown that CO2 alone cannot provide the necessary greenhouse effect to create habitable surface temperatures. I am currently investigating the role of N2 in the ancient Martian atmosphere with Dr. Renyu Hu at the Jet Propulsion Laboratory. We have found that there was likely a substantial amount of N2 in the atmosphere, which may enhance the greenhouse effect of CO2 and help create a habitable climate. Our paper on this investigation is currently in the review process.