Scientific Colloquium
November 18, 2011


"Do the Building Blocks of Life Exist in Titan’s Atmosphere: Lessons from the Lab"

Does Titan's atmosphere contain the basic building blocks of life? In this talk I will discuss how recent measurements by NASA's Cassini spacecraft and parallel laboratory chemistry investigations are revealing the surprising complexity of the atmosphere of Saturn's giant moon.

Titan is unique in the solar system because it is the only moon with a substantial atmosphere. Composed primarily of N2 and with a surface pressure 50% greater than on the surface of Earth, Titan’s atmosphere is the most similar atmosphere in the solar system to that of Earth. However, Titan’s atmosphere has only small amounts of oxygen-containing molecules, which means that it may most strongly resemble the atmosphere of the early Earth. These similarities provide us with the opportunity to study chemical processes analogous to those that may have enabled the origin of life on Earth.

Cassini's instruments are now revealing the true diversity of Titan's atmosphere, which is significantly more complex at much higher altitudes than anticipated. In laboratory simulations of Titan’s atmosphere, similar to the Miller-Urey experiment, mixtures of gases are irradiated resulting in the formation of numerous complex organic molecules. In a recent experiment, we’ve shown that the addition of carbon monoxide (which is present in Titan’s atmosphere) to the standard N2/CH4 Titan simulation gas mixture provides enough oxygen to allow for the formation of amino acids and nucleotide bases used by life on Earth.

I will review the current state of our understanding of Titan's oxygen chemistry and briefly discuss how future missions to Titan could be designed to answer questions that will remain after Cassini.

About the Speaker:

Dr. Sarah M. Hörst is currently a NSF Astronomy and Astrophysics Postdoctoral Fellow at the Cooperative Institute for Research in Environmental Sciences (CIRES) at the University of Colorado-Boulder. She received a B.S. in Planetary Science (and literature) from the California Institute of Technology in 2004 and a Ph.D in Planetary Sciences from the University of Arizona in 2011. Her current research interests include understanding the organic chemistry occurring in Titan's atmosphere and the formation and composition of aerosols in planetary atmospheres.




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