Our new co-director: Dr Frances Rivera-Hernández


Please join me in welcoming onboard the new co-director of the Georgia Tech Astrobiology Program: Dr. Frances Rivera-Hernández ! Dr. Rivera-Hernández will be leading the Planetary Science and Astrobiology Seminar Series starting this fall 2021. Read more about Dr. Rivera-Hernández and her exciting research below!

PSAS: Book talk – Sociology of Spacecraft Mission Teams


Professor Vertesi specializes in the sociology of science, knowledge, and technology. Her primary research site is with NASA’s robotic spacecraft teams as an ethnographer. Her books, Seeing like a Rover: Images and Interaction on the Mars Exploration Rover Mission (Chicago, 2015) and Shaping Science: Organizations, Decisions, and Culture on NASA’s Teams (Chicago, 2020) draws on her ethnographic studies of missions to Mars, Saturn, and the outer planets to examine how organizations matter to scientific discovery. Vertesi is also a leader in digital sociology, whether studying computational systems in social life, shifting research methods online, or applying social insights to build technologies along different lines. She holds a Master’s degree from Cambridge and a PhD from Cornell, has received several grants from the National Science Foundation, and has been awarded top prizes for her work from the ASA’s Science, Knowledge and Technology Section and Communication, Information Technology and Media Section, and the Society for Social Studies of Science.

Janet Vertesi,
Associate Professor, Department of Sociology at Princeton University

PSAS: Weather on extrasolar worlds


As observations of exoplanet atmospheres have grown in number and fidelity, spanning a larger
wavelength range at ever-higher spectral resolution, they have provided unprecedented constraints
for exoplanet atmospheric models. These datasets allow us to probe their atmospheric properties,
including the composition and spatial distribution of clouds. In this talk I will discuss efforts to
understand the advective, radiative and chemical processes taking place in giant exoplanet
atmospheres via three-dimensional (3D) circulation modeling, and how they serve to inform
comparative exoplanetology studies of transiting giant planets using the Spitzer and Hubble Space
Telescopes (and soon the James Webb Space Telescope). I will also discuss how our efforts to
understand giant planets can be extended to our understanding the climate of potentially habitable
worlds, particularly those transiting M-dwarfs.

Tiffany Kataria,
Scientist, NASA Jet Propulsion Laboratory Exoplanet Discovery and Science

PSAS: A microbe’s-eye view of cryosphere carbonates


The history of life on Earth is dominated by microbial communities, and aspects of their evolving
relationship with surface environments can be preserved by carbonates. In this talk, I focus on lakes
Joyce and Fryxell of the McMurdo Dry Valleys, Antarctica, to assess attributes of cryosphere
environments that influence microbial carbonates: namely ice cover, cold temperatures and
seasonality. Microbial mats in both of these lakes contain abundant carbonates, but differ in redox
chemistry and the degree of apparent biological influence on carbonate precipitation. Though such
cryosphere carbonates do not contribute significantly to the sedimentary record, these rare examples from modern environments provide necessary models for reconstruction of long term paleolake climate records and inform paleoenvironmental interpretations of ancient cryospheres like Snowball Earth episodes.

Tyler Mackey,
Assistant Professor at the University of New Mexico in the Department of Earth and Planetary Sciences

PSAS: Planetary Scale Microbial Dispersal


Earth’s atmosphere provides a thin barrier to the severe conditions of space. Globally, terrestrial microorganisms from our planet’s surface move through the blanketing atmosphere, analogous to how marine microbes drift through oceans. Whereas a century of exploration has allowed oceanographers to characterize marine life at nearly every depth, the same is not true for the “ocean” of air above our heads. High‐altitude exploration has been severely constrained by a shortage of reliable experimental systems. This seminar will discuss recent advances in the microbiological exploration of Earth’s atmosphere with the use of high-flying NASA aircraft and scientific balloons. Discoveries from these platforms are relevant to astrobiology in two fundamental ways: (1) Earth’s stratosphere is a natural laboratory for assessing the potential survivability of microbes on the surface of Mars which possesses a similar combination of conditions (high radiation levels and ultralow temperature, pressure & relative humidity); and (2) Methods for reliably collecting and detecting trace levels of microbial biomass at extreme altitudes can contribute to life detection strategies for other solar system targets.

David J. Smith
NASA microbiologist who founded the Aerobiology Laboratory at Ames Research Center

PSAS: The Jupiter polar cyclones as seen by almost 4 years of Juno observations


The NASA spacecraft Juno discovered the circumpolar cyclone structures on Jupiter in 2017, and it has been monitoring their evolution ever since. These cyclones are organized in structures shaped like regular polygons. I will discuss the evolution of these structures as seen by Juno from February 2017 to November 2020  focusing on the data provided by the JIRAM instrument (Jovian InfraRed auroral mapper). Through these observations we have been able to monitor the properties, position and evolution of cyclonic and anticyclonic structures at latitudes above 80° both in the North and South poles of Jupiter.  

Fundamental questions concerning Jovian cyclogenesis concern the formation mechanism and whether these cyclones are deep or shallow structures. JIRAM’s measurements show that any change in a structure is an extremely unlikely event on an annual scale, which has only happened once, and only temporarily in 2019. Neither the merging of two cyclones, nor the disappearing/creation of one stable cyclone has ever been observed. 

Finally, I will discuss recent numerical studies relevant to both Jupiter and Saturn and how their results ‘fit’  JIRAM observations and possible steps forward to solve the deep – shallow conundrum.

Annalisa Bracco,

Professor School of Earth and Atmospheric Sciences, Georgia Institute of Technology