Alexandria Johnson, Ph.D.

Education: Purdue University, Ph.D., Atmospheric Sciences
Institution: Massachusetts Institute of Technology (laboratory of Daniel Cziczo)

SCOL Project: Clouds in Exoplanet Atmospheres – Are They Blocking our View of Life Below?

The identification and characterization of extra solar planets, or exoplanets, has given context to Earth and the potential for analogs orbiting other stars. However, one long-standing question remains – Can these planets sustain life as we know it? A first step in the search for life beyond our solar system is the detection of biosignature gases; known to be produced when Earth based life metabolizes. Yet a fundamental uncertainty remains in just how easily these gases can be detected through constituents in exoplanet atmospheres such as clouds.

In this project we will use theory and laboratory based experiments to determine how cloud particles interact with light across the visible spectrum and under a wide range of atmospheric compositions, pressures, and temperatures. The aim of this project is two fold. First, to better understand the role and properties of clouds in exoplanet atmospheres. Second, use of this information to determine how clouds will directly limit our ability to detect biosignature gases. We believe this work is critical for recognizing biosignatures in the very different environments on exoplanets and that cutting edge laboratory research on exoplanet atmospheres and clouds is the best way to approach this problem. The results of this work will aid with observations of exoplanet atmospheres and biosignatures through direct imaging or transmission spectroscopy, as well as exoplanet atmospheric and radiative balance models which can give valuable information on the surface habitability of exoplanets.