I am a planetary scientist and astrobiologist at the Carl Sagan Institute at the Cornell University Department of Astronomy. I model atmospheric climates of rocky planets both within and outside our solar system. I infer the potential habitability of exoplanets by employing the concept of the habitable zone, which is the circular region around a star in which liquid water could exist on the surface of a rocky planet. In our solar system, I am most interested in constructing atmospheric models that explain the abundant geologic evidence that suggests that Mars may have once possessed a considerably warmer, wetter climate than that of present. Thus, my research helps demonstrate that Mars may have supported conditions conducive to life, and answering this question is another great reason to send humans there.