Sarah Rugheimer, Ph.D.

Education: Harvard University, Ph.D., Astronomy and Astrophysics
Institution: University of St. Andrews (laboratory of Mark Claire)

SCOL Project: Modeling Atmospheres: Warming Archean Earth to Detecting Biosignatures

Atmospheric modeling allows us to examine two key areas of interest in origins research – the remote detection of life on an exoplanet and the atmospheric conditions of early Earth that gave rise to the origin of life. Theoretical modeling of atmospheres is essential in determining the size, resolution, and observing time required for a telescope to detect signs of life, or biosignatures, around an Earth-like planet orbiting a distant star. Currently all observing strategies for rocky planets rely on the ability to add multiple observations of a planet to detect atmospheric gases. This inherently assumes the planet’s atmosphere is constant in the months or years it takes for these multiple observations. However, stars can have variations in their output of high-energy light over that time. I propose to examine how the atmosphere might change due to this variation in high-energy light from the host star. I will then test how averaging multiple observations from a changing atmosphere might confuse our search for biosignatures in the future.

I also am interested in understanding the early Earth conditions that gave rise to the origin of life. We have geological evidence for warm climates and liquid water on the surface of Earth 4.4 billion years ago, yet it is difficult for current climate models to predict above freezing temperatures. This is called the Faint Young Sun Paradox. I propose to look at a potential solution to the paradox by including clouds in our climate model. In addition, a natural output of my models is the amount of high-energy light reaching the surface of a planet. This high-energy light can have both positive and negative effects on early life and chemistry. I propose to collaborate with other Simons teams to model the amount of high-energy light reaching the surface at the geological times of interest to them in their experiments.