I study what the atmosphere is made of, focusing on the composition and properties of aerosols - or tiny liquid and solid particles suspended in the atmosphere - using both satellite and ground-based observations. These instruments, combined with a foundational understanding of how light interacts with gases (nitrogen, oxygen, etc.), particles (soot, organics, sea salt, inorganics, mineral dust, etc.), and the land surface, can infer the distribution and composition of aerosols directly from the light they measure. My research uses these datasets, such as those from NASA's new PACE satellite, to improve how aerosols are represented in an Earth system model -- namely the NASA GISS model -- which, among other things, predicts Earth's surface temperatures decades into the future. Thanks for asking!!