The Origin of Earth: Lessons from Multi-Planet Systems
Prof. Lauren Weiss
Department of Physics and Astronomy
University of Notre Dame
How did we get here? Are we alone? A fundamental milestone in answering these questions is the origin of Earth, an event that we are just now contextualizing, thanks to the discovery of thousands of exoplanets. Using telescopes, my group is investigating how the thousands of known planetary systems formed, what they reveal about the origin of our solar system, and whether these distant worlds could harbor life. As part of our investigation, we are discovering Earth-sized planets with rocky surfaces amenable to life as we know it. Many of these worlds form in intriguing patterns of regular sizes and orbital spacing. These patterns, which we call “peas in a pod,” are mostly absent from the solar system, but resemble a theorized early generation of solar system planets thought to have been destroyed by Jupiter. Meanwhile, Earth’s extensive surface liquid water, which is a key aspect of its suitability for life, is attributed to the gravitational influence of Jupiter. How was Earth’s water delivered, and can we expect the small, rocky exoplanets we have discovered to be similarly endowed? By combing the cosmos to search for patterns in multi-planet systems and trace the role of Jupiter analogs in providing rocky planets with water, we hope to contextualize the origin of Earth and guide humanity’s next steps in the search for life.