The ubiquity of water during planetary evolution

Where does water come from? How common is water throughout planetary formation and evolution? As we look at Earth’s formation and as every new exoplanet is discovered, we are drawn to the fundamental question of the origin of life and habitability. Chief among the conditions we look for is liquid water, universally considered an essential ingredient for life. In this talk I will present an integrated framework of a thermodynamic model, a set of high pressure and temperature experiments, and analyses of meteorites, to explore these questions. We utilized a self-consistent thermodynamic model to show that Earth's water, core density, and overall oxidation state can all be sourced to equilibrium between H2-rich primary atmospheres and underlying magma oceans in planetary embryos. We conducted high-pressure, high-temperature experiments showing that water readily forms during hydrogen-magma ocean interactions, and that hydrogen is highly soluble in primitive magmas. We analyzed pallasite meteorites, remnants of a disrupted, differentiated planetesimal, in an effort to look for evidence of water early in solar system history. By integrating all these studies we are able to show that water is ubiquitous, and not an accidental ingredient, but a natural consequence of planetary formation and evolution.