Strange New Worlds

Is there a universal divide between planets with and without atmospheres? Is it determined by incident flux and escape velocity? By studying exoplanets that straddle the “cosmic shoreline,” we are beginning to constrain the prevalence of atmospheres around rocky worlds and the mechanisms that drive their loss. JWST has already delivered a wealth of discoveries, from its first confirmed rocky exoplanet to intriguing results that favor secondary atmospheres. Building on the lessons from its first few years of science operations, new JWST programs are pushing the limits of atmospheric detection toward Earth-sized, habitable-zone planets. In this talk, I will summarize the current status of the field, highlight preliminary detections, and discuss promising paths forward. Although we have only begun to scratch the surface of rocky exoplanets, the years ahead hold the potential for transformative breakthroughs via increasingly precise studies.