Frontiers in Cosmology with the Cosmic Microwave Background

The Cosmic Microwave Background (CMB) is a unique and expanding window on the history and dynamics of the universe. Measurements of CMB polarization are setting new constraints on gravitational waves from cosmic inflation, yielding insights about the physics powering the very early universe. Improved CMB gravitational lensing and reionization measurements combined with upcoming galaxy survey data will yield a detection of neutrino mass, a major outstanding question in particle physics. The current and next generation of CMB instruments are being built to address these and other key science questions, and to separate the signals from galactic foregrounds. In this talk, I will discuss the Simons Observatory being developed to map the CMB to unprecedented sensitivity targeting inflation, lensing, and other key science goals. The CMB community is also coming together in the CMB-S4 process to pursue this science even further. I will also discuss BF ORE, a high-altitude balloon mission proposed to measure reionization, gravitational waves from inflation, and galactic foregrounds.