My research program develops unique experiments to study the early universe.
The cosmic microwave background comes from the time photons last substantially interacted with matter in the universe, when free electrons and protons combined to form neutral hydrogen. Measurements of the minute temperature variations on the CMB give us a snapshot of the universe at this time called recombination, about 380,000 years after the Big Bang. CMB temperature variations are sensitive to the geometry and composition of the universe, and serve as the experimental foundation for our modern conception of cosmology. The figure below shows the all-sky measurement of spatial fluctuations at 143 GHz from the Planck satellite. The variations are dominated by the CMB over most of this image, except in the plane of the Galaxy visible as the stripe across the center. These state of the art CMB measurements were enabled by novel low-temperature bolometers developed by our group at Caltech and JPL.