I am a astrophysicist with research interests ranging from the search for planets around nearby stars to the shape of the universe.
Using microwave backcground observations from the WMAP Satellite and the Atacama Cosmology Telescope", I have measured the age, shape, and composition of the universe. Our observations have played a significant role in establishing the standard model of cosmology.

I am currently co-chair of the WFIRST science team. WFIRST will study the nature of dark energy, complete the demographic survey of extrasolar planets, characterize the atmospheres of nearby planets and survey the universe with more than 100x the field of view of the Hubble Space Telescope. I have played a significant role in the design of the coronagraph and is shaping the overall mission.

I am now emeritus faculty at Princeton University. While I no longer teach, I continue to work with Princeton graduate students and postdoctoral fellows.