Goldberg is a researcher in theoretical cosmology and astrophysics, focusing primarily in the field of gravitational lensing.  He is the author (with former student, Jeff Blomquist) of A User's Guide to the Universe: Surviving the Perils of Black Holes, Time Paradoxes and Quantum Uncertainty, a popular account of recent advances in physics and astronomy, and of The Universe in the Rearview Mirror (2013).