- Ph.D., University of Maryland
- Active galactic nuclei
- Very long baseline interferometry (VLBI)
- Jack's main research interests focus on understanding the nature of violent astrophysical phenomena located at the centers of galaxies. The most energetic forms of "active galaxies" produce as much power as 10,000 billion Suns, all from a volume comparable to the size of the solar system. He employs radio-wave and Hubble Space Telescope observations in an effort to understand the origin and workings of these extraordinary objects.