· William L. Valentine Professor of Physics, California Institute of Technology (Caltech)1997–
· Millikan Research Fellow in Radio Astronomy, California Institute of Technology (Caltech)1985–1987
· Assistant Professor of Physics, California Institute of Technology (Caltech)1983–1989
· Ph.D. in Physics, California Institute of Technology (Caltech)1978–
· M.S. in Physics, University of Rochester1973–
· B.S. in Physics, Abilene Christian University1971–