Joe Lykken is a particle physicist - more specifically a "superstring theorist" - at the Fermi National Accelerator Laboratory, and a professor in the Physics Department and Enrico Fermi Institute at the University of Chicago. His research involves trying to answer some of the biggest (and simultaneously smallest) mysteries in the Universe, like why particles have the masses they do, what's the connection between quantum mechanics and gravity, and are there unseen extra dimensions in addition to the three space dimensions we normally experience.

After receiving his Ph.D. from M.I.T. in 1982, Lykken worked with Steven Weinberg on the first realistic theoretical models of "supersymmetry", which attempt to unify some of the basic forces of nature to help explain the origin of the masses of elementary particles (like electrons and protons). In 1984 he joined the stampede of particle theorists into "superstring" theory, which postulates that everything is composed entirely of superstrings ten billion billion times smaller than atomic nuclei; the result is a model of the Universe that unifies all the fundamental forces into one, and can describe most of the particles we see today. Lykken spent the next decade wrestling with deep issues of how superstrings are related both to quantum gravity and to particle physics, suggesting that effects might observable in the next generation of high-energy particle physics experiments.

Since joining the theory group at Fermilab in 1989, he has been involved in planning experimental searches for supersymmetry, the Higgs boson (a very massive, but as yet unobserved particle thought to be responsible for the masses of all the other particles), and extra dimensions (which are so tiny they are normally "hidden" from us).

Lykken has served on numerous special panels and committees charged with shaping the future of particle physics. He is chair-elect of the Division of Particles and Fields of the American Physical Society. He recently appeared on the NOVA television documentary "The Elegant Universe", and in 2003 he was elected a Fellow of the American Association for the Advancement of Science, for "imaginative and influential explorations of supersymmetry, string field theory, and the physics of extra dimensions and for inspiring others through teaching and public lectures".