Jonathan I. Katz

Jonathan I. Katz

​Professor of Physics
PhD, Cornell University
research interests:
  • Astrophysics
  • Soft Matter
  • Climate
  • Applied Physics

contact info:

mailing address:

  • Washington University
    CB 1105
    One Brookings Drive
    St. Louis, MO 63130-4899

Professor Katz's current work focuses on the recently discovered astronomical Fast Radio Bursts. These brief (millisecond) bright events are believed to originate at "cosmological" distances, but their sources and mechanisms remain a mystery. He has also proposed a novel explanation of Boyajian's Star, in which its dips are the result of obscuration by dust rings in the outer Solar System.

The brightness of Fast Radio Bursts indicates a coherent emission process, like that of pulsars, and their brevity requires an origin in objects of neutron-star dimensions. However, they are too luminous to be pulsar pulses unless the pulsars are extraordinarily fast, strongly magnetized and efficient or are narrowly beamed. The novel hypothesis of beaming permits many other models, and the problem is to decide which is correct.

Undergraduate students working with Katz on weather data have set upper bounds on any increase in drought and storms as the climate warms and have developed novel descriptions of the changing frequency of temperature extremes. Other undergraduates have studied the properties of starch suspensions and found remarkable hysteresis in their shear stiffening behavior.

recent courses

Energy and Environmental Physics (Physics 344)

This intermediate-level course applies basic physics principles to this increasingly important area. It is designed for all science and engineering majors with an interest in energy and environmental issues. Topics to be covered include population trends, fossil fuel use, renewable energy sources, energy storage strategies and climate change. Particular emphasis will be given to the use of the fundamental laws of physics, such as energy conservation, as well as more general concepts such as local and global stability, chaotic behavior, probability and risk. The aim of the course is the development of analytical skills and familiarity with important concepts, in order to enable an independent and informed view of environmental problems and possible solutions. A one-year introductory physics class on the level of Physics 191-192 is required. This course may also be taken as Physics 444, which requires an additional independent project.

    Stellar Astrophysics (Physics 556)

    The focus is on the dynamics and statistical mechanics of a collection of stars which is treated as a collisionless system. The course begins with a discussion of potential theory and proceeds to discuss the density and phase space distributions of stars in star clusters and galaxies, thus leading to an understanding of the equilibria and stability of these systems. Topics such as Chandrasekhar's dynamical friction and dark matter will constitute the final topics of discussion. This course is also available for advanced undergraduates.

      Stars, Galaxies, and Cosmology (Physics 126A)

      Intended as a general survey for the non-science major. Topics include the structure and evolution of stars from birth to exotic final stages, such as red giants, white dwarfs, neutron stars, pulsars and black holes. Features of galaxies and quasars, cosmology, and the Big Bang theory.

        Classical Electrodynamics I (Physics 505)

        Classical electromagnetism in microscopic and macroscopic forms: electromagnetic fields of and forces between charged particles. Applications to electrostatic, magnetostatic, electrodynamic, and radiation problems.