Astrophysics Experimentalist

After 15 years, pulsar timing yields evidence of cosmic gravitational wave background

July 3, 2023

Very Large Array telescopes in a row

The universe is humming with gravitational radiation — a very low-frequency rumble that rhythmically stretches and compresses spacetime and the matter embedded in it.

That is the conclusion of several groups of researchers from around the world who are simultaneously publishing a slew of journal articles today (Wednesday, June 28) describing more than 15 years of observations of...

Parker Solar Probe flies into the fast solar wind and finds its source

June 7, 2023

Illustration of Parker Solar Probe approaching the sun

NASA’s Parker Solar Probe has flown close enough to the sun to detect the fine structure of the solar wind close to where it is generated at the sun’s surface, revealing details that are lost as the wind exits the corona as a uniform blast of charged particles.

It’s like seeing jets of water emanating from a showerhead through the blast of water hitting...

M87 in 3D: New view of galaxy helps pin down mass of the black hole at its core

April 13, 2023

Image of a galaxy with a wire grid shape over it illustrating the M87 galaxy

Seen from Earth, the giant elliptical galaxy M87 is just a two-dimensional blob, though one that appears perfectly symmetrical and thus a favored target of amateur astronomers.
Yet, a new, highly detailed analysis of the motion of stars around its central supermassive black hole — the first black hole to be imaged by the Event Horizon Telescope...

Bright gamma ray burst confounds models of black hole birth

March 28, 2023

Diagram of a gamma ray emission emerging from a black hole showing the different types of energy in the afterglow

Last October, following one of the brightest flashes of gamma rays ever observed in the sky, telescopes around the world captured a wealth of data from an event that is thought to herald the collapse of a massive star and the birth of a black hole.

But that fire hose of data demonstrated clearly that...

Stuart Bale


Stuart D. Bale received B.A. and Ph.D. degrees from the University of Minnesota in 1989 and 1994, respectively. After three years of postdoctoral work at Queen Mary College, University of London, he came to a research position at the Space Sciences Laboratory (SSL) at Berkeley. He joined the Physics faculty in 2004 and is the Director of SSL. He has held visiting appointments at the Observatoire de Paris, Meudon (Univ. Paris VII), LPCE/CNRS in Orleans, France, the University of Sydney, and Imperial College and Queen Mary University London. He is a recipient of the 2003 Presidential Early...

Steven Kahn

Dean of Mathematical & Physical Sciences, Professor of Physics, Professor of Astronomy
Steven M. Kahn is a Professor of Physics and Astronomy. He previously served on the faculty in these departments from 1984-98, but returned to Berkeley in 2022 to take up the position of Dean of Mathematical and Physical Sciences. Kahn received his A.B. (summa cum laude) from Columbia in 1975 and his Ph.D. in physics at Berkeley in 1980. In addition to Berkeley, he has served on the faculties of Columbia, where he was the I.I. Rabi Professor of Physics, and at Stanford, where he was the Cassius Lamb Kirk Professor in the Natural Sciences. Kahn is an experimental astrophysicist and cosmologist...

Stuart Bale Awarded AGU Fellowship

September 26, 2022

Stuart Bale in the lab

Berkeley Physics is delighted to announce that Professor Stuart Bale is among the 2022 Class of AGU Fellows.

The American Geophysical Union (AGU) recognizes each awardee for their remarkable innovation and/or sustained scientific impact, as well as their efforts in fostering...

Herbert Steiner

Professor Emeritus

Herbert Steiner received his B.S. in Engineering Physics in 1951 and his Ph.D. in Physics in January 1956, both from the University of California, Berkeley. From 1956 to 1960 he was a research physicist at the Lawrence Berkeley National Laboratory and a lecturer in the Berkeley Department of Physics. After a year as a Guggenheim and Ford Foundation Fellow at CERN in Geneva, Switzerland he joined the Berkeley Physics faculty in 1961. He served as chairman of the Physics Department from 1992 to 1995. He is a fellow of the American Physical Society and the recipient of an Alexander von...

Adrian Lee


Adrian Lee joined the faculty in July 2000. He received his B.A. in physics from Columbia University in 1986 and his Ph.D. from Stanford University in 1993. At Stanford, he worked with Blas Cabrera on the early development of an experiment to detect non-baryonic dark matter. Following graduate school, Lee became a postdoctoral fellow at Stanford Medical School, where he worked on mapping functions in the human brain using magnetic resonance imaging. Subsequently, from 1994 to 2000, he did postdoctoral work at U.C. Berkeley with Paul Richards measuring spatial anisotropy in the 2.7 K cosmic...

William Holzapfel


I was born March 15, 1965 in Pittsburgh PA. After surviving an early program of experimentation with motorcycles and explosives, I went on to receive a B.A. in physics from Rensselaer Polytechnic Institute in 1987. My graduate studies were completed in 1996 with a Ph.D. in physics from Berkeley. I was then a Fermi-McCormick fellow at the University of Chicago until I joined the faculty in 1998.

Research Interests

My primary research interests are in the measurement and interpretation of anisotropies of the cosmic microwave background (CMB). Primary anisotropies of the CMB provide a...