The measure of a man

John Archibald Wheeler embodied the golden age of physics. He was perhaps unique in having made foundational contributions to both pillars of modern physics: quantum mechanics and general relativity. He helped develop the theory of nuclear fission, and then was an important participant in the Manhattan project. He discussed quantum mechanics with Bohr, relativity with Einstein, and electrodynamics with his student, Feynman. One of Wheeler’s particularly nice calculations (on asymmetrical nuclei) got scooped because Bohr sat on it too long. The person that scooped them, James Rainwater, subsequently won the Nobel prize for the result. In Feynman’s Nobel lecture, he credits Wheeler with many of the key insights. Wheeler mentored over one hundred students, and those students (and grand-students) now populate leading physics departments throughout the world. In addition to his facility with physics, Wheeler displayed a wondrous command over language. His career is partially encapsulated in his coinages: wormhole, black hole, the planck length and time, quantum foam, the sum over histories, the S-matrix, It from Bit, the wavefunction of the Universe.

John Wheeler passed away almost exactly a year ago. In commemoration of his tremendous contributions to physics, the current edition of Physics Today (the monthly magazine of the American Physical Society) is dedicated entirely to his memory. [Sadly, only select articles are public, which I find incomprehensible.] The issue includes an article on Wheeler’s early work on particles (written by Ken Ford), as well as one on his later work on fields, gravity, and information (by Charlie Misner, Kip Thorne, and Wojciech Zurek). There are also two reprints of articles authored by Wheeler, one on nuclear fission (describing his pioneering work with Niels Bohr), and one “introducing” black holes (written with Remo Ruffini). As a sign of Wheeler’s enduring legacy, the magazine ends with an article (by Terry Christensen) focused on his tremendous mentorship.

It is impossible to summarize Wheeler’s impact, both as a physicist and as a human being. How do you reduce someone to a few paragraphs, or a few articles, or a few interviews? Wheeler was unique in his insight, his breadth, his generosity, and his humanity. For those that were fortunate enough to spend time with him, he left an indelible mark. As one of Wheeler’s students put it in the acknowledgment to their thesis:

It is a pleasure to acknowledge the tremendous support and encouragement given to me by John A. Wheeler. Over the last two years he has introduced me to the world of physics research and shaped the way I think about physics. I have benefited greatly, both as a physicist and as a person, from his example, and will carry this with me always. John Wheeler has had a profound impact on my life and I am deeply indebted.

I wrote that over 15 years ago, and it is no less true today.