Abstract
It is with great sadness that we acknowledge the recent passing of David Hochberg, an outstanding scientist and remarkable individual within the astrobiology community, who left us on December 30, 2023. David’s departure came too soon, yet his influence and legacy will persist through the work of his students, colleagues, and the research he conducted across various institutions worldwide. We express our gratitude to Astrobiology for publishing this memorial on behalf of his family, particularly his wife Inma and their two daughters, alongside his numerous colleagues and friends.
David Hochberg
David was born in Miami, FL, on February 3, 1957. He embarked on his academic journey in physics at the University of California, Berkeley, where he completed his undergraduate degree in 1979. He continued his studies at the University of Chicago, where he earned an MSc in 1982 and a PhD degree in 1985, under the supervision of Chris Quigg and Hank Thacker. Both, now emeritus professors, were the perfect mentors for an eager student full of enthusiasm and persistence. David’s doctoral research initially focused on a Monte Carlo lattice approach to quantum chromodynamics (QCD). He performed investigations in high-energy electron–proton colliders, examining scenarios where one or both particles were polarized. This work, which made him fully conversant with electroweak phenomena and the changes with scale in the strong coupling of QCD affecting the spin-dependent structure functions, represented his first significant venture into phenomenological analysis.
His postdoctoral journey first led him to the UK’s Rutherford Appleton Laboratory, followed by positions in the USA at the Bartol Research Institute at the University of Delaware and the University of Vanderbilt in Nashville. David’s global journey found its final destination in Spain, where he embraced the language and culture, making it his permanent home. There, he worked at the University of Valencia and the Autonomous University of Madrid. In the 90’s, David started collaborating with LAEFF (Laboratorio de Astrofisica Espacial y Fisica Fundamental) of INTA (Spain’s Instituto Nacional de Tecnica Aeroespacial), and from there he became a founding member of the Centro de Astrobiología (CAB) where he won a Civil Servant position as a Scientific Researcher in Spain’s Higher Research Council, the premier research-only institution in Spain.
David accumulated nearly four decades of experience applying methods of theoretical high energy and condensed matter physics to a wide variety of problems, spanning from general relativity and the electrostatic fields of DNA in solution to stochastic processes and many others. Along with numerous coworkers, David interrogated chemical evolution through nonequilibrium physicochemical processes that lead to dissipative structures/organization. His contributions to theoretical prebiotic chemistry were significantly enriched by his use of simulations of polarized forces, particularly hydrodynamic flow fields, and his work on self-assembly, autocatalysis, and self-replicating systems. He investigated the constraints imposed by thermodynamics and kinetics, the rate of entropy production, the influence of external forces, and the effect of fluctuations upon unstable nonequilibrium thermodynamic states such as those arising in spontaneous mirror symmetry breaking. He also showed that stoichiometric network analysis is an effective tool to describe the relationship between reaction networks and its boundaries.
Over the last 25 years, David progressively focused on aspects related to Spontaneous Mirror Symmetry Breaking, a pivotal element of astrobiology in the search for the origin of biological homochirality, a subject in which he clearly stood out. Thanks to his previous work in particle physics, through the study of the emergence of biological chirality, David became aware of the chemical contradictions between the microscopic and the macroscopic usual descriptions of nonlinear chemical systems. He realized the necessity to express these concepts in the framework of irreversible thermodynamics, a task that David would thoroughly investigate later in his career. He wondered how chemistry overlooked the Glansdorff-Prigogine Brussels School achievements as merely a simple historic mark, despite their value as an effective tool to model, simulate, and describe the behavior of open chemical systems, and to understand chemical evolution, selection in systems chemistry, and basic aspects of the thermodynamics of living systems. One of his last achievements was to prove the general evolution criterion theorem of the Brussels School: a forgotten and poorly understood element in thermodynamics, which could become a fundamental component in understanding and teaching chemical thermodynamics.
During his final years, David displayed great enthusiasm for one of his last scientific challenges: attempting to theoretically demonstrate the top-bottom chirality transfer taking place in certain types of curved, continuous fluid-flow reactors, which relates likewise to the problem of the origin of biological homochirality. He explored how in such curved pipes, hydrodynamic flows can develop an amount of net chirality or handedness in the fluid which can then be transmitted, via viscous shear forces, down to the level of molecular self-assembly, establishing a purely fluid-mechanical mechanism of top-down (from the fluid flow to the molecules) mirror symmetry breaking. To achieve this, he immersed himself in the rigorous study of fluid mechanics, a field relatively unexplored in his extensive career, which filled him with high motivation and provided moments of great professional satisfaction. Unfortunately, David, with his boundless enthusiasm and unyielding dedication, departed from this world in the midst of his best work, representing a significant loss for the origin-of-life scientific community.
At CAB, David coordinated the Group on Prebiotic Chemistry and Physics of Complex Systems (Fig. 1), which covered various research lines. He was the recipient of several research grants related to the aforementioned scientific problems and coauthored a large list of high-profile publications that attest to his leadership in the field. Above all, David will be remembered as a soft-spoken and thoughtful man of unwavering honesty and high ethical standards. His energetic spirit and infectious enthusiasm brought life to his dedication to unraveling the fundamental mysteries of nature. David’s brilliance shone through in his creativity and his constant stream of innovative ideas, always seeking fresh perspectives to tackle intricate problems. His contagious excitement in the moments when all the pieces fell into place was a true inspiration to all who knew him. David fostered numerous collaborations throughout his career, forming lasting friendships with many of his colleagues. He was also an outstanding mentor and guide, consistently extending a helping hand in any way he could, offering support in the most selfless manner. David leaves behind a legacy as both an exceptional scientist and a remarkable individual, forever cherished by those fortunate enough to have shared in his journey.
Prebiotic Chemistry Research Group at Centro de Astrobiología (CAB) (2020). From left to right: Natalia Blanco García, Marina Manjavacas Ropero, Eduardo Cueto Diaz, Santos Gálvez Martínez, David Hochberg, Eva Mateo Martí, Pedro Rayo Pizarroso, Marta Ruiz Bermejo, Cristina Pérez Fernández, and Jorge Vega Fernández.
Associate Editor: Sherry L. Cady