Seminar: David Kaiser on Secret Clocks: The U.S. Military, Einstein’s Relativity, and the Global Positioning System

The Knight Science Journalism Program at MIT is pleased to welcome Dr. David Kaiser for a seminar on the influence of the theory of relativity on the development of GPS.

For nearly a decade, beginning in the mid-1970s, a debate unfolded among physicists and engineers over how best to include effects from Einstein’s general theory of relativity in the new military technology now known as the Global Positioning System (GPS). Although some exchanges were published in the open scientific literature, much of the debate played out behind the scenes, in memos, reports, and special review sessions arranged by the U.S. military. Theoretical physicists who had no relationship with the project criticized early efforts to incorporate relativistic effects within GPS designs, complaining that significant information was not shared by military contractors.

Other experts in relativity, who consulted more closely with the U.S. Air Force while GPS was under development, responded that the outside critics had little relevant experience with real-world engineering applications, and that their criticisms amounted to mathematical irrelevancies. Throughout the debate, few doubted that relativity — with its counterintuitive notions of space and time — needed to be taken seriously in the design and operation of GPS. Rather, they disagreed over how best to incorporate deep lessons from relativity in an engineering-relevant way, at a time when the stakes for the new military technology loomed large.

David Kaiser is Germeshausen Professor of the History of Science and Professor of Physics at MIT. He is the author of several award-winning books about modern physics, including How the Hippies Saved Physics: Science, Counterculture, and the Quantum Revival (2011) and Quantum Legacies: Dispatches from an Uncertain World (2020). His most recent book is “Well, Doc, You’re In”: Freeman Dyson’s Journey through the Universe (2022). A Fellow of the American Physical Society, Kaiser conducts research on early-universe cosmology and has also helped to design and conduct novel experiments to test the foundations of quantum theory. His work has been featured in Science, Nature, the New York Times, and the New Yorker magazine. His group’s recent efforts to conduct a “Cosmic Bell” test of quantum entanglement, together with Nobel laureate Anton Zeilinger, were featured in the documentary film Einstein’s Quantum Riddle.

Please contact Learning and Events Coordinator Claire Sadar if you are interested in attending.