Rebecca Charbonneau. Credit: Jim Braatz, photographer
We are lucky to host interviews with many wonderful authors of books on the history of physics, but it is with particular excitement that we share today’s article featuring the work of historian Dr. Rebecca Charbonneau, who recently joined us at the American Institute of Physics. Dr. Charbonneau is also an affiliate of the National Radio Astronomy Observatory and the St. Andrews SETI Post-Detection Hub. She holds an MSc (Master of Science) in the history of science, medicine, and technology from the University of Oxford and a PhD in the history and philosophy of science from the University of Cambridge.
Dr. Charbonneau’s new book, Mixed Signals: Alien Communication Across the Iron Curtain, was released on January 14, 2025, and delves into the complicated and little-known alliance between US and USSR radio astronomers during the Cold War. Without further ado: the interview!
Corinne Mona: Tell us about the book. When and why did you decide to write it?
Rebecca Charbonneau: Mixed Signals: Alien Communication Across the Iron Curtain explores the surprising ways Cold War geopolitics intersected with the scientific search for extraterrestrial intelligence (SETI). It tells the story of how scientists navigated ideological divides, nuclear tensions, and cultural barriers to collaborate on what might be the most universal question of all: are we alone in the universe?
The book draws from my own fascination with the Cold War, which has been a part of my life since childhood. Growing up in a Cuban-American family, the Cold War was always present—stories of family members fleeing communism in Cuba to Miami, only to live under the specter of the Cuban Missile Crisis in Florida.
But my interest in the specific topic of SETI began when I was a graduate student at Oxford and stumbled upon a copy of Intelligent Life in the Universe by Carl Sagan and Iosif Shklovsky in the Bodleian Library. It struck me as remarkable that an American and a Soviet scientist had co-written a book in the 1960s, at the height of Cold War and Space Race tensions, on the subject of ET [extraterrestrial life], of all things. That discovery sent me down a rabbit hole of international scientific collaboration, espionage, the looming threat of nuclear armageddon, and the challenges of communication—whether across ideological divides or across the vacuum of space.
I wanted to write this book because it’s about more than just SETI or the Cold War; it’s about how political and cultural environments shape science and, just as importantly, how science and scientists shape the world in turn. I hope it offers readers a new way to think about the interplay of science, politics, and culture, and how our desire for connection, knowledge, and communication perseveres even in the face of great barriers and challenges.
CM: Can you discuss what it’s like to be an academic focusing on the history of SETI (the search for extraterrestrial life)? Are there others out there (pun!) doing what you do? What is the history-of-SETI community like?
RC: There are not many historians of SETI out there! I was inspired by the work of former NASA Chief Historian Steve Dick, whose pioneering scholarship on the history of the extraterrestrial life debate introduced me to the potential of this field. While there isn’t exactly a “history of SETI” community, there is what we might call a “Social SETI” community. This group includes anthropologists, historians, psychologists, sociologists, theologians, and others who study the social, cultural, and ethical dimensions of SETI.
History of SETI (or as it is sometimes also known, Technosignature research) is quite possibly one of the best branches of history of science to work in because, unlike many other areas of the physical sciences, there is an active and vibrant effort to create an interdisciplinary community between the physical and social dimensions of the field. That means it is quite easy and welcome for me to work directly with my colleagues in the astrophysics community. It is a tight knit and rather joyful community. There is no better conference in the world than a SETI conference. You will meet people from myriad academic backgrounds, all of whom have a different entry point into the same fascinating question. I have had conference lunches [where I] sat at the same table as a judge from the US District Court of Appeals, a theologian, and physicist studying gravitational waves. I’m sure you can imagine all the wonderful directions the conversation might go in.
CM: While your book sounds potentially fascinating to anyone, did you have an audience in mind for it while writing?
RC: I had two main audiences in mind, besides the educated public. First, of course, was historians, and especially historians of science. My goal here was both to introduce a novel entry into the history of the Cold War as well as introduce SETI more firmly to the historical literature. As I mentioned, you can pretty much count the number of historians who have dedicated their research to SETI on one hand, which is a real shame as it is an incredibly rich and fascinating history. I do hope Mixed Signals encourages more historians to consider working on SETI—we need help!
My second intended audience was SETI scientists themselves, and astronomers more broadly as well. SETI scientists are doing work in a field that requires immense technical expertise but also a great deal of imagination and philosophical reflection. I wanted to provide them with a historical context for their efforts, showing how their work is connected to broader cultural, political, and intellectual currents. By understanding the historical forces that shaped their field—both its opportunities and its challenges—I hope SETI scientists can better appreciate their place in a long and fascinating history but also use their knowledge of that history as a tool that allows them to interrogate their own assumptions and biases and approach the search for extraterrestrial intelligence with greater creativity and self-awareness.
I also wanted to show astronomers and scientists more generally that history has something meaningful to offer their field. Engaging with the history of their discipline can illuminate not just where they’ve been but also where they might go next, providing valuable insights into how scientific communities form, evolve, and collaborate across boundaries. I find this especially relevant in today’s scientific landscape, which is really no less riddled with challenges and barriers than the Cold War period.
CM: Which libraries and archives did you consult during the course of your research?
RC: I primarily relied on the absolutely wonderful archives of the National Radio Astronomy Observatory. Beyond that, I also used the NASA Historical Reference Collection, the Wellcome Collection and Library in London (they hold the papers of Sir Francis Crick, who attended a key SETI conference in the Soviet Union in 1971), as well as the many libraries of Oxford and Cambridge. Outside of libraries and archives, I conducted oral history interviews in the US, Britain, and Russia (funded in part by an AIP oral history grant-in-aid), and relied on the private papers and collections of the scientists I worked with.
CM: SETI is serious science that has a way of capturing imaginations to a greater extent than perhaps some other areas of the physical sciences. Do you feel like this is a benefit when telling people about the book? Is it hard to distance yourself from any pseudoscience aspects?
RC: As a historian, it’s always a pleasure when people show genuine interest in your research and writing. I’m delighted that SETI—and the topic of extraterrestrial life more broadly—captures people’s imaginations. It’s a fantastic entry point for conversations about the history of radio astronomy (the field in which most SETI searches have historically been conducted) and for engaging with broader philosophical questions, such as, “What does it really mean to define ‘intelligent’ life?”
While SETI is firmly rooted in the world of astronomy and other physical and social sciences (like astrobiology, anthropology, etc), it’s true that it occasionally gets lumped in with pseudoscience and conspiracy theories, particularly ufology [the study of UFOs]. However, I am not a ufologist, and as a historian of astronomy, my focus tends to be on what happens beyond our atmosphere rather than inside it. So while I am not particularly interested, myself, in the world of UAPs [unidentified anomalous phenomena], the public fascination with SETI is a benefit—it sparks curiosity and opens the door to meaningful discussions about the intersection of science, culture, and philosophy. And while misconceptions about SETI exist, they’re often just starting points for dispelling myths and inviting people to appreciate the profound scientific and philosophical pursuit that SETI represents.
CM: What questions do you hope that readers will ask after they’ve read the book?
RC: I hope my readers are left with a million questions. There is so much more work to be done in this area of the history of science. I hope they ask:
CM: What future projects and areas of research are you excited about?
RC: I’m thrilled to have joined the American Institute of Physics a few months ago, where I get to continue my work researching and sharing the history of astronomy with both astronomers and historians. It’s incredibly rewarding to collaborate with scientists and help preserve these fascinating stories. My current research explores a range of topics in the history of astronomy, including the development of very long baseline interferometry and the evolution of exoplanet science, while still maintaining a strong focus on SETI. My next manuscript will delve into the intersection of science policy and technosignature science, examining the development of post-detection protocols and the broader dialogue around discovery and the dissemination of scientific knowledge in astronomy.
CM: I have to ask: do you think we’re alone?
RC: I have no more authority or ability to answer this question than anybody else on the planet but if you want a personal opinion and nothing more—I think human beings are probably not the only intelligent technological beings to ever exist (or that ever will exist) in the universe. But I am less sure about whether or not we will ever successfully come into contact with others. We have enough trouble trying to communicate just among ourselves!
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