Jaco de Swart
University of Amsterdam
Smithsonian National Air and Space Museum
How do we know the universe? During the Cold War, the astronomical sciences became an epicenter for questions pushing the limits of what was known. Scientists developed new practices to empirically probe the universe's most unreachable domains: life on nearby planets, extreme stellar objects, and invisible mass that could fill the cosmos. In each instance, the distant universe was drawn in close. But how did these scientists make the inaccessible accessible? What tools and methods did they use to obtain knowledge about other worlds and far-away phenomena? And how did the remote universe and its contents become objects of scientific interest in the first place?
This session presents different historical approaches to explore the variety of ways scientists produced knowledge about the universe in the second half of the 20th century. Similar to how the study of the universe brought together different scales-from mosses to planets, to black holes and big bangs-this session brings together different historiographical scopes-from institutions to disciplines, to practices and politics. These four papers consider visualization practices, discipline formation, Soviet science, and Cold-War military contexts. Each offers a fruitful entry point to understanding ways of knowing the universe.
Military Models of Life on Mars: Air Force Astrobiology in the Early Cold War
Hubertus Strughold began studying the possibility of life on Mars in 1950. In his 1953 book The Green and Red Planet, he predicted Mars was covered in a simple yet hardy vegetation, similar to lichens. To explore this experimentally, he built a series of airtight jars capable of replicating the thin air, arid soil, and frigid nights thought to exist on the planet's surface. Then he added simple forms of Earth life to see if any could survive these harsh conditions. Strughold wasn't working for the National Aeronautics and Space Administration (NASA) (which didn't exist yet) or a major research university. He created this life-on-Mars experiment for the United States Air Force (USAF). In the long history of speculation about life on other worlds, Strughold's "Mars Jars" are significant as the first environmental simulations, but more importantly they are unique in their overt military goals.
This paper explores how military patronage shaped Strughold's early astrobiology studies. He framed these experiments as part of the wider U.S. military push to operationalize a range of extreme environments for the Cold War. These tiny military models made Mars seem knowable, controllable, and positioned it as a strategic site requiring a U.S military presence. When Strughold found that certain microbes could survive and even thrive inside Mars Jars, he did not link this discovery to the centuries old "Plurality of Worlds" debate among astronomers and philosophers, or to questions surrounding the origin of life later posed by NASA exobiologists. Instead, he wondered how future Air Force astronauts dispatched to Mars could use any life discovered there to establish "an extraterrestrial observation or exploratory base." I unpack this instrumentalist, anthropocentric regard for extraterrestrial life, and show how it lingers in current plans for missions to Mars. Strughold's USAF astrobiology program was superseded in the 1960s by NASA's exobiology community, but the tool he inv
Blue Vegetation on the Red Planet: Soviet Astrobotany and Early Earth Analogues
University of New Mexico
While many accounts of the history of astrobiology begin in recent decades, and often focus on the West, the emergence of the Soviet field of "astrobotany" in the 1940s offers a competing history for the emergence of early ideas of earthly analogues for Martian environments. In an effort to study the probable vegetation of Mars, astrobotanist G. A. Tikhov sought to study "the optical properties of terrestrial plants in connection with problems of the limits of physical conditions under which plant life can exist," by spectroscopically studying high-altitude and high-latitude plants in the mountains of Kazakhstan. Tikhov concluded that such efforts would make it "feasible to make more definite conclusions about the vegetation on Mars and even, perhaps, to say to which families of terrestrial plants the Martian plants come closest." Firmly rooted in the insights and principles of dialectical materialism, Tikhov argued for a tight interconnection between the study of life on earth and on other planets, and claimed astrobotany as a fundamentally practical science that avoided mere speculation while also offering clear paths forward for terrestrial agronomy. It was out of such work and the prospect for "studying microorganic life on the giant planets" that astrobotany first began to be called "astrobiology."
The Event Horizon as a Vanishing Point: Visual Representations in Black Hole Research and Communication, 1973-2019
University of Cambridge
Within the span of a day, the first image of the shadow of a black hole had become an icon, spread across social media, newspapers, and TV. Although the image released by the Event Horizon Telescope Collaboration (EHTC) was the first of its kind as it was based on observation, illustrations depicting black holes as though they were observed date back to the 1970s. An important example is a detailed drawing produced by astrophysicist Jean-Pierre Luminet in 1978, and semi-schematic illustrations had been published earlier in the decade.
While visualisations based on simulations of black holes emerged, other kinds of visual representations were still used to facilitate an intuitive understanding of black holes. Before the release of imaging based on observation, using visual representations of various genres of scientific imaging together was an important part of the way members of the EHTC tried to communicate the space around a black hole, and how it would look in a potential image from observation. There was not a clear demarcation between images used in research settings and for communication as the same visual representations were often used in research, in peer-reviewed literature, and in communication to non-specialists. After the release of the EHTC image, differences between various kinds of visual representations came to play a part in the reception of the first image based on observation. Stylistic changes to other visual representations of black holes based on the EHTC image have also started to appear, indicating changes to the iconography of black holes.
How the Universe Went Missing: Dark Matter and the Rise of Physical Cosmology
Jaco de Swart
University of Amsterdam
In 1974, two independent research groups in the U.S. and Estonia concluded on the existence of "missing mass": a yet-unseen type of matter distributed throughout the universe. By gathering determinations of masses of galaxies from a variety of astronomical sub-fields, both groups independently showed that the majority of the cosmic mass budget was indeed "missing". Despite it still being undetected, their elusive hypothesized mass - currently known as dark matter - has become one of the pillars of the 21st-century cosmological canon.
This paper explores the conditions under which dark matter came to matter in 1974. Unprecedented institutional changes and observational advances rocked astronomy in the 1960s, pushing many young scholars to engage in a "physics of the universe". This new generation of astro-physicists - part astronomers, part physicists - came to use newly developed tools and theories to address scales beyond the galaxy. Within this hybrid environment of "physical cosmology", different astronomical scales were drawn together. On the basis of oral history interviews, I show how, only within this novel practice, readily-available observations were translated into evidence for the existence of missing mass. Tracing how the majority of the universe went missing, then, opens up a way to understand how the universe was found in the first place - that is, how contemporary cosmological practice, and its ways of drawing knowledge from the universe, was established in the early 1970s.