What the History of Astronomy Can Teach Us about the Unknown

Humanity has long wished to know the universe. This desire has been present in nearly every civilization, culture, or community of human beings. Knowing the universe has always been extremely challenging, notwithstanding diverse approaches to the task—scientific reasoning, ancestral respect, the identification and worship of divinities, to name but a few. Nevertheless, there is a common gesture when we connect to the universe. No matter in what time or place, humans look up to the stars and wonder. We exhibit a common attitude as well, overwhelmed by how much we do not know about our own universe.

In some way, this sense of being overwhelmed must have been present in ancient cultures, too. In our own era, whenever we can enjoy the darkness of the night, this gesture and this attitude have not changed that much. Despite all modern astronomy’s advanced technology, there is still the looking up and the wondering about all the celestial phenomena we do not know.

If there is continuity in relating to the stars, though, there are some other things that have changed, in particular with regard to how we produce astronomical knowledge and, even more broadly, scientific knowledge. Those changes are not simply technological. There are two episodes in the history of astronomy that I find particularly interesting to illustrate this point.

By the end of the nineteenth century, the astronomer William Wallace Campbell, working at the Lick Observatory in California, wanted to solve what he termed the “sidereal problem.” At first, I thought this had to be a very well-known problem in astronomy. Even if more than a century later it held little interest for astronomers, they would certainly know what Campbell meant with this concept. But they did not. To find out what was at issue, I had to search through Campbell’s own publications and records.

The sidereal problem was somehow complicated. In one of his notes, he pointed to uncertainty about the position of the beholder: “It is well known that the observed positions and motions of celestial objects are influenced not only by the motions of the objects themselves, but also by motions of the observer.”1 Moreover, Campbell insisted that there were three motions: rotation, which they could explain and measure very well; revolution, which still had a margin of error, but which he trusted would soon be resolved; and the motion of the solar system through space. The sidereal problem combined the movements of the solar system, of our planet, and of the humans trying to understand them.

To cope with this task, Campbell embarked on an ambitious project. He constructed a spectrograph, raised funds, convinced scientists and authorities, and designed a mission to go to the Southern Hemisphere and build an observatory there. By doing so, he could compare observations and measurements—specifically, radial velocities—from both hemispheres. He and his team at the Lick Observatory acknowledged how little they knew about Southern stars. As Heber Curtis, one of the astronomers, would later say, the Southern skies contained “many virgin fields which offer rich returns to the exploring astronomer.”2 The team hoped to see what no astronomer had seen before.

The plan moved forward. They chose Chile as their destination; however, at the last moment, Campbell could not travel and lead the mission. Appointed director of the Lick Observatory, he severely injured himself testing one of the mirrors right before the trip. Frustrated, he stayed in California and sent his assistant, William Wright, as the mission’s acting lead astronomer.

To deal with the uncertainties of trying to answer a complicated astronomical question, Campbell had put together several human, financial, and technological efforts. After this preparation, the adventure began. Wright and the rest of the team sailed from San Francisco to Valparaiso in 1903. They shipped all the equipment they needed: mirrors, spectrograph, plates, and even a dome. The astronomers spent more than two months at sea, constantly checking their instruments, before they arrived in an unfamiliar South American country. Once there, they had to get to the capital city, find a suitable location, and build their observatory, all while dealing with a foreign society.3

Pictured here are the astronomical instruments (telescope and spectrograph) that the astronomers from the Lick observatory took to Chile in 1903. The installation was called the 37-inch Mills Reflector after Darius Ogden Mills, who funded the expedition. Source: The Adolfo Stahl Lectures in Astronomy (San Francisco, CA: Stanford University press, 1919), plate xxvi (after p. 114)

The point of this fascinating adventure was to study an unknown portion of the universe. They had a scientific plan, to measure the radial velocities of brighter stars, but they did not have a preconceived notion of what they would find. In fact, the mission, initially planned for two or three years, lasted twenty-six. The astronomers worked intensely during that period, but the sidereal problem was not even mentioned in their findings. As important as that had been in Campbell’s motivation and justification for going south, once the team was there, the sidereal problem seemed to have vanished. Their work centered on studying all the stars they could not see from California, and they discovered interesting information about binary stars.

Chile Southern Station of the Lick Observatory, located on the second summit of San Cristobal Hill in Santiago. The small cabin next to the observatory was the office of the astronomer. Visible in the background, on the peak to the right, is the statue of the Virgin Mary, inaugurated in 1908. Source: UC Santa Cruz Library, Digital Collections.

In 1909, Curtis led an expedition to the Atacama Desert. He was impressed by the purity of the skies there, but the isolation was too severe at the time to think of building a station in that location. Nevertheless, he recorded his entire trip in what became known as the Curtis Report.4

Although the group faced several financial issues during the mission’s stay in Chile, the value of their work was never called into question. The argument that there was too much to apprehend was enough for an astronomical mission and, more surprising, for their patrons too.

Several decades later, in the 1960s, with completely different technology available, postwar astronomers in Europe and the United States were interested in reaching Southern skies. Again, the reason was simple. They had a fair amount of information about the celestial Northern Hemisphere, but very little about Southern celestial phenomena. By this point, they never referred to the sidereal problem. They had two other focal points instead. From the South it was possible to observe the Magellanic Clouds and the center of the Milky Way.

Again, enormous efforts to go South began. Astronomers in Western Europe put together a collaborative project, which later culminated in the European Southern Observatory (ESO). Their plan was to establish a research station in South Africa. After all, as they noted at the time, “The study of the southern celestial hemisphere is much less advanced than that of the northern hemisphere. Most of the big instruments are located in the northern terrestrial hemisphere, particularly those at Mount Palomar.”5

At the same time, and despite having the most powerful telescopes at the time (at Mount Palomar), the Americans made progress with their own plan to establish an observatory in the South. For them, Latin America was the most reasonable region to look for a place. After a series of negotiations, they decided on Chile and sent the German astronomer Jürgen Stock to do site testing.

Once again, the astronomical assignment involved wandering around mountains, carrying delicate equipment, making sure they had mules to assist them and sufficient fodder for those animals, learning about mountain weather, and many other things. Creating an opportunity to learn more about the stars entailed embarking on an adventure that went beyond purely scientific challenges.

After Stock’s site testing, the American institution in charge of the mission, AURA or the Association of Universities for Research in Astronomy, decided to build a massive observatory in the semi-arid region of Coquimbo, Chile. AURA’s president was Donald Shane, by then director of the Lick Observatory. How much he knew about the Curtis Report remains somewhat of a mystery, but the Lick connection is certainly an exciting coincidence.

In the middle of that process, the Europeans changed their plans and left South Africa. Although Stock was on the American project, not theirs, they knew his site testing results were outstanding and decided to go to Chile. All this was not merely scientific, but intersected global and local politics.

It is interesting to note that in this first stage, neither the Americans nor the Europeans showed a concrete plan of what specifically they would do once they had their observatories running. They must have had a scientific plan, but official founding documents show interest in the unknown. That was the starting point of astronomy’s take-off in Chile, an activity that keeps growing on a local, national, and global scale.

Beyond the fascinating crossroads of science and politics, it is interesting to think about the dimension of producing scientific knowledge in these histories of astronomy. In recent decades, it has become clear that astronomy has had many “spillovers” in a variety of areas. Computing, data science, engineering, and even tourism are a few examples of how societies can embrace progress throughout astronomical development.6 However, in these initial stages of astronomy in Chile, these outcomes or were not known or addressed.

Astronomy in the early and mid twentieth century shows us how humans embraced astronomical tasks mainly because of their need to increase their knowledge of the unknown. Our protagonists’ efforts intersected in time and space—time because the endeavor at the turn of the century was linked to the technological plan of the 1960s, and space because this story brought together different nations of the world to metaphorically leave the planet and aim for more knowledge of the universe.

In June 1963, astronomers from the ESO (Europe) and AURA (United States) rode on horseback in the mountains of Chile’s Coquimbo Region in conjunction with their discussions about a possible joint venture. Source and further details: European Southern Observatory, https://www.eso.org/public/images/eso0912d/.

In both cases, astronomers had to be adventurers to even think about taking a step further in expanding the known universe. At the same time, scientific knowledge was not constrained by expected outcomes. On many occasions, the explanation lay simply in the “unknown.” Thus, it was uncertainty that created an opening for the development of new knowledge.

Contemporary Western societies tend to avoid uncertainty. The models for producing science embrace the unknown but at the same time reject it, even displace it for what could produce more results: speed, practicality, dependability. These episodes from the history of astronomy remind us of the relevance of adventure and the colossal potential of the unknown. Astronomy works at night, when we cannot be certain of what we see on earth. The darkness is precisely what enables us to look up and see starlight, many times unknown starlight.

Barbara Kirsi Silva is a professor of history at Universidad Alberto Hurtado, Santiago, Chile. She is author of Astronomy at the Turn of the Twentieth Century in Chile and the United States: Chasing Southern Stars (Palgrave Macmillan, 2019).

  1. William W. Campbell, “Will Determine Whether Solar System Speeds in Its Flight Through Space,” D.O. Mills Expedition, February 23, 1903, UA 36, ser. 04, box 8, folder 1, Lick Observatory Records, Special Collections, Mary Lea Shane Archives, University of California Santa Cruz. ↩︎
  2. Heber D. Curtis, “Astronomical Problems of the Southern Hemisphere,” Publications of the Astronomical Society of the Pacific 21, no. 129 (December 1909): 232. ↩︎
  3. Barbara K. Silva, Astronomy at the Turn of the Century in Chile and the United States: Chasing Southern Stars (New York: Palgrave Macmillan, 2019). ↩︎
  4. Heber D. Curtis, “Report on Astronomical Conditions in the Region About Copiapo,” D. O. Mills Expedition: Report on Site Survey Near Copiapo, April 17, 1909, UA 36, ser. 04, box 8, folder 12, Lick Observatory Records, Special Collections, Mary Lea Shane Archives, University of California Santa Cruz.  ↩︎
  5. European astronomers’ joint statement, Leiden, January 26, 1954, in Adriaan Blaauw, ESO’s Early History: The European Southern Observatory from Concept to Reality, (Munich: European Southern Observatory, 1991), 2 (translation by author). ↩︎
  6. Jose Guridi, Julio Perutze, and Sebastian Pfotenhauer, “Natural Laboratories as Policy Instruments for Technological Learning and Institutional Capacity Building: The Case of Chile’s Astronomy Cluster,” Research Policy 49, no.2 (2020), https://doi.org/10.1016/j.respol.2019.103899. ↩︎
Suggested Citation: Barbara Kirsi Silva, “What the History of Astronomy Can Teach Us about the Unknown,” History of Knowledge, October 14, 2021, https://historyofknowledge.net/2021/10/14/history-of-astronomy-and-the-unknown/.