1920: Harvard Astronomy in the Aftermath of WW1

*With this blog series, we also hope to instigate meaningful conversations about our institution’s history. We therefore invite you to comment on our posts and share your thoughts with us.

President Warren G. Harding and First Lady Florence Hardin

Jazz Age America, also known as the “Roaring Twenties” or the “Golden Age Twenties” in Europe, was born from the post-war economic prosperity that followed the 1919 Armistice. The 19th Amendment became law on August 18, 1920, representing the largest expansion of voting rights in American history since the Revolution. With the inclusion of women in the election that year, voter turnout increased nearly 25% over the previous two elections, and Republican Warren G. Harding won in a landslide victory. The first commercially-licensed radio station broadcast the results live. In 1920, the Paris Peace Conference, which negotiated the end of the ‘Great War,’ culminated in the founding of the League of Nations, an international intergovernmental organization designed to maintain peaceful relations between wartime enemies. President Woodrow Wilson received the Nobel Peace Prize for his part in establishing the League, but when the decision to join passed to his successor after the election, Harding withheld American participation.

Seattle Police Officers in Masks. Dec. 1918.

Worldwide, 1920 marked the end of the third (and final) ‘Spanish Flu’ outbreak. The cramped and water-logged trenches of World War One provided a fertile breeding ground for the deadly strain of influenza, though the disease likely earned its name because Spain was neutral in the war, and therefore wasn’t censoring their reports of early fatalities. Between 1918 and 1920, an estimated third of the world’s population contracted the disease. In all likelihood, the war both aided in the spread of the virus, as infected soldiers returned home to all corners of the globe, and the virus similarly impacted the course of the war because it limited the support capabilities of the home front. Local authorities in Europe and the United States purposefully minimized quantitative reports regarding the numbers of people affected or dead during wartime to avoid lowing public moral, which contributed to its later minimization in the historical record. The war killed 20 million people, while the virus killed upwards of 50 million more.

In 1920, the international scientific community was similarly reeling from the events of the previous decade. The same political questions loomed large in academia. How did individuals recover from personal and collective human loss? What manner of reconciliation was possible between wartime enemies? What would it look like to move forward?

Henry Moseley. c. 1914.

Unlike later twentieth-century wars, scientists in the First World War fought in almost equal measure from their laboratories and on the battlefield. Henry Mosely was an English physicist whose pre-war research in x-ray spectra proved the association between an element’s “atomic number” and its place on the periodic table and provided the first experimental evidence in support of the Bohr Model. When the war began, he left his job at the University of Oxford to volunteer with the Royal Engineers of the British Army. Mosely joined a force of soldiers invading Turkey at Gallipoli, where he was shot and killed. He was twenty-seven when he died. Isaac Asimov, born in 1920, later wrote that Mosely’s death, in light of what he could have accomplished, “might well have been the most costly single death of the War to mankind generally.” The resulting backlash from the international scientific community after Moseley’s death led to significant changes in the relationship between military action and civilian scientists, which had a profound impact on the later wars to come.

Edwin Hubble. Military ID.

The challenge wasn’t only that intelligent, promising young men died, but that men who’d left their civilian appointments to aid in the war efforts were returning home. World War One was the source, at least in part, of the “life-long coolness” between astronomers Edwin Hubble and Harlow Shapley. Hubble voluntarily enlisted in 1917 as soon as the United States entered the war, after rushing to complete his dissertation and deferring an offered position at the Mount Wilson Observatory. Shapley remained at Mount Wilson through the duration of the war, and spent his time working on a project Hubble had planned to pursue upon his expected return. Observatories all over the world faced significant administrative challenges in the aftermath of war, marked by interrupted or unorganized research, funding crises, and associated staffing changes. This heightened the importance of international cooperation in astronomical research at a time when foreign affairs were still somewhat volatile.

On July 28, 1919, a Constitutive Assembly of the International Research Council founded the International Astronomical Union at a post-war meeting in Brussels, Belgium. The IAU, established under the Treaty of Versailles explicitly abolished all international astronomical organizations from the pre-war period while simultaneously withholding membership from the defeated countries, most notably at the time, Germany. Over the course of the following year, conversation abounded throughout the scientific community about the extent of future scholarly cooperation between former enemy countries. These conversations echoed contemporary political provisions in the Treaty of Versailles, which imposed infamously harsh penalties against the German state. In September 1920, a report published in Science magazine suggested that The Royal Society of London was considering a new provision that would expel all of its members from enemy nations, a sentiment which was growing in popularity at the time throughout Europe. Unlike previous wars, scientists were highly involved and increasingly visible on either side of the war, which resulted in significant tension between scholars in the post-war period.

While observatories in the United States suffered similar challenges, America’s delayed entry into the war and its geographical distance from the fighting, meant that the major responsibility for advancing science in the western world fell largely to the United States during the war and in its immediate aftermath. By 1920, American astronomers had an almost unprecedented influence on the international astronomical community because the wartime losses in Europe were so severe. The impact of World War One was far-reaching, as were the decisions made in its aftermath. International scientific cooperation was a topic of debate, and was not equally pursued in the post-war period across all disciplines.

Long before the founding of the IAU, Harvard College Observatory Director Edward Pickering put forth considerable effort to maintain international relationships between astronomers. In a letter written in response to the United States’ declaration of war, Pickering admitted, “I felt we could maintain our position as neutrals and might help more than as combatants. My feeling has been that nothing should disturb our relations to science.” Pickering ultimately aided the war effort through his work on submarine detection, and a device he invented called the Pickering Polaris range finder was among the few contemporary instruments put into production by the War Department. Still, cooperation and eventually reconciliation was his clearest aim. In a 1918 letter to George Ellery Hale, Pickering commented on the Interallied Research Council, a cooperative wartime organization which limited its membership among the Allied Powers (including Great Britain, France, Russian, and the United States). He complimented the council’s position in regard to the “successful prosecution of war,” but to his mind:

“The advancement of pure science internationally is a very different question. This is especially the case with modern astronomy, which stands on a different basis from almost every other Science. It is purely impersonal, seeking after truth, independently of individuals or nations. Every consideration should give way to the fulfilment of this object. No ordinary punishment is adequate for those responsible for barbarities contrary to the laws of nations and humanity, yet we ought not to ignore the work of those who, laboring quietly in their observatories, have done their best to extend our knowledge in these terrible times. I hope, therefore, that in Astronomy no definite action in this matter will be taken during war times, until we know the attitude of those whom we once admired and respected.”

Edward Pickering. c. 1880s.

In January 1919, Pickering wrote in a letter to Swedish-Danish astronomer Elis Strömgren, “I want to reestablish relations with such of my good friends among the German astronomers as were not in any way responsible for what we consider deeds contrary to the laws of war… I do not approve of the plan of establishing international societies in which scientific man of the central and neutral nations are not included, at least in the case of such subjects as have no relation to war.” When Pickering learned that the Royal Society was considering expelling its German members, he further declared his protest in a letter to the Secretary Arthur Schuster. German reparations outlined in the Treaty of Versailles were severe, to the extent that later scholars would link the negotiated end to World War One with the eventual beginning of World War Two. In the international political climate, Pickering’s stance was controversial.

Edward Pickering died in February 1919, which meant that the responsibility for navigating Harvard’s response to the questions of post-war international cooperation would fall to his successor. 1920 looms large in the history of astronomy for the ‘Great Debate’ between Heber Curtis and Harlow Shapley on “The Distance Scale of the Universe.” Shortly after the famed debate, Shapley was offered the Directorship of the Harvard College Observatory, and formally began his tenure the following year. As Director, Shapley encouraged visits from foreign astronomers, attracted international students for the new graduate program, and as tensions escalated overseas in the years proceeding World War Two, he arranged temporary appointments for refugee scholars. Harvard’s amble resources, in comparison with smaller observatories, meant that they were better equipped to handles scholars with diverse linguistic backgrounds. Shapley’s work toward international cooperation was so significant, he was later credited as “the man who put the S in UNESCO.” Other American and European observatories similarly rejected the contemporary political climate and led comparable initiatives, but few rivaled the resources, reputation, and faculty-support found at Harvard.

*This blog addresses the aftermath of WW1 in general terms among astronomers in the United States and Europe, but does not meaningfully discuss contemporary scientific history beyond the western world. Below are a few introductory sources which expand upon events in astronomy elsewhere in the world in the 1920s:

Dubow, S. (2018). 200 Years of Astronomy in South Africa: From the Royal Observatory to the ‘Big Bang’ of the Square Kilometre Array. Journal of Southern African Studies, 45(4), 663-687.

Nakamura, T., & Orchiston, W. (2017). The Emergence of Astrophysics in Asia: Opening a New Window on the Universe (1st ed. 2017. ed., Historical & Cultural Astronomy). Cham: Springer International Publishing : Imprint: Springer.


Asimov, Isaac (1982). “1121. MOSELEY, Henry Gwyn-Jeffreys”. Asimov’s Biographical Encyclopedia of Science and Technology (2nd revised ed.). New York etc.: Doubleday. pp. 713–714.

Elliott, Clark. A. Science at Harvard University: Historical perspectives (M. Rossiter, Ed.). Bethlehem, PA: Lehigh Univ. Press, 1992.

Erkoreka, Anton. “Origins of the Spanish Influenza pandemic (1918-1920) and its relation to the First World War.” Journal of molecular and genetic medicine : an international journal of biomedical research vol. 3,2 190-4. 30 Nov. 2009, doi:10.4172/1747-0862.1000033

Jones, Bessie Zaban. Boyd, Lyle Gifford. Harvard College Observatory: The First Four Directorships, 1839-1919. Harvard University Press, 1971.

Trimble, V. (1995). THE 1920 SHAPLEY-CURTIS DISCUSSION: BACKGROUND, ISSUES, AND OUTCOME. Retrieved July 16, 2020, from https://apod.nasa.gov/diamond_jubilee/papers/trimble.html