The Debate Between Harlow Shapley And Heber D. Curtiss

Although Harlow Shapley and Heber D. Curtis were the first astronomers to formally debate the scale of the universe in 1920 with their individual claims and findings on this highly contested topic, they were not the first or the last to postulate the various scientific theories of our universe. The “Great Debate” has been slightly misrepresented as an astronomical and scientific debate between only two astronomers when in actuality this debate and controversy was not a singular event in 1920, but a longstanding scientific effort as a result of a multitude of scholars trying to decipher and understand the scale of the universe. The history of events and discoveries that led to this debate and controversy span centuries and is an often overlooked

The explorations of the past and present must be addressed because they represent a clear and powerful usage of the scientific method. As stated by Virginia Trimble in The 1920 Shapley-Curtis Discussion: Background, Issues, and outcome, “Of course, a very large number of other astronomers contributed relevant data and ideas before, during, and after the epoch of the "great debate” (Trimble 7). This is an important and relevant discussion point to consider when analyzing the magnitude of the “Great Debate.” In Chapter 1 titled “The revival of the island universe theory” of Robert W. Smith’s book The Expanding Universe, Astronomy’s “Great Debate” 1900-1931, Smith provides necessary background information on the Shapley-Curtis debate that further displays the scientific processes and explorations of earlier generations that culminated in the infamous 1920 debate. For example, Smith outlines the theory that spiral nebulae were separate universes, which became known as the “island universe theory.” However, the foundations of the “island universe theory” were undermined by analyses of the distribution of nebulae in the sky during the late 1800s. Smith asserts that “During the 1880s two events occurred that seemed to have settled once and for all the issue of the existence of visible external galaxies.

This points directly to the importance of the scientific method and how Shapley was able to make such progress and observations because of past efforts. Shapley’s identification of the usefulness of Cepheid variables as distance indicators was a major point that he was correct about and this provided an immense contribution to the field of astronomy. On the other hand, Curtis was able to correctly identify that spiral nebulae are external galaxies and provided valid scientific evidence for the first time in history. As a result, his efforts exemplified that hypotheses become stronger and more valid once evidence is attained to support that observation made by a