The Evolution of Astronomy: from Myth to Math
On charting the heavens and the formation of modern science
I think it would be difficult if not impossible to find a person who has never looked up at the night sky in wonder. To find someone who has never stared at the moon with a weird human longing for a different past or more exciting future, someone who never let their mind wander towards the seldom understood emotions of grief, love, and nostalgia. In-fact, so many of us took respite in the foreign that we gathered the figments of our imaginations and drew them in flickering specks of light, calling them constellations or a “set of stars” that might be hundreds of thousands of miles away from each other, only brought together by our fascination for the heavens.
For a long time that is what we called space - the heavens, an abode for the worthy and supernatural, a residence for the gods. Maybe that’s why, even today, when we lose a loved one, we immortalize them in the night sky and they live on in the stars that have carried the souls of thousands across centuries, people we can miss but not feel. And as space became a vessel for both mortality and myth, we began creating stories to explain a lifetime of shared phenomenon. This led to the introduction of the first theories about the universe and kicked off decades of debate and political strife.
It all began when the institutions that held our society together realized that the idea of time and its passage was quintessential to a functioning society. Each culture came up with its own method, all of them revolving around the delicate balance of the movements of the sun and the moon, but the one we will be discussing led directly to the Gregorian calendar that clocks all our official birthdays.
The leading theory stretching all the way back to the time of Aristotle was that Earth was a perfect sphere at the center of the universe. Back then the planet was composed of four primordial elements, fire, water, air, and earth, and everything in the sky and beyond was composed of and held by aether (which also forms the root of the word ethereal or other-worldly). Around the 2nd century AD, a Roman astronomer called Claudius Ptolemy formalized this geocentric model. In a time well before telescopes, he took his observations of uneven seasons and the eastward motion of constellations to come up with theories that helped explain the many discrepancies of the universe.
Although false in hindsight, those explanations were no small feat. As J. L. Heilbron put it in his (impeccably written) book “When God made everything according to measure and number, He chose hard ones for astronomy.” Nothing is perfectly divisible and it took us hundreds of years to come up with a functional (if not good) way to deal with the excess remainder.
This idea of human significance in the universe sat well with the most powerful eurocentric coalition at the time - The Catholic Church. After all, creationism conflates the advent of the universe with that of human life, and if the Earth wasn’t centrally important and the heavens were more than just heaven, it might create a crisis of faith so deep that the existing hierarchies would collapse.
That being said, it is surprising to learn the church acted as a patron for many scientists who might otherwise not set the foundational basis we use today- the perceived rift between science and religion is fairly recent. The general understanding of science was that it was a tool to better understand God’s creation and many scientists including Copernicus (who is a canon and established heliocentrism) and Galileo were staunchly religious. Even Newton spent the final thirty years of his life deeply committed to theological study.
Which brings us back to time and its inextricable link with astronomy. Dates and minutes, it turns out, are crucial for ritual celebration - after all it would be odd if Christmas didn’t fall on the same day every year. These rituals were not only marquees of religious devotion but also offered a much needed break for people which made it important to have the dates match both theologically and with the solstices that marked harvest seasons.
It is much easier now that we know orbits are elliptical and solar and lunar cycles are not whole numbers, but back then, the date of Easter was set using the Jewish lunar calendar which used an additional month that arbitrarily accounted for any mathematical mismatch. Catholic officials would then use that calendar that was created by the eye of a high-ranking Rabbi, and announce when Easter fell. However, as the religion spread, this was no longer efficient or feasible - enter a series of church appointed astronomers who grappled with this issue.
Ultimately, this problem culminated in the heliocentric system, one that was not accepted when considering divinity but was used arithmetically and all was more or less fine for a few years. However, underneath the broader societal surface, rift and discourse were rife in the more affluent intellectual circles that had both the literacy to read and time to contemplate Copernican ideals. The publication of de revolutionibus orbium coelestium (On the Revolution of the Heavenly Spheres) had unknowingly kicked off what we now call the Scientific Revolution - a time period that can best be described as a series of discrete events that cumulatively redefined human relationship with the natural world.
There were lots of prominent people working in this period - Francis Bacon, Rene Descartes, Isaac Newton, Tycho Brahe, and Johannes Keppler to name a few. But for the purpose of keeping this essay within the bounds of reasonable length, we will be discussing the subject of many awe-striking stories, Galileo Galilei.
Besides discovering the four moons of Jupiter, Galileo was a staunch proponent of the heliocentric theory and embodied the modern-day paradox of religion and science in one being. In my opinion, it is through the remarkable course of events catalyzed by his life that the first truly deep and permanent fissures appear in the separation of scholastics and divinity.
In a time of rising Protestantism that the Catholic Church attempted to counter using the Inquisition of 1616, Galileo unknowingly presented another thorn in their side. He was a revered lecturer, prominent inventor, and most importantly wrote books in both Latin and Italian which made his work accessible and thus dangerous to the institutions of power.
In the wake of the Inquisition, Copernican ideology was banned and Galileo stopped teaching till he felt it was safe to return when the church was helmed by an old friend of his. He did, however, continue writing books that noted his observations of normality in the heavens, and smuggled out a print of his early ideas on inertia to the more lax protestant regions.
During his hiatus from lecturing, Galileo worked under the patronage of the Medici family (in whose honor he named the Medicean stars) and published open letters to them that allowed him to leverage their authority to take on the Catholic Church. In one addressed to Grand Duchess Christina, he effectively walks the line between faith and form by using scripture from St. Augustine to make a case for humanity’s moral duty to know more (through the lens of the heliocentric system). His main arguments center around the claim that physical truth and scripture cannot be different and that science can help better understand the text. He also goes after critics by stating that they are not interpreting the Bible correctly with the final break in his religious relationships arising when he underscores a need to have separate groups of people studying divinity and science.
The ideas in his letter were buried into collective memory not only through his book arguing for Copernicus but also via Galileo’s ultimate trial and condemnation. The event helped introduce the notion that scientific progress was dangerous in Catholic controlled areas, a belief that permeated to all of religion eventually. Yet for all that he said and did, Galileo never once contemplated leaving the church or the land governed by the Vatican. Looking back, his devotion and piety to a church that stood against him is difficult to understand — maybe when it comes to matters of faith, the horizon blurs just a little bit more.
But if you do find yourself greeted with a clear night sky today, gaze up for me. And whether you look with clinical precision or childlike wonder, I hope your mind wanders to the thousands who have mapped the heavens the next time you wish on a shooting star.
Reference list:
Heilbron, J. L. The Sun in the Church: Cathedrals as Solar Observations. Cambridge: Harvard University Press, 1999.
Galilei, Galileo, "Letter to the Grand Duchess Christina of Tuscany, 1615" (2013). Instructional Resources. 97.
https://digitalcommons.bard.edu/sr-instruct/97Sobel, Dava. Galileo's Daughter: A Historical Memoir of Science, Faith, and Love. New York: Walker & Co., 1999.
French, Jacques Louis David. “Jacques Louis David: The Death of Socrates.” The Metropolitan Museum of Art, January 1, 1787. https://www.metmuseum.org/art/collection/search/436105.