In many ways, astronomers around the world can trace their scientific roots to Nicolaus Copernicus. Born on Feburary 19, 1473, Copernicus was a revolutionary astronomer and mathematician who turned Renaissance science on its head with the idea that the planets did not revolve around the Earth after all. With this radical notion, Copernicus set astronomy down a new path that transformed how scientists think about the universe.
Copernicus was born in modern-day Torun, Poland to a merchant family, but was cared for by his uncle, a priest, after his father died when Copernicus was just 10 years old. When he was 18, Copernicus travelled to Italy to study, at the time intending to eventually follow in his uncle’s footsteps and join the church. It was there that he was first introduced to astronomy, Nola Taylor Redd wrote for Space.com.
In the early 16th century, astronomy wasn’t really considered a science, but just one aspect of astrology, which was used as a means for predicting the future. People believed that astrology was critical for learned people like priests and doctors to know, and many universities taught astrology as a legitimate science. For them, astronomy was just a means for tracking the movements of the stars and planets to make more accurate predictions, Redd wrote.
At the time, most people subscribed to an Aristotelian model of the universe, which posited that the Earth sat at the center of existence and was surrounded by 55 concentric crystal spheres to which the stars and planets were attached, Deborah Byrd writes for EarthSky.org. However, there were mathematical flaws in this model, particularly when planets occasionally appeared to move backwards across the sky, an illusion called “apparent retrograde motion.”
As Redd wrote:
To account for it, the current model, based on the Greek astronomer and mathematician Ptolemy's view, incorporated a number of circles within circles — epicycles — inside of a planet's path. Some planets required as many as seven circles, creating a cumbersome model many felt was too complicated to have naturally occurred.
By 1514, Copernicus had given up becoming a cleric, instead devoting his time to astronomy, which he excelled at. But even as powerful leaders including the pope turned to Copernicus for astronomical advice, he was formulating a theory that would turn the Renaissance world on its head. That same year, he passed around handwritten pamphlets to his close friends that outlined his theories, including that it was the sun, not the Earth, that sat at the center of the universe, according to a BBC biography.
Though Copernicus’ theory had its flaws, it did solve the persistent problem of why planets sometimes appeared to orbit in reverse. However, the theory was so radical that he didn’t publish until 1543, when he was on his deathbed. Though it took nearly 100 years for his ideas to take hold, Copernicus’ book, De revolutionibus orbium coelestium (On the Revolutions of the Celestial Spheres), rocked the world of the Renaissance and sparked a scientific revolution carried on by successors like Johannes Kepler and Galileo Galilei (whose own birthday was earlier this week). By moving the Earth from the center of the universe, Copernicus helped transform astronomy from an addendum into the field of study it is today.