In the past few years there has been a revival of people who believe the Earth is flat. NBA star Kyrie Irving and rapper B.o.B. are two of the more famous advocates for this infamous theory, and they’ve been widely mocked for holding such an outlandish idea.
But what if they are right?
They aren’t, of course—it should go without saying that there is an overwhelming amount of scientific evidence about the shape of our planet.
But there have been many other times in history when commonly accepted theories—ideas that amount to common sense—have been questioned. The people doing the questioning were mocked and dismissed, too. But it turns out they were right.
In the early 1500s, for example, it was Polish astronomer Nicolaus Copernicus proposing outlandish ideas about the Earth. He developed the theory of heliocentrism, claiming that the Earth wasn’t the center of the universe. The sun was.
That idea went against all popular understandings of the planets. It quite literally reordered the universe. In fact, it was so wild that Copernicus waited forty years before he published his ideas in full. And he only did so after a brilliant young mathematician, Georg Rheticus, showed up on his doorstep uninvited and convinced him to.
In took more than one hundred years, but Copernicus’s ideas went from a laughable theory, to a manuscript passed around among scientists, to the basis for our understanding of the solar system. And that story contains important lessons for how science works.
Copernicus was born in 1473 in what is now Poland, and he spent much of his teens and early twenties studying at various universities around Europe. One of those stops was in Bologna, Italy, where he worked closely with an astronomer, making observations of the stars and planets to create charts and tables of their movement.
At the time, astronomy had a very different role than it does today. It wasn’t just the science of how planets move—it was deeply connected with astrology and horoscopes, which were used to make predictions about future events. According to the Encyclopedia Britannica,
In Copernicus’s period, astrology and astronomy were considered subdivisions of a common subject called the “science of the stars,” whose main aim was to provide a description of the arrangement of the heavens as well as the theoretical tools and tables of motions that would permit accurate construction of horoscopes and annual prognostications. At this time the terms astrologer, astronomer, and mathematician were virtually interchangeable; they generally denoted anyone who studied the heavens using mathematical techniques.
But intellectuals were already discovering issues with their understanding of the universe. Based on planetary models that were developed centuries earlier by Aristotle and Ptolemy, scholars assumed that the Earth was stationary while the sun and other planets revolved around it. Yet, those models didn’t quite work.
The models said the planets should be in one place, but when astronomers like Copernicus observed their movements across the sky, they were someplace else. Astrologists couldn’t even agree on what order the planets were in. All across Europe, scholars were debating planetary theory, trying to resolve the contradictions they kept running into.
“The math didn’t hold up,” Dava Sobel, author of A More Perfect Heaven: How Copernicus Revolutionized the Cosmos, explains to TIP. “Scholars and mathematicians were working with a model that is not based on reality.”
Publishing the work
But they didn’t have a better model yet, because Copernicus hadn’t written it.
Between 1508 and 1514, Copernicus did write a short manuscript known as the Commentariolus. It briefly laid out his theories. But he only distributed a few copies to his friends and fellow astronomers—he never published it.
He was busy working as an administrator for his church. In his spare time, he made more detailed astronomical observations, collecting data he would eventually use to justify heliocentrism.
“He seems to have decided against publication out of fear that he would be laughed at,” Sobel says. Lucky for us, he was convinced otherwise.
“Out of nowhere, this young genius arrives at his door. Copernicus at this point is in his late sixties, and this guy is twenty-five years old. He tries to convince him to publish, and Copernicus does as the visitor asks.”
That visitor was Rheticus. He was a talented astronomer in his own right who heard about Copernicus’s Commentariolus and was intrigued. There are no records of his meetings with Copernicus, so it’s unclear how he convinced the now legendary scholar to risk public ridicule. But somehow he did it. Then, he helped Copernicus follow through, writing one short work with him, then taking Copernicus’s masterpiece, De revolutionibus orbium coelestium libri vi, and ensuring its publication.
Copernicus died shortly after his theory was published. In fact, the common, though potentially mythical story, is that he had a stroke, woke up holding his newly printed work, and then died soon after. But the story of his impact doesn’t end with publication.
The rest of the story is about how his ideas became mainstream—and that is a tale much longer than one man’s life. It’s the tale of how science works.
From normal science to revolution
In his influential 1962 book The Structure of Scientific Revolutions, the philosopher of science Thomas Kuhn argued that science alternates between periods of progress and upheaval.
He calls the periods of progress “normal science.” During those times, science is “firmly based upon one or more past scientific achievements” which “define the legitimate problems and methods of a research field.”
Before Copernicus, that was the role played by Ptolemy: his work defined how scholars did astronomy. They used Ptolemaic models, found solutions to problems Ptolemy discovered, and gathered the kind of data Ptolemy thought was important. Kuhn uses the word paradigm to define that kind of influence: Ptolemy provided a paradigm for astronomy, because he defined the tradition scientists inherited.
Astronomers had plenty of problems to solve—like which order the planets were in, when future eclipses would occur, and so on—but they did so by using Ptolemy as a guide.
But in some cases, science doesn’t proceed normally. A problem arises. There is some anomaly that throws the whole paradigm into question, some issues that can’t be explained by the existing paradigm. That’s what happened in Copernicus’s time.
“By the early sixteenth century,” Kuhn wrote, “an increasing number of Europe’s best astronomers were recognizing that the astronomical paradigm was failing in application to its own traditional problems.”
At that point, normal science stops working and there is an “exploration of the area of the anomaly.” Someone like Copernicus gathers the data, observes the planets, and makes the charts. Eventually, “the anomalous has become the expected.” In other words, there’s a “paradigm shift,” and a new paradigm explains the problem that was previously unexplainable.
That’s what Copernicus did. His theory went completely against the dominant paradigm. But it explained the problems Ptolemaic astronomy couldn’t.
“When he moved the sun, there was a reason for [things like] the orbital speed of the planets. It gave a logical order to the whole system,” Sobel says.
Changing your viewpoint
From 2018, it’s easy to forget how difficult things must have been for Copernicus. Of course he was proven right, you might think, the Earth is clearly not the center of the universe.
“The story seems self-evident from a modern perspective,” Sobel says. “A lot of people think people were stupid in the 1500s. But we know the Earth goes around the sun because we were told. Figuring it out was not a simple matter.”
To move from one paradigm to another, scientists must learn “to see nature in a different way,” Kuhn says. It’s a fundamental shift in how scientists are doing science—what questions they ask, what methods they use, and what theories they accept.
Even though many astronomers knew existing theories of a stationary Earth weren’t working, creating a whole new model went against all public opinion, all scholarly studies, and all of the most powerful institutions in the world, including the Catholic Church. To hold firm to your beliefs in spite of that is nothing short of extraordinary. How in the world did Copernicus do it?
“I think he was convinced by his own evidence,” Sobel says.
She also notes that it may happen in our time, too, with current problems in science like dark matter. “Maybe there are problems facing students today that seem self-evident, but in fact aren’t. I mean, aren’t we now facing the likelihood that everything we can see in the universe is just a tiny fraction of what actually exists?”
Kuhn agrees, too. His philosophy of science holds that scientific revolutions will continue to come up, and that some of our current paradigms will be replaced. We only need the scientists to create the new ones.