Jim Fleming: The debate over the origins of the universe has riled up plenty of people, but to find a truly earth shattering controversy in the world of physics, you'd have to go back hundreds of years to the revolutionary idea that the Sun, not the Earth, is the center of our solar system. Of course, that was the remarkable discovery of Copernicus, who's the subject of Dava Sobel's book A More Perfect Heaven. Sobel says, “It's hard to appreciate how radical his idea once was since we all now take it completely for granted.”
Dava Sobel: School children today know it. The rest of us know it. Only because we've been told. It's not at all obvious that the earth is in motion. It certainly doesn't feel as though it's moving, does it?
Fleming: No. No and I guess that what you then move immediately onto is the realization that the whole world was different. The world into which Copernicus was born was, in a lot of ways, not at all like the world in which we live. Was it?
Sobel: Not at all and he was involved in so many things. He was a cleric in the church, but then he was also a medical doctor. His bishop's personal physician. And because of the Knights of the Teutonic Order who lived all around the area of Poland where he grew up and then spent his adulthood, he was actually engaged in active warfare from time to time. And then there was great religious upheaval. It was during Copernicus' time that Martin Luther broke from the Catholic Church and a great wave of conversion spread over Europe. Not to mention, Columbus' travels while Copernicus was a college student.
Fleming: The whole world was changing, in other words. And in the midst of all of this, Copernicus is, of course, contemplating a change in the way people will think about not just the city or village where they live or even the country in which they live, but the planet on which they live. We see that again as revolutionary. Did he see it as big a change as we do?
Sobel: Yes, indeed. He knew it was a monumental change and that was part of what gave him his anxiety. He knew it was philosophically difficult. That it seemed to go against common sense and people might ridicule him. And, of course, he feared a religious backlash.
Fleming: What was different about Copernicus that caused him to see the world differently?
Sobel: No one really knows that. But when he saw how putting the sun at the center would organize the planets in order of their speed, he knew he had hit on something powerfully important. And even though there was an ancient Greek mathematician, Aristarchus, who had considered putting the sun at the center, Copernicus actually didn't know that. So he was alone and felt alone. And he was frightened of what would happen if he publicized his idea.
Fleming: Well this brings us back to Rheticus, who's at the center of your story. This young Lutheran man who braved a trip into Catholic territory where he was forbidden.
Sobel: Yes. Their meeting was so important, because it united these two people. One old, one young, different religions, but they came together over that idea. And then it was that book that really did change the world, turn the universe inside out, bring Galileo to trial, wind up on the index of prohibited books.
Fleming: You talk about the things we don't know about Copernicus. Do we know more about Rheticus?
Sobel: We know some, maybe a little bit more about Rheticus, because he was a little bit more expansive, wrote a few more letters, but no one made any kind of record of their discussion with each other.
Fleming: But it must have been extraordinary, because we start with the fact that Rheticus came into a place where he knew he wasn't wanted and then persuaded a man who had been afraid his whole life to publish this book.
Fleming: To change his mind.
Sobel: He convinced Copernicus to do what he had avoided doing for a lifetime. That must have been some conversation.
Fleming: It must have been. Now, of course, what he published is not the Copernican universe that we see today. It was an early version of it.
Sobel: Well, we no longer think that the sun is the center of the universe, but only the center of the solar system.
Fleming: It took the work of Tycho Brahe and Johannes Kepler to expand upon the Copernican theory?
Sobel: Indeed. Indeed. Tycho brought many more and better observations to bear, yet he couldn't accept Copernicus' theory. And one of the reasons he couldn't accept it, aside from the fact that he thought motion of the earth was a ridiculous idea, but he couldn't accept the expanded cosmos. For Copernicus' idea to be correct, the stars had to be much farther away than people had thought and Tycho couldn't believe that either. And so he clung to the idea of the earth at the center. He put all the other planets in orbit around the sun and had that whole whirligig moving around the earth. It was Kepler who worked as Tycho's assistant for a while and then used his much improved data to see the reality of the elliptical orbits.
Fleming: It's interesting isn't it to see each step in the emotional acceptance of the scientific change? Because so much of it is rooted in people saying, “Well that can't be true.”
Sobel: Exactly. And of course we still do that today.
Fleming: What was the reaction of the world at large when this book was published?
Sobel: The world that reacted to Copernicus was an educated world. His book came into print with an anonymous preface that he didn't know about that told people not to take the idea too seriously. That it was just another way of thinking about doing the calculations. So he was protected from any outright criticism for a while. It was only when Galileo's discoveries began to provide a body of evidence for what Copernicus had suggested and when Galileo began speaking out in favor of Copernicus and writing in Italian as opposed to Latin, the language of scholars, because Galileo was looking for a way to communicate with an intelligent layman who'd not been able to afford a university education, it was at that point that the church took issue with Copernicus.
Fleming: Not during his lifetime basically, but later.
Sobel: No. He died as soon as the book was finished. So he never knew what the response to it was. But the big question in the way people look at this issue is whether humanity was demoted from a place of central importance. I think at the time the center was not considered an exalted place. It was merely different. Profoundly different from everything else. So all the heavenly bodies were thought to be made of a perfect, everlasting, unchanging substance. Whereas things on the Earth were made of earth and water and air and fire. And there was lots of change and there was death and decay. So it wasn't the best place in the universe. That was reserved for the heavenly bodies and all the way out beyond the stars, God and the angels. And the bigger problem for Copernicus was taking the earth and making it a wandering star like the other planets. Making this pit of decay a celestial body. And taking the sun out of the heavens and putting it in the center. This was a philosophical conflict of great depth.
Fleming: That's science writer Dava Sobel. Her book is called A More Perfect Heaven: How Copernicus Revolutionized the Cosmos.