Copernicus blazed a trail for early astronomers to follow

“As much as I can, I want to avoid offending good people,” Nicolaus Copernicus demurred when a correspondent urged him to publish his scientific work. As L.S. Fauber recounts in the sweeping and evocative “Heaven on Earth: How Copernicus, Brahe, Kepler, and Galileo Discovered the Modern World,” the Polish polymath ignited his revolution quietly. He set forth his principles of heliocentrism, placing the sun at the center of the universe, in a modest pamphlet he distributed to only a few fellow astronomers.

It’s difficult to overstate how radical Copernicus’s heliocentrism was in the 16th century, when it was taken for granted that the sun and planets orbited Earth. The notion was also heretical, since the Bible includes several references to an unmoving Earth. Still, and in spite of the reticence of the man who conceived it, the theory that the Earth revolves around the sun, and not vice versa, gradually and inevitably gained acceptance. One of Fauber’s primary aims in "Heaven on Earth" is to attribute the spread of that idea to three astronomers who came after Copernicus. Tycho Brahe, Johannes Kepler, and Galileo Galilei, Fauber demonstrates, built upon Copernicus’ efforts, and those of the others, to advance the field of astronomy in the face of daunting socio-political obstacles.

Brahe was born several years after Copernicus’s 1543 death, but Copernicus’ pamphlet eventually made its way to the Danish nobleman and astronomer, who further disseminated its ideas. Prussian King Frederick II gifted Brahe with a Danish island, and all of its inhabitants, to build an observatory and research center. As Fauber drily states, “He became the dean of astronomers, not by virtue of brilliance, but by hard work, constant reading, independent wealth, and the forced enslavement of a couple hundred peasants.”

From the island of Hven, Brahe, inspired by Copernicus, created the Tychonic system, which the author dubs “a chimerical beast”; it held that every planet but Earth orbits the sun, which itself orbits an unmoving Earth. Brahe’s more significant contribution than this deeply incorrect theory was his body of astronomical observations, painstakingly recorded over many years in 24 books.

After Brahe’s death, those books ended up in the hands of his onetime assistant, Johannes Kepler. Using Brahe’s observations, the German astronomer and mathematician developed his laws of planetary motion, his most important achievement, which posited that planets orbit the sun not in a circle, as Copernicus had hypothesized, but in an ellipse. In his youth, the devout Kepler had struggled to reconcile the Copernican system with Scripture. He ended up sidestepping the issue, essentially separating science and religion by making a flimsy distinction between “astronomical context” and “common usage.”

Kepler had a long correspondence with the Italian polymath Galileo Galilei, who, among his many accomplishments, advanced the field of astronomy beyond naked-eye observation by designing a telescope that led him to discover the rings of Saturn and the four moons of Jupiter. Galileo was also an adherent of the Copernican system, and he, more than his predecessors, got into trouble for promoting a theory that ran afoul of religious belief.

Like Copernicus, Galileo worried about what people thought of him. But he regarded popular disapproval with scorn, grousing, “It is necessary to give the Sun motion and Earth rest so as not to confuse the tiny brains of common people.” In 1616, he was admonished by the Roman Inquisition and forbidden from promoting heliocentrism. He was called back to Rome in 1633 to defend his writings and was found “suspect of heresy.” Some of his work was banned, and Galileo was sentenced to house arrest, where he remained until his death in 1642.

Fauber’s story ends there, but readers ought to continue on to the footnotes to get a full sense of how much the author, who translated many of the original sources, enjoys this material. For instance, after quoting a letter addressing an enemy of Galileo’s in colorful language that seems distinctly modern, Fauber admits of the words used, “I have had a lot of fun translating them, and they are not especially faithful except in tone.” Elsewhere the author confesses to “[indulging] a fair amount of pot-boiling” in describing the scandals surrounding a minor character. Fauber’s chronicling of these four astronomers’ scientific advances and their surrounding intrigues is lively and unfailingly fascinating, down to the footnotes.