In This Chapter
• The changing view of the world
• Copernicus: the center of controversy
• The mounting evidence against Ptolemy
• Newton puts it all together
• Dogmatic religion and science don’t mix
• The making of the scientific method
The sixteenth and seventeenth centuries proved as unsettling for science and philosophy as for religion. Just as Luther, Calvin, and others led a theological revolution that shook the very foundations of Christendom, a number of scientists beginning in the sixteenth century led a revolution of sorts in science that challenged everything humans thought they knew about the world and universe around them. The work of the scientists made waves not just in the academic and scientific worlds but in the world of religion, too.
Each scientist who contributed to the body of knowledge built upon the work of his predecessors. By the turn of the eighteenth century, ancient scientific flaws had been revealed, new discoveries had been made, and the approach to science had been changed forever. Also like the revolution in religion, the revolution in science initially was met with much skepticism and loud outcries from many who refused to accept that what they had always believed may have been inaccurate. The Scientific Revolution was revolutionary only in the sense that an old way of doing things was replaced by a new way; the term “revolution” in no way implies that the changes took place quickly.
Historians often refer to the post-Scientific Revolution concept of the universe as a “new worldview.” This new outlook involved accepting new ideas and rejecting, or at least being open to skepticism about, old ideas. For many academicians, “out with the old and in with the new” was uncomfortable and disconcerting.
The new worldview eventually extended to many areas of science but it began in the field of astronomy, which experienced a resurgence following the Renaissance. Not only had the Renaissance fostered curiosity and discovery, it had encouraged the study of classical texts. Among the ancient texts dusted off for research were those of classical philosophers and astronomers like Aristotle and Ptolemy. The work of such philosophers and astronomers made up the core of what Europeans believed about the universe for more than a millennium.
Would You Believe?
Governments patronized scientists the way that rich individuals and the Church patronized the arts.
The Renaissance fascination with classical texts wasn’t the only factor in the renewed interest in astronomy. The fifteenth and sixteenth century emphasis on navigation, cartography, and exploration necessitated new and better techniques for viewing and mapping the stars. These factors, combined with the intellectual curiosity that grew out of the universities of the Middle Ages, made the conditions prime for a revolution in scientific thought.
The “Old“ Worldview
Prior to the Scientific Revolution, the scientific and religious communities placed a great deal of faith in the work of the classical minds of Aristotle and Ptolemy, who studied the heavens, speculated about the night sky, and made calculations.
Their observations seemed to indicate that the heavenly bodies they observed in the sky orbited the Earth in circular patterns. They calculated the orbits of the stars and the sun with no real problem, but the orbit of the planets gave them fits. Rather than following circular orbits, the planets seemed to be all over the place. Ptolemy explained this by saying that the planets traveled in epicycles within their orbits around the Earth. The belief that the heavenly bodies orbited around the Earth was known as the geocentric view of the universe, that the Earth is the center.
Define Your Terms
An epicycle is a smaller orbit within a larger orbit.
Aristotle compounded the confusion by maintaining that the heavens and the heavenly bodies were composed of different matter than the Earth. The combination of Aristotle and Ptolemy’s ideas produced the concept known as the Ptolemaic universe. The Ptolemaic universe consisted of a series of crystal spheres containing the orbits of the sun, moon, stars and planets. The Ptolemaic universe placed the stationary Earth in the center of the crystal spheres. Beyond the crystal spheres was heaven, where God and the angels resided.
This suited the Church just fine. According to the scheme of the Ptolemaic universe, the universe was finite and heaven and God were in an absolute location. This made everyone feel secure about things that could not be seen. The spheres of the old worldview, though, were soon to be shattered.
The Copernican Hypothesis
Nicholas Copernicus (1473-1543) was a brilliant scholar with a background in church law, math, medicine, and astronomy. He studied astronomy in Poland after receiving a clerical position.
Copernicus believed that Ptolemy’s system was flawed. He didn’t necessarily doubt the idea about the spheres or about perfectly circular orbits, but he wasn’t sold on Ptolemy’s rules explaining the orbits of the heavenly bodies. Copernicus was interested in an old theory that dated back to the ancient Greeks and placed heavenly bodies in orbit around the sun rather than around the Earth. Copernicus worked with this theory for more than 20 years.
Afraid that he would be the laughingstock of the world of astronomy, Copernicus did not publish his work, On the Revolutions of Heavenly Bodies, until 1543. A devout Catholic, he dedicated the work to the pope. Copernicus did not declare the heliocentric theory that the sun is the center of the universe to be truth in his book, but rather offered the theory for speculation and for mathematical consideration.
The heliocentric theory challenged a number of ideas besides just the geocentric nature of the universe. If Copernicus’s theory were correct, the size of the universe would actually be exponentially larger than under the Ptolemaic system. The stars in the Copernican theory stayed still while the Earth moved, a huge departure from Ptolemy. One of the biggest points of contention arose over the position and makeup of the Earth. According to the old worldview, the Earth was the center of the universe, and everything else, made of different matter, revolved around it. The Copernican theory took the Earth out of the center of the universe and made it just like any other planet flying through space. It meant that the heavenly bodies were made of the same matter as the Earth. It reduced the importance of Earth in the universe God created. It also took heaven off the map.
Copernicus’s theory was revolutionary only in that it made everyone stop and think a little differently. Copernicus proved little except that the geocentric universe didn’t exist. After all, the sun isn’t the center of the universe. It would be up to the astronomers who followed to take Copernicus’s ideas and prove them. Copernicus died shortly after he saw the first copy of his published book in 1543.
Brahe, Kepler, and Galileo
One of Europe’s leading astronomers, a Dane named Tycho Brahe (1546-1601), put himself on the map when he studied a new star that appeared in the night sky in 1572. After becoming renowned, Brahe reaped the rewards of his fame. The Danish government financed a huge observatory for Brahe. Since Brahe believed that the planets revolved around the sun and the sun and planets together revolved around the Earth, his theories weren’t his greatest contribution to science. But Brahe studied the heavens, both with the naked eye and with an expensive telescope funded by the Danish government, for more than 20 years, amassing more data than he could ever synthesize. The amazingly accurate data that he collected was to be Brahe’s legacy.
Would You Believe?
Tycho Brahe lost part of his nose in a duel and replaced the missing part with an alloyed metal made of gold and silver.
Brahe’s apprentice, Johannes Kepler (1571-1630), kept the data collected by Brahe and used them to work on Copernicus’s theory. For 10 years Kepler applied Brahe’s work to Copernican thought. A gifted mathematician, Kepler believed the key to understanding the universe was to be found in mathematics. He believed that a mathematical relationship existed between all the heavenly bodies in the universe.
Finally, Kepler produced three fundamental laws of planetary motion. First, Kepler proved that the planets traveled in elliptical orbits and not in circular orbits with epicycles. Second, Kepler showed that a planet’s speed increases as it gets closer to the sun and then slows down as it moves farther away from the sun. Third, Kepler demonstrated a direct relationship between a planet’s distance from the sun and the time it takes that planet to orbit the sun. Kepler’s laws proved what Copernicus speculated: the Ptolemaic system was wrong.
As a Matter of Fact
Johannes Kepler belonged to a Lutheran family but he disagreed with Luther's stance on the Eucharist. As a result, the Lutheran Church refused him the sacraments. In spite of the fact that he could not receive the sacraments within the Lutheran Church, Kepler refused to convert to Catholicism. On another interesting note, near the beginning of the Thirty Years' War, Kepler defended his mother against charges of heresy and witchcraft.
Would You Believe?
Galileo conducted his motion experiments by rolling balls down grooved pieces of wood and not by dropping the balls from atop the Leaning Tower of Pisa. These experiments resulted in the law of inertia.
About the same time Kepler pored through Brahe’s data, Galileo Galilei (1564-1642) explored ideas about motion. Galileo, also a brilliant mathematician, helped revolutionize science in a number of ways. Rather than speculating about motion, Galileo experimented with it. After his experiments, Galileo concluded that objects were in a state of motion until a force stops the motion. This idea flew in the face of the physics of Aristotle and other classical philosophers, who said that rest was the natural state of objects.
Galileo learned about the invention of a telescope and built one himself. With his telescope, Galileo, already a supporter of the Copernican hypothesis, got himself into trouble. He discovered that Jupiter had moons, that the sun had sunspots, and that the moon had craters everywhere. These discoveries further debunked the old worldview that the planets were embedded in crystal spheres and that the heavenly bodies were made of a perfect matter different from that which composed the Earth.
As Galileo wrote more and more, he caught the attention of theologians in Europe who reported him to the pope and to the Inquisition. The pope granted Galileo permission to write about his theories as long as he didn’t hold them as truths. Furthermore, the Inquisition determined that the Copernican idea of nonstationary Earth was heretical. As Galileo aged, he worked on his most important work, Dialogue on the Two Chief Systems of the World, which was published in 1632. Galileo often wrote in an arrogant, condescending tone and such was the case with this work. It was also a little more forward-leaning than the pope had hoped it would be. As a result, Galileo found himself on trial for heresy. (More on that later.)