Tycho Brae to Galileo

Brae and Kepler: Tycho Brae (1546 – 1601) was born into a Danish noble family and planned for a career in government, but became obsessed with science at an early age. As a child, he saw a solar eclipse occur exactly when predicted and later observed that it was "something divine that men could know the motions of the stars so accurately that they were able long time beforehand to predict their places and relative positions." As an adult, he became an imposing man who exploited his peasants with little regard for their welfare. He had lost a portion of his nose in a duel, and wore a special bridge piece made of gold and silver alloy to replace it. He was educated abroad and became Europe’s leading astronomer with his observations of a new star discovered in 1572, the same exploding star which seemed to disprove Aristotle. He accumulated massive amounts of data, but had a limited understanding of mathematics, and was unable to effectively analyze the data he collected. His belief in the nature of the Solar System was part Ptolemaic and part Copernican: He was convinced that the planets other than the earth revolved around the sun, and that the five known planets and the sun revolved around the earth and moon system. Brae argued that if Copernicus had been right, then a cannonball fired from west to east would travel farther in that direction (Copernicus believed that the earth rotated from west to east) and that a weight dropped from a very tall tower would fall west of the tower because of the movement of the earth.

Aside from these errors, Brae’s calculations were inaccurate at times. This fact illustrates that the Scientific Revolution did not proceed in straight line fashion, but like many great accomplishments, had a number of false starts and wrong turns.

Johannes Kepler (1571 – 1630) was Brae’s assistant. He had been trained for the Lutheran ministry, and was a thoroughly medieval figure. His mother practiced astrology, and was condemned to be burned at the stake, but he managed to save her through a convoluted legal process. Kepler was something of a mystic, who claimed that he had correctly predicted a harsh winter, and peasant uprisings in Germany. He believed that the universe was built on "mystical mathematical principles," and there was a certain musical harmony that existed between the heavenly bodies—literally, "the music of the spheres." Kepler faced persecution from Lutherans because of his views and was protected by Jesuits when he fled to Austria, but had to leave that country when he refused to convert to Catholicism. Brae from his deathbed implored Kepler to continue his work, and the Holy Roman Emperor, Rudolph II, appointed Kepler as imperial mathematician. Kepler reworked and reanalyzed Brae’s data and eventually formulated three important laws of planetary motion:

  1. In 1609, he demonstrated that the orbits of the planets were elliptical rather than circular. This solved the problem of Copernicus and disproved Ptolemy’s theory of erratic orbits. He theorized that the stars were distinct from planets and had separate properties, which argued against Aristotle’s crystal sphere position.
  2.  He demonstrated that the planets do not move at a constant speed. Rather it traveled at a faster rate of speed when it reached its perigee (closest point to the object it orbits, and a slower speed when it reached its apogee (furthest point). Some previous work had been done on magnetism in Britain, and relying on this work, Kepler concluded that magnetic force from the sun and earth attracted each to the other. He further theorized that this magnetic force was responsible for rising and falling ocean tides.
  3. In 1619 he demonstrated that the time required for a planet to complete its orbit was directly related to its distance from the sun.

Kepler managed to prove mathematically the precise relationship between the sun and planets. His work completely destroyed the old Aristotelian and Ptolemaic theories of the universe. He came close to, but did not demonstrate, the law of universal gravitation. His conclusions also indicated that the hand of God was not needed to move the planets along in their orbits, which brought him into serious conflict with the position of the church.

Sir Francis Bacon: Sir Francis (15461 – 1626) who called himself "a bell ringer who is first up to call others to church," was a lawyer, philosopher, and statesmen and helped separate Science from philosophy. He argued that medieval scholasticism had preoccupied itself with issues which had no practical consequences, often illustrated by the famous, "how many angels can dance on the head of a pin." Tradition, he argued, had no place in science, and he called for "a total reconstruction of science, arts, and all human knowledge."

Bacon’s work involved inductive reasoning: proceeding from observation and experimentation to conclusions or generalizations, that is from the specific to the general. (Aristotle had argued for deductive reasoning, proceeding from the general to the specific.) He argued that the truth of the universe could be revealed by scientific experiment, not by religion, and wrote, "Arts and sciences should be like mines; where the noise of new works and further advances is heard on every side." Scientists, he argued, should specialize, and work in cooperation to "overcome the necessities and miseries of humanity." Bacon is considered the father of the modern Scientific Method.

Sir Francis was famous in his own day, as he was Lord Chancellor for King James I of England which helped stir interest in science in that country, although it was limited to a small number of people. He only held the position for three years before he was fired for accepting a bribe. His actual scientific work was also of little value. He died after catching a cold during an experiment in which he stuffed snow into a dead chicken. That chicken obviously was not a gamecock, because no one, not even a Clemson Tiger, can "stuff" them.

Galileo: Galileo Galilei was born to a poor but noble family in Florence, Italy. He was fascinated by mathematics, and was demonstrably brilliant. He became professor of mathematics in 1589 at the age of twenty five. Although he did not theorize it, Galileo was one of the first to employ the modern scientific method, in that he conducted experiments to determine what would happen. His most famous experiment demonstrated the law of acceleration: a uniform force (gravity) would produce uniform acceleration. Two objects in a vacuum would fall at the same speed regardless of weight or volume.

In his Two New Sciences, Galileo demonstrated his conclusions:

A piece of wooden moulding…was taken on its edge was cut a channel a little more than one finger in breadth. Having made this groove very straight, smooth and polished, and having lined it with parchment, also as smooth and polished as possible, we rolled along it a hard, smooth and very round bronze ball…. noting….the time required to make the descent….we now rolled the ball only one quarter the length of the channel, and having measured the time of the descent, we found it precisely one half of the former….In each experiment [over many distances], repeated a full hundred times, we always found that the spaces traversed were to each other as the squares of the times, and this was true for all inclinations of the plane.

Galileo also formulated the law of inertia. The natural state of an object was not rest, but motion. An object would remain in motion unless stopped by a superior force. This was completely opposite Aristotle’s theory, which was not completely discredited. He also postulated that the air and clouds of the earth move as it rotates, although they appear stable to an observer on the surface of the earth. Galileo’s rooms for experimentation in his house became the first true scientific laboratory.

He also became interested in astronomy, built his own telescope, and discovered four moons rotating the planet Jupiter. The presence of the moons also discredited Aristotle’s argument that the planets moved inside an impenetrable crystal sphere, and further verified the theories of Copernicus. Galileo also observed the rings of Saturn, and observed sun spots as they moved across the surface of the sun, which suggested to him that the sun itself also rotated on an axis.

Galileo often sought practical information from craftsmen and artisans. He consulted workers who built cannon, soldiers, and people who made compasses, astrolabes, navigation instruments, even water pumps. He did not care whether his work reached ordinary people, but believed that "the mobility of the earth is a proposition far beyond the comprehension of the common people." He said that the "all too common vulgar" should remain ignorant of his findings, "lest they become confused, obstinate, and contumacious."

In Siderius Nuncius (the Starry Messenger), Galileo described his finding when he viewed the moon through his telescope:

I feel sure that the moon is not perfectly smooth, free from inequalities and exactly spherical, as a large school of philosophers considers with regard to the moon and the other heavenly bodies. On the contrary, it is full of inequalities, uneven, full of hollows and protuberances, just like the surface of the earth itself which is varied….The next object that I observed was the essence or substance of the Milky Way. By the aid of a telescope, any one may behold this in a manner which so distinctly appeals to the senses that all the disputes which have tormented philosophers through so many ages are exploded by the irrefutable evidence of our eyes, and we are freed from wordy disputes upon the subject. For the galaxy is nothing else but a mass of innumerable stars planted together in clusters.

NOTE: Galileo did not invent the telescope himself. It was invented in Holland, but when he heard about it, he constructed his own.

Galileo worked in Florence for the Medici family, and his work soon drew attention from theologians. He also worked in Padua, and tried to reconcile his work and the work of Copernicus with the teachings of the church. He was mulish and feisty, however, and insisted that the universe was mathematical to the core, and subject to the laws of mechanics which could be discovered. This brought him into conflict with religious authorities. In 1610, he wrote to Kepler "Here at Padua is the principal professor of theology, whim I have repeatedly and urgently requested to look at the moon and planets through my glass, which he obstinately refused to do. Why are you not here? What shouts of laughter we should have at this glorious folly!"

The pope condemned Galileo’s proposition that the earth rotated around the sun, in 1616 and warned him not to teach it. Galileo, feisty and stubborn to the end, published his Dialogue Concerning Two World Systems: Ptolemaic and Copernican, in which he presented a dialogue between those espousing the positions of the two. Ptolemy’s position was supported by a character whom Galileo named "Simplicio," an obvious taunt. The very name outraged church authorities who believed (correctly) that the character was intended as a caricature of the Pope..

In 1632, Galileo published his Dialogue on the two Chief Systems of the World in Italian, which lampooned the arguments of Ptolemy and Aristotle. Pope Urban VIII, who had been Galileo’s friend, had permitted him to write about different possible systems of the world on condition that he not presume to judge which actually existed. Urban was not pleased with Galileo’s remarks, and had him arrested by the Inquisition. The church’s major objection to his work was that he adopted an atomistic view of matter (it cannot be changed from one element to another), which directly contradicted Aristotle’s position and in the church’s eyes denied that transubstantiation (the conversion of the bread and wine of the Eucharist into the body and blood of Christ.) Urban also had political considerations. The Papacy had been weakened by the Protestant Reformation, and Urban did not feel the church could stand to be proven wrong. Galileo was accused of supporting the work of Copernicus rather than outright heresy; had he been charged with the latter, he could be sentenced to death. He was imprisoned and threatened with torture, under the influence of which he repudiated his earlier findings, "renouncing and cursing" his previous work as heresy, and was sentenced to house arrest for life. Even so, as guards escorted him to his home, he glanced up at the sky and proclaimed of the earth, "see, it’s still moving." Galileo continued to work from his house, and smuggled his works to Holland where they were published. In 1638, when he went blind, the Pope refused to allow him to leave his house to consult a doctor in Florence. Even though blind, Galileo continued his work until his death five years later.

The Human Body: Aristotle, in addition to his other worthy endeavors, had dissected human bodies to determine how the body functioned. He concluded that the body had four "humors," blood, phlegm, yellow bile and black bile. He postulated that disease resulted from an imbalance in these humors. Aristotle’s work was enhanced by the work of Galen (129 - c.210 C.E.) who performed experiments on apes, whom he assumed had the same organs and body structure as humans. Galen concluded that two types of blood caused muscle movement and digestion; bright red blood which flood up and down through the arteries, and dark red blood which flowed through the veins.

With the advent of Scientific discovery, many scientists believed that the function of the body could be explained scientifically, and explained by universal laws. Andreas Vesalius: (1514 – 1564) was the first modern scientist to dissect human bodies and was the first to construct a human skeleton. (Although Aristotle had dissected human bodies, the church had forbidden this practice during the Middle Ages as sinful.) He published On the Fabric of the Human Body in 1543.

William Harvey (1578 – 1657) first explained circulation of the blood. Harvey adopted a scientific methodology, as had the astronomers of the era. He once remarked, "I profess to learn and teach anatomy not from books but from dissections; not from the tenets of philosophy but from the fabric of nature. Harvey worked before the invention of the microscope, and seldom used even a magnifying glass; however he did theorize that the heart was a pump which circulated blood through the body. Even he was not without some erroneous predisposition, however. He believed that the blood contained "vital spirits" necessary for survival. His work did, however, establish the basis for modern biology and medical study.