Copernican Revolution Continued


The first great telescopic observer was Galileo Galilei, an early convert to Copernicanism who made no secret of his beliefs. From his youth (birthdate February 15, 1564), Galileo displayed the traits that were to dominate his life. He frequently questioned the authority of his professors, refusing to accept their dogmatic statements and demanding proof with observation rather than blind acceptance of some authority (not much unlike Martin Luther's ideas regarding priest-only interpretation of the Bible). A great connecting website which details the discoveries of Galileo can be found by clicking on his image to the left, or you can refer to a detailed biography by clicking on Galileo.

When he was only eighteen and studying at the Pisa, he noticed that the cathedral lamp oscillated at consistent times, no matter how heavy the object, nor how wide the oscillations. He verified his findings with his own pulse, and concluded that all which mattered was the length of the cord. He constructed pendulums which helped doctors determine pulse rates of patients. He would have continued a promising career in medicine until he witnessed a supernova in the Serpens constellation in 1604. In the same observational manner as Tycho, Galileo determined that the star was a fixed star and not a wanderer.

In the winter of 1609-1610 he made a series of spectacular discoveries. Many students of Astronomy believe that Galileo invented the telescope. In actuality, the telescope was invented by a Danish glassmaker. Galileo learned of the invention and ground his own lenses and constructed his own nine-power telescope. What set Galileo apart from other telescopic observers was that he took his trained scientific eye and looked at the night sky with the small instrument. Imagine his amazement at what he saw. He reported seeing mountains and craters on the moon. He watched the terminator of the moon and discovered deep craters with pinnacles in the middle. He even estimated their depth and height to be four miles. He described the dark areas on the moon as being filled with water and he noticed the absence of clouds.
Since the moon was considered to be a perfect sphere of crystal, Galileo was sharply criticized. Undaunted, he continued to study and resolved the seven naked-eye stars of the Pleiades to contain over 40, and that the Milky Way was composed of millions of stars.
He looked at the wandering stars and found them to resolve into disks instead of points of light like the fixed stars. Venus was sometimes a crescent and other times gibbous, an observation clearly in support of the Copernican view of the solar system. He also observed the larger satellites of Jupiter, and since these four bodies were clearly circling the planet, he reasoned that it was a mini model of the solar system.

The motions of the moons of Jupiter, as recorded by Galileo in 1609, and published in his paper, Siderius Nuncus (The Starry Messenger) in 1610 is seen to your right. This may have been the most damaging blow to the geocentric model which was being held on to so strongly by the religious leaders in the Vatican. In their collective reasoning, God placed man, the special object of His creation, at the center of all. Suddenly, Galileo demonstrates that some celestial objects are not revolving around the earth, but around Jupiter. This was heresy number one in the eyes of the Vatican. What complicated matters even more so for Galileo was his contention that Scripture was compatible with the Copernican view, but only if one understood the Bible's intention to be more focused on mankind's relationship with God than on attempts to explain natural phenomenon to its audience. Verses which describe the sun standing still or moving backward need not be taken literally.

When he wrote of his discovery that the sun had spots in 1611, he was openly denounced. For the Sun to have spots was considered a blemish on the very person of God. How could the Sun, giver of life and light and representation of God possibly have dark spots. This could imply sin in God and therefore was impossible to accept. (Please keep in mind that the Chinese had been recording sunspots for centuries, but the Great Wall which was built to keep invading hordes out also served to keep good scientific discoveries in).






Galileo wrote of his findings in several short scientific papers, but more likely it was his attempts to interpret Scripture for his readers which brought the attention of the Vatican to bear down upon him. He was quickly brought before Cardinal Roberto Bellarmine between 1613 and 1616. Galileo was an accomplished and renowned scientist, so the Church was not interested in creating a large public controversy. However, when Galileo took his telescope to the rooftops, the Vatican emissaries refused to believe their very eyes. They claimed that these dark spots on the sun and bumps on the moon were the result of imperfections in Galileo's glass. Galileo returned with new lenses, but now the leaders cited the sin of the world blocking the truth from the heavens and tainting the images of God's creation. Galileo was threatened with excommunication and its ensuing eternal damnation. Galileo was encouraged to stop publishing and stop promoting his astronomical discoveries, and his books were placed on the Index of Forbidden Books, along with the writings of Copernicus. Basically, "keep your mouth shut Galileo, and stay out of trouble." His papers were banned from public reading, but Galileo was allowed to continue his research.

In 1624, the newly elected Pope Urban VIII was found to be sympathetic to the science of Galileo and he began to compose a new treatise on the workings of the celestial planets. He wrote the Dialogue Concerning the Two Chief World Systems in 1632. In this work, Galileo wrote of three individuals who were debating the Copernican and Ptolemaic views from various perspectives ... one being that of the Church. The dialogue between Salvitari, Sagredo, and Simplicio is really an interesting read, but you can do this on your own time later. Suffice it to say, Pope Urban VIII was extremely offended by the manner in which he was presented and the negative light cast upon the Church. Following the publication of his Dialogues, he was again brought before the Inquisition in 1633.

The book title page appears to your left, while an artistic rendition of the Inquisition appears below. He was brought to in Rome in 1633 and after heated debate, forced to recant. Instead of burning Galileo as Giordonno Bruno had suffered in 1600, Galileo was faced with a potentially more severe punishment ... excommunication. This meant loss of membership in the Church, eternal damnation to Hell after death, and eternal separation from God proved more than he could bare so he recanted and lived the remainder of his life under house arrest.







He was forced to 'curse, abjure and detest' the heretical idea that the earth moves around the sun condemned to prison, and required to repeat the seven penitent psalms once a week for three years. The following day, the Pope Urban VIII altered the sentence to mere confinement in a country-house near Rome and reciting Psalms of penitence. He was later allowed to return to Florence, where, broken in health and spirit, he still tried to continue his observations. Her had a school of very talented students working under his guidance and he continued to write scientific papers, but without the Scriptural interpretations which landed him before the Inquisition twice. He laid the groundwork for modern Physics with his final work Two New Sciences. Total blindness finished his observations in 1636, and he died in 1642 ... the same year Isaac Newton was born.

A terrific chronology of Galileo accompanies this test, and I encourage you to look it over.

Galileo was the last great scientist to be persecuted for teaching that the earth is an ordinary planet. In 1687 Isaac Newton published his immortal Principia, in which he laid down the laws of gravitation . He also explained many other phenomena, such as the tides. Described as the greatest mental effort ever made by one man, his book marked the beginning of the modern phase of astronomy. Newton was also the first to make a reflector, which collects light by means of a mirror instead of a lens. The mirror had a diameter of only one inch, but it was the forefather of the great multi-meter telescopes of today. The revolution in outlook was complete.

You can now move to Sir Isaac Newton and see how this incredible scientist developed the laws which govern the motion of the planets, and just about everything else.

Where are we now in the history of the Copernican Revolution?

Martin Luther encouraged people to think differently. Instead of blindly accepting what a priest told them the truth to be, read for yourselves and make your own conclusions.

Copernicus dared to rethink the Ptolemaic geocentric model, proposing a heliocentric view. Like Luther, he dared to think differently.

Tycho took detailed notes of the motion of planets against the starry background. While the maps were excellent, he misinterpreted his notes and drew incorrect conclusions. His failure to listen to the opinions of others is an example of personal ego clouding good judgment.

Kepler reevaluated the work of Tycho and offered the correct interpretation of the data. Copernicus was almost completely right. Kepler gave some mathematical proof for the Copernican model.

Galileo provided the observational proof of the Copernican model and Kepler's Laws, but at great emotional and spiritual cost.

Sadly, Galileo's papers were placed on the Papal Index as heretical literature. In October, 1994, these papers were removed from that list by decree of the Roman Catholic Church. While we might cringe to think that it took so long for the Vatican to recognize their mistake, the real reason for the delay is more subtle. It had long before been recognized that Galileo was correct. What required such careful consideration was treatment of those who placed him before the Inquisition and banned the books. Should they have been punished for their harsh treatment? After consultation for so many years, the issue apparently was resolved and Galileo exonerated.

*** I received a copy of a fascinating book by Dava Sobel entitled "Galileo's Daughter." While few of Galileo's works remain, Sobel found the letters which were written to Galileo by one of his three children, daughter Maria Celeste ... a cloistered nun. Penguin Group publisher, copyright 2000. ***

Forward to Newton, or back to Copernicus, Tycho, Kepler, Introduction to the History Unit, the Syllabus, or the Home page.

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