from the Romans and the Greeks to better understand the world around them.

Transcription

1 During the 14 th and 15 th centuries thinkers and scholars looked to ancient texts from the Romans and the Greeks to better understand the world around them. Astronomers looked back to texts from Aristotle ( B.C.) and Ptolemy (A.D ). This brought about a power struggle between those who followed Geocentric theory, which states that the earth is the center of the Universe and those who followed Heliocentric theory which places the sun at the center. Those that went with church dogma saw the beliefs set fourth by Aristotle in Greece and Ptolemy in Egypt as the way the Universe was arranged with the Earth being the center of all things. Geocentric thinking worked better for the church because the bible was written in such a way as to represent the earth of the center of all things. Those such as Galileo Galilei ( ) and Nicolaus Copernicus ( ) saw these ancient ideas represented in texts such as On The Heavens and Physics by Aristotle and Almagest by Ptolemy as flawed and untrue of the real Universe. Although mostly keeping out of the public eye for fear of execution by the Church, both Galileo and Copernicus spent the majority of their lives disproving the church dogma as well as Hellenistic astronomical thinking. There work both led to a new age in Astronomy and helped to spark the sea of ideas both new and old that were so prominent during this time period. Why choose These Documents? I chose the documents of Galileo and Copernicus mostly because of my pure interest of the topic. I have always been curious about the Universe and often I can be found out gazing at the stars through my telescope. However, that is not the only reason why I chose these documents. It occurred to me that throughout the Renaissance scholars

2 were rediscovering documents from ancient societies and were using them to further advance their culture at the present. When reading these two documents I realized that in this case documents from Ptolemy and Aristotle concerning the Universe were completely wrong and the people of the Renaissance were using them despite the availability of better theories. Aristotle and Ptolemy s views were genius for their time period but were now outdated. Philosophy represented in the document on Copernicus almost completely debunked the philosophies of Aristotle concerning the Universe. After his death it was the science of Galileo that helped to strengthen and prove Copernican theory even more. Unfortunately, because of the great deal of power the Catholic Church had over Europe, both the philosophy and the science were repressed or dejected. Most Universities taught the Aristotelian model of the Universe and had been for centuries. The whole of Europe believed that Aristotle was correct; after all they had been taught his theory for over 4 centuries. In a time of great advancement of society and in logical thought the correct theories about our solar system and the Universe were kept from people. Perhaps during the Renaissance people were so obsessed with the past that they thought scientists and philosophers from then were smarter than the present day scientists and philosophers. Perhaps they just feared change of something that had been a staple in European higher education. Most likely, they probably feared that a new theory would somehow disprove the existence of God that was so key in Aristotle and Ptolemy s works, helping to prove the legitimacy of the bible. In any case Copernicus and Galileo were way ahead of their time when it came to philosophy and science. These documents help to show just how genius they were and how despite the church they published their works so that others could test them and see that they were indeed correct.

3 Documents Similarities and Differences: The documents represented in the Biblobase course pack by Copernicus and Galileo are similar but are also very different. Both documents work together over two centuries to prove the Copernican theory. This was of course done in spite of earlier works by Ptolemy and Aristotle who combine to form Ptolemaic theory. Copernicus s document focuses mainly on the philosophy and ideas of the universe and does not include any of the science. This is both because we wanted to put the science in a more complete later work but also that with the math the church might see the idea as more than a hypothesis and keep Copernicus from continuing his work. Galileo s document contained more science and went a step further to include sketches. Although discovering moons on a distant planet may not seem to have anything to do with a theory that puts the sun at the center of our solar system, in fact this discovery helps to prove that it is unlikely that we have a earth centered universe. If moons of a different planet travel around that planet that means those bodies don t rotate just around the earth and would debunk Aristotle s view of a perfect universe. It is no wonder that because Galileo went this extra step to show the science and diagrams that during his lifetime he was threatened with death unless he recanted his findings. These two documents on the outside appear to be about separate topics but in fact were a compliment of each other to help prove to doubters that the Ptolemaic view of the Universe was outdated and was time to switch to Copernican thinking.

4 Ptolemaic Philosophy: The Ptolemaic system is a view of the heavens based largely on the work of Aristotle and the follow up work on Aristotelian theory by Ptolemy. Aristotle argued that the universe was ordered and the heavens fell into two categories, Earthly region and the Heavens with the earth being the center of the cosmos. The Earthly Region consisted of Earth, fire, water, and air. In his view none of these elements existed in the heavenly region. Outside the Earthly Region there was a 5 th element which he called Aether in which encompassed all else in space. Each of these five elements throughout each region occupied a certain sphere in the universe and each elements natural place in the universe was within these spheres. For example the earth is heaviest and is the center of the universe so it falls into the first sphere, where as water and air are lighter so they surround the first sphere. In the Heavenly sphere the laws of the Earthly Region did not apply. Going by brightness, Aristotle thought that in this sphere from the earth outward the heavenly bodies followed this order: Moon, Mercury, Venus, Sun, Mars, Jupiter, Fixed Stars. After the fixed stars Aristotle assumed that god was running this system and that space was finite and after the fixed stars and god the universe ended. During this time period Aristotle s thinking was genius. However, there were several problems that this basic theory could not explain. For example, Planets such as Mars and Venus appeared in different parts of the sky at different times during the year. This was of course due to the fact that each planet rotates around the sun on a different plane, but this was not known during this time period. Many of the planets would also be seen to be traveling in retrograde orbits which is caused by the earths rotation which is why the sun rises in the East and Sets in the west. Aristotle believed this was because the

5 sun orbited the earth and refused to believe that the earth could spin that fast and have the spheres stay in tact. This however caused a problem because at different times of the year the planets would appear to travel in different directions across the sky and his theory could not explain these phenomena. Ptolemy recognized these problems and worked to discover ways to maintain Aristotle s geocentric theory while changing it so as to adapt to these problems. He thought that the best way to prove Aristotle correct was through mathematics so in his book Almagest (142 A.D) Ptolemy put fourth three mathematical theories to answer the questions raised Aristotle s philosophy. He called these three constructions The Eccentric, The Epicycle, and The Equant. In all of these equations, most of which are very hard to understand unless you are a mathematician, the earth is slightly placed off center in order to make the mathematics of planetary rotation and retrograde motion work. This meant that the earth wasn t exactly the center of the universe; however the amount of displacement was so minimal that the church let it go because it still put earth as the closest heavenly body to center and thus the most important to god. Plus, such a slight move was alright as long as the mathematics could work out so people would stop questioning the theory. This theory hit the Christian West around 1200 C.E. and was immediately accepted by the church and universities of the day. Copernican Philosophy: Copernicus was not the first philosopher to view the sun as the center of our solar system. The first to set the theory in motion was Aristarchus of Samos who between 310 and 320 B.C.E. he proposed a sun centered universe. In 200 B.C.E. Archimedes relayed his thinking about a heliocentric system in his book Sand Reckoner, recognizing the

6 legitimacy of Aristarchus of Samos. Throughout the middle ages these theories continued to hang around but were never taken seriously, they were just theories and accompanied no mathematic proof. The Ptolemaic theory on the other hand had the equations of Ptolemy to help prove their legitimacy. It was not until Copernicus that these theories were taken seriously and researched further. During the 15 th century there were problems that began to arise that only the Astronomers could fix. For example, the calendar was way off due to miscalculations in the ancient Greek model. Also, Events such as eclipses of the moon and the sun still could not be explained and although they appeared to have a pattern were still being explained as random in the old model. So during the 15 th century interest in Astronomy rose drastically. The Humanist Georg Peurbach ( ) started to read over texts by Aristotle and Ptolemy to fix any mistakes they might encounter. Although he maintained the overall accuracy of Aristotle, there were several ideas brought into question that peaked Copernicus s interest during his college years at the University of Cracow. In 1543, the year of his death, Copernicus published De Revolutionibus Orbium Coelestium which was published in Nuremberg. In this he launched his idea of a heliocentric solar system in what he called a mathematical hypothesis. This theory easily explained the retrograde movements of the planets without the need of an off center earth as in Ptolemy s equations. However, thinkers of the day immediately rejected the fact that the earth was not at the center. The scientists were very impressed by the math and the over all work and some even created a hybrid Copernican and Ptolemaic view that used Copernican math within the geocentric system. This was first done by Erasmus Reinhold in his Prutenic Tables published in The first major

7 scientist to completely accept his theories was Thomas Digges who published his own book in 1576 titled A Perfit Description of the Coelestiall orbes. Unlike Copernicus, Digges equipped his text with diagrams and illustrations to help further show the legitimacy of the work. During the late 1500 s Copernicus was beginning to have some followers but was slow because the physics to prove his theory would not be invented for another century and a half. It took discoveries by Kepler and Galileo with the aid of telescopes to help bring his theory to the forefront of astronomical thought. Galileo Published Sidereus Nuncius in 1610 and Dialogue Concerning the Two Chief World Systems in Throughout these texts Galileo used his telescope to discover the four largest moons of Jupiter which he named after members of the Medici family. He also brought about the idea that perhaps the bible did allow for a heliocentric universe and that it was just being misinterpreted. In all his texts he challenged a great deal the theories set fourth by Aristotle and with each discovery he made, especially the moons which proved there were heavenly bodies that rotated around bodies other than the earth, Galileo slowly ate away at the false science surrounding the universe opening up the way for scientists to discover the physics that would prove Copernicus correct. These documents are very important to not only the history of the sciences but of culture and society as well. These documents along with other documents by Copernicus and Galileo changed scientific theory forever and are considered among the most important astronomic theorists and discoverers of all time. They also helped to change society. The church and the Universities were stuck teaching the wrong ideas for centuries and refused to change their stand despite the obvious conclusions set fourth in

8 these documents. Over time these theories helped to change the way Universities taught and even changed the stance of the church, which was perhaps the most powerful establishment in Europe during the 14 th and 15 th centuries. Although they were not immediately accepted, together their theories and discoveries changed the world..