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Throughout the history of modern astronomy the scientific method has played an important role in helping to guide scientist in correctly modeling a theory of how our solar system interacts in the whole cosmology of the universe. The history of scientific method and the history of astronomy seem to develop hand in hand. A development in astronomy seems to coincide with a refinement in the method of studying the sciences. The ancient Egyptians, using a form of the method in their surgical manuals, stated the basic forms of examination, diagnosis, treatment, and prognosis. The ancient Greeks formalized at tradition of a scientific method that included some of the steps that we include today. However, it was during the renaissance period that we get a more defined version of a method. The philosopher/scientists Descartes, Hume, Kant, and Newton all played a part in defining this process and in turn used it to prove to the world that the model of the universe was not geocentric, but was in fact, heliocentric, the Earth revolved around the Sun.

The Heliocentric model of the solar system was put forth by an ancient astrologer  Aristarchus of Samos in 200 BCE, however without any method to prove this theory, this model was overshadowed by the geocentric model of the Solar System and common sense.The method commonly accepted today, in its simplest form, includes the following four steps: The first step involves observing and describing a phenomenon or group of phenomena. The ability to observe what was happening up in the heavens in ancient times was limited at best. With out the aid of telescopes ancient man resorted to using mathematics to explain what the thought they saw in the sky. Claudius Ptolemy (85 -165 CE) used mathematics to portray a very complicated geocentric model trying to explain how the sun, the moon, the stars and the planets revolved around the Earth. This model of the universe was accepted by the Catholic Church and survived and prevailed for almost 1400 years due to the church’s heavy influence.

Polish astronomer/astrologer Nicolaus Copernicus (Latinized version of Nicolaus Koppernigk) employed the second step of the scientific method to formulate an hypothesis to explain the phenomena of the retrograde motion of the planet Mars. In order to do this, Copernicus needed to propose the hypothesis that the Sun is the center of our Solar System and not the Earth. This heliocentric model of the universe probably would have caused a lot of trouble for Copernicus by the Catholic Church as he was trained in his youth as a cleric. A quick side note: Charles Darwin who, three hundred years later would also cause uproar in all of Christianity with his theory on the origins of the species, was also trained in his youth as a cleric. Copernicus waited till he was no his death bed to publish his great work, “De Revolutionibus “ in 1530. Although Copernicus was on the right track, Copernicus still held to the ancient Greek thought that the planets revolved around a center in a perfect circle.

It wasn’t for another 100 years that the third step in the scientific method took the field of astronomy a bit further on the path of solidifying the heliocentric model of the solar system and eventually the universe. Standing on the shoulders of those who went before him was Danish astronomer Tycho Brahe. Brahe maintained that geocentric model with the Sun and the Moon revolving around the Earth, yet a heliocentric solar system model with the planets revolving around the sun. Brahe was trying to utilize hypothesis based on either the Ptolemaic or the Copernican models and not getting the right answers for either so he came up with his own, the geo/heliocentric model of the universe. Working to predict the planets positions accurately as the Imperial Mathematician to the Holy Roman Empire, Brahe hired Johannes Kepler to help with the math that was needed to prove his model. Upon Brahe’s death, Kepler went on to help solidify the proof that the Sun was the center of the system and the Earth revolved around the Sun, not in the perfectly circular motion that Copernicus and the ancients thought, but in the pattern of an ellipse. In using an elliptical model of the planet’s movements, Kepler was able to accurately predict the existence of other phenomena and the results of other new observations.

During the late 15th and early 16th centuries, the rationalist and empiricist philosophical movements were taking place in Europe. These renaissance philosophers were working to explain the world without having to rely on mysticism and religion as the basis of science. Instead Descartes, also trained by the Catholic Church threw out all that he had been taught and started fresh. The basis for laying out a method was published in 1637 the “Discourse on the Method.” Relying on the works of Galileo, also a contemporary of Kepler and a believer in the Copernican model, Descartes made huge strides in the workings of analytic geometry.

Galileo Galilei tied the first three steps of the scientific method together as used the first telescopes to observe and record the sky. Brahe had done this before with machines that would aide in recording the positions of stars and planets utilizing naked eye observations. With the use of the telescope Galileo felt justified by his observations that the Copernican (heliocentric) model was the correct view of the solar system. Galileo did this by publishing his support of the heliocentric model in the book, “Dialogue Concerning the Two Chief Systems of the World – Ptolemaic and Copernican”. In doing so Galileo was accused of heresy by the Catholic Church and placed under house arrest for many years. The heliocentric model was once again put before the public and found new believers before this battle with the Church was lost. The war continued.

Following the first three steps of the scientific method have led us through the centuries  to a man who would unify the world of physics and astronomy and take the final steps in using the scientific method to verify the heliocentric model of the Solar System and the Universe. The man who brought everything together is Sir Isaac Newton. Johannes Kepler had proposed three Laws of Planetary motion based on the systematics that he found in Brahe’s data. These Laws were supposed to apply only to the motions of the planets; they said nothing about any other motion in the Universe. Further, they were purely empirical: they worked, but no one knew a fundamental reason why these laws should work. Newton showed that Kepler’s Laws of planetary motion were approximately correct, and supplied the corrections that with careful observations proved to be valid. This is part of the fourth step of the Scientific Method: Experimental tests of the hypothesis of Galileo and Kepler showed that Kepler’s Laws followed Newton’s newly formulated Laws of Gravitation.

Men like Rene Descartes, who became the ultimate skeptic of all knowledge imparted to him during his schooling was determined to follow a method of observation rather than on faith. Men like Kepler who hypothesized and worked to prove his hypothesis, men like Galileo who was willing to suffer for his belief in the truth of what he saw. Today we have men like Steven Hawking who have the vision to work toward the future.  Throughout the centuries and with the hard work of many men, the heliocentric view of the Solar System has prevailed. Not only Astronomers use this method, but all men of science.

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Scientific Method