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The Church and Copernicus

The Church and Copernicus | Galileo Galilei | Tycho Brahe and Johannes Kepler | Isaac Newton

Pre-20th Navigation


The Christian Church's doctrine was pretty much solidified 1500 years ago. It had been heavily influenced by Greek and Roman philosophers, especially in its views of science. Among those teachings lay the solid belief in a geocentric universe, very much advocated by Aristotle (384-322 B.C.) and expanded by Ptolemy (A.D. 85-165). "Geocentric" means Earth -centered - the Earth is the center of everything, and especially the center of the solar system.

However, with the Scientific Revolution that went hand-in-hand with the Renaissance of Europe, there was a resurgence of classical studies, such as the teachings of Plato - who advocated a heliocentric universe - but also a new way of viewing the world: The people of the Scientific Revolution wanted to base everything in provable or observable basis.

Geocentric Model

As discussed in the Ancient Greeks section, the geocentric model had seemingly logical evidence. First of all, if the Earth were moving, then wouldn't we feel it, or feel a strong wind in the direction of movement? Also, if the Earth really moved around the sun, then wouldn't we see the stars move? This last phenomena, called parallax, is a real thing, but is much too small to be seen without a telescope due to the extreme distance to stars.

Besides these arguments, the geocentric model puts humans in a special place at the center of everything. Think of it this way: You are trying to recruit people to your belief system, a system that, during its conception and for the first several hundred years it was around, people were persecuted for. It is human nature to want to feel special. Therefore, your religion offers as one of its fundamental beliefs that you are not only a special person, created personally by your divine being, but you live in a special place: At the center of everything.

Simplified Geocentric ModelHowever, even with this reasoning, there were stronger reasons to believe in a heliocentric model. But, this thinking was lost, and the preponderance of the Ptolemaic system pervaded thought for nearly 1.5 millennia.

But, the geocentric model was not simple. If everything were to orbit about Earth, then they should have a regular motion in a constant direction. This model would be represented by the Earth surrounded by spheres upon which the planets, moon, and sun would move, plus a sphere for the fixed stars.

This is not accurate, for there were times when planets would move in a retrograde direction. In an attempt to account for this, scientists added extra circles onto the spheres. Thus, the planets moved upon the little circles, and the little circles moved on the bigger circles. These circles upon circles were called "epicycles," and the larger circles were called "deferents." This is shown in the image to the right. This is a "three planet" system, with the Earth at the center, and two planets around it. The red and yellow circles represent the deferents, while the green and orange the epicycles. The green and orange balls represent the two planets.

Enter Copernicus

Nicholas CopernicusThe Polish astronomer Nicholas Copernicus (1473-1543) never liked the Earth-based view of the universe, yet he did not publicly announce his views until he was old. This was due to the Church -- anyone who opposed Church doctrine was branded a heretic, and that would destroy your reputation, put you in prison, sentence you to death, or all of the above.

Copernicus did not invent the idea of a heliocentric - sun-centered - system, but he was the first modern person to advance it. The heliocentric model was able to easily explain things that the geocentric system had a hard time doing, most notably the seemingly retrograde motion of the planets. The planets usually follow an eastward direction in the sky, but sometimes they mysteriously flip and travel westward. The geocentric model attempted to solve this by adding extra orbits upon orbits that the planets would follow. However, the heliocentric model explains this with the Earth simply reversing direction of movement relative to the planet being observed.

Copernicus' publication On the Revolution of the Celestial Spheres was not published until after he died in order for him to avoid being persecuted by the Church. What followed is often called the Copernican Revolution, but this actually was not much of a revolution. The book was published in Latin, so the general public was not able to read it. Academics could, but few learned people were willing to face the Church and risk death. It wasn't even until 73 years after it was published, 1616, that the Church consider it important enough to place on its Index of Prohibited Books.

However, it did put heliocentric views out in the restricted open, and it was useful to people such as Galileo to help revolutionize astronomy in Europe.

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