Nicholas Copernicus De Hypothesibus Motuum Coelestium a se Constitutis Commentariolus (A Commentary on the Theories of the Motions of Heavenly Objects from Their Arrangements):
  1. There is not a single center for all the celestial orbs or spheres [the Sun is one center of motion, for the planets; the Earth is another, for the Moon]

  3. The center of the Earth is not the center of the world [the Sun is the center of the world], but only of the heavy bodies and of the lunar orb [rocks fall toward the center of the Earth and the moon circles the Earth]

  5. All the orbs encompass the sun which is, so to speak, in the middle of them all, for the center of the world is near the sun [the planets have orbits or spheres centered on the Sun]

  7. The distance from the sun to the earth is insensible [so small as to be not measurable] in relation to the height of the firmament [the stars are much, much more distant than the Sun]

  9. Every motion that seems to belong to the firmament does not arise from it, but from the Earth. ...  the  firmament, or last heaven, remains motionless. [This is  Oresme's  idea: the Earth turns while the stars remain still.]

  11. The motions that seem to us proper to the Sun do not arise from it, but from the Earth and our orb, with which we revolve around the sun like any other planet.   In consequence, the earth is carried along with several motions. [The Sun is still.  The Earth experiences two fundamental motions: rotation on its axis, which gives us day and night, and revolution around the Sun, which gives us the year and the seasons. An additional motion, known as precession, accounts for the 26,000 year period discovered by Hipparcus . The Earth is treated "like any other planet."]

  13. The retrograde and direct motions which appear in the case of the planets are not caused by them, but by the Earth.  The motion of the Earth alone is sufficient to explain a wealth of apparent irregularities in the heavens. [Retrograde motion occurs when the  Earth " laps" an outer planet or an inner planet "laps" the Earth. The planets do not actually slow down, stop, and reverse directions when they are seen to go retrograde.]

In 1543, he would publish the book De Revolutionibus Orbium Celestium [The Revolutions of the Celestial Orbs]


Advantages of the Copernican system:
Comparison of Distances of Planets to the Sun
(in Astronomical Units: 1 AU)
Planet Copernicus' value for distance to planet from Sun Modern value
Mercury 0.3763 AU 0.3871 AU
Venus 0.7193 AU 0.7233 AU
Earth 1 AU 1 AU
Mars 1.5198 AU 1.5237 AU
Jupiter 5.2192 AU 5.2028 AU
 Saturn 9.1743 AU 9.5388 AU
stars 7,850,000 AU
1 AU 1142 solar radii 23,456 solar radii

By the end of the sixteenth century, the total number of astronomers (Michael Maestlin) and others of influence (Giordano Bruno) who agreed with Copernicus could be counted on a few fingers (if that many were needed) of one hand. If heliocentric astronomy was so successful, why didn't the astronomy community accept heliocentrism immediately?

Copernican timeline:

Council of Trent:

Copernicus was challenged by leading Catholic leaders and Protestant reformers who opposed heliocentrism because it contradicted several pieces of scripture.   The idea that the Earth moved, that the Earth was not at the center of the universe, was in contradiction to how these passages had been interpreted by respected Catholic Church authorities as being consistent with a geocentric cosmos and with how Protestants (who were more literal in their interpretations than were the Roman Catholics)  Biblical verses that were often cited as proof that Copernicus was wrong include:

So Copernicanism had an uphill battle to fight if it were to gain acceptance.

"The book had to fights its battles without further help from its author.  But for those battles, Copernicus had constructed an almost ideal weapon.  He had made the book unreadable to all but the erudite astronomers of his day."  -- Thomas Kuhn, The Copernican Revolution
Armed with literal translations of these verses, Protestant reformers had all the ammunition they needed to attack Copernicus and his ideas.Luther (in 1539):
"People gave ear to an upstart astrologer who strove to show that the earth revolves, not the heavens or the firmament, the sun and the moon. ... This fool wishes to reverse the entire science of astronomy; but sacred Scripture tells us [Joshua 10:13] that Joshua commanded the sun to stand still, and not the earth."
Melanchton (Luther's close collaborator and friend) wrote, in 1549:
"The eyes are witnesses that the heavens revolve in the space of twenty-four  hours. But certain men, either from the love of novelty, or to make a display of ingenuity, have concluded that the earth moves; and they maintain that neither the eighth sphere [the celestial sphere] nor the sun revolves.  ... Now, it is a want of honesty and decency to assert such notions publicly, and the example is pernicious. It is the part of a good mind to accept the truth as revealed by God  and to acquiesce in it."
"Who will venture to place the authority of Copernicus above that of the Holy Spirit?"
Jean Bodin, a political philosopher who opposed Machiavelli's views, and whose writings were all placed on the Index of banned books in 1628, wrote:
"No one in his senses, or imbued with the slightest knowledge of physics, will ever think that the Earth, heavy and unwieldy from its own weight and mass, staggers up and down around its own center and that of the Sun; for at the slightest jar of the Earth, we would see cities and fortresses, towns and mountains thrown down. ... all things on finding places suitable to their natures, remain there, as Aristotle writes.  Since therefore the Earth has been allotted a place fitting its nature, it cannot be whirled around by other motion than its own."
By mid-sixteenth century both the Church of Rome and the leaders of the Protestant movements all agreed, though for different reasons, that Copernicus' ideas were wrong.

Thomas Kuhn writing in The Copernican Revolution (1957):

"When it was taken seriously, Copernicus' proposal raised many gigantic problems for the believing Christian. If, for example, the earth were merely one of six planets, how were the stories of the Fall and of the Salvation, with their immense bearing on Christian life, to be preserved? If there were other bodies essentially like the earth, God's goodness would surely necessitate that they, too, be inhabited. But if there were men on other planets, how could they be descendants of Adam and Eve, and how could they have inherited the original sin, which explains man's otherwise incomprehensible travail on an earth made for him by a good and omnipotent deity? Again, how could men on other planets know of the Saviour who opened to them the possibility of eternal life? Or, if the earth is a planet and therefore a celestial body located away from the center of the universe, what becomes of man's intermediate but focal position between the devils and the angels? If the earth, as a planet, participates in the nature of celestial bodies, it can not be a sink of iniquity from which man will long to escape to the divine purity of the heavens. Nor can the heavens be a suitable abode for God if they participate in the evils and imperfection so clearly visible on a planetary earth. Worst of all, if the universe is infinite, as many of the later Copernicans thought, where can God's Throne be located? In an infinite universe, how is man to find God or God man?

"These questions have answers. But the answers were not easily achieved; they were not inconsequential; and they helped to alter the religious experience of the common man. Copernicanism required a transformation in man's view of his relation to God and of the bases of his morality ..."