by  Lin Van Poucke  and  Sarah Spooren

Nicolas Copernicus

     1.Biography         

Copernicus received a good standard humanist education,  studying first at the university of Krakow (then the capital of Poland) and then travelling to Italy where he studied at the universities of Bologna and Padua.  He eventually took a degree in Canon Law at the university of Ferrara.  At Krakow, Bologna and Padua he studied the mathematical sciences, which at the time were considered relevant to medicine (since physicians made use of astrology ).  Padua was famous for its medical school and while he was there, Copernicus studied both  medicine and Greek.  When he returned to his native land, he practised medicine, though his official employment was a canon in the cathedral chapter.   

In the beginning Copernicus was a schoolmaster in but in 1500 he started teaching mathematics privately in Rome.  In 1543 Nicolas Copernicus died of a cerebral heamorrhage at the age of 70  in Frauenburg in Poland.

 

 

     2. His contribution to science

While he was in Italy in 1513, he  wrote  a short     account of what has since become known as the    Copernican Theory, namely that  the Sun (and not the  Earth) is the middle of the Universe.   Such a model is called a heliocentric system.  Because of his fear for the Catholic Church his theory was not published until the end of Copernicus’s life,  under the title ‘On the  revolutions of the heavenly spheres'. (others called the book “On the Revolutions of the  Heavenly Bodies”). The book was published when Copernicus lay on his deathbed.

Copernicus’s theories was in contrast with some  theories of  important scientists who had published them before him.  Copernicus didn’t discard their theories completely.  He looked at their assumptions and kept the pieces of the puzzle which he felt made  sense.  

In his new ordering, the Earth is just another planet (the third outward from the Sun), and the Moon is in orbit around the Earth, not the Sun. The stars are distant objects that do not revolve around the Sun. Instead, the Earth is assumed to rotate once in 24 hours, causing the stars to appear to revolve around the Earth in the opposite direction.The Copernican system by banishing the idea that the Earth was the center of the Solar System, immediately led to a simple explanation of  the varying brightness of the planets . The planets in such a system naturally vary in brightness because they are not always at the same distance from the Earth.

Copernicus saw that the planet Mars changed in brightness as  it moved in its orbit.  The  explaination of that phenomenon he learned from Ptolemy.  Copernicus tried to explain the change in distance from Mars to the Earth in another way than Ptolemy did.  This lead Copernicus to believe that the earth and other planets moved around the sun constantly.  Planets closer to the Sun moved faster than planets who were further away.  This way, sometimes a planet could be on the same side of the sun as the earth and appear brighter or a planet could  be on the other side of the sun from the earth and appear to be dimmer because it was farther away.   

 

The idea of Copernicus was not really new! because he added the ideas of Aristarchus who put the sun at the center of the universe, and his own observations. Indeed a sun-centered Solar System had been proposed as early as about 200 B.C. by Aristarchus of Samos (Samos is an island off the coast of what is now Turkey). However, it did not survive long under the weight of Aristotle's influence and "common sense": One of the questions raised by Aristotle was : if the Earth is actually on an orbit around the sun, why wasn't a parallax effect observed? That is  : stars should appear to change their position with the respect to the other background stars as the earth moved about its orbit, because of viewing them from a different perspective. Indeed this  objection is valid, but failed to account for what we now know to be the enormous distances to the stars. The parallax effect is there, but it is very small because the stars are so far away that their parallax can only be observed with very precise instruments which were only invented in the 19th century. Thus, the heliocentric idea of Aristarchus was quickly forgotten and Western thought stagnated for almost 2000 years as it waited for Copernicus to revive the heliocentric theory.

 

Copernicus is most famous for his heliocentric model.  By making a heliocentric model and putting the earth at a tilt, he  made a model of the universe that  also was used for many other observations he made, including retrograde motion, the daily movement of the stars and the motion of the sun through the ecliptic.

Copernicus’s model also fit with his religious beliefs. He said that God would have put the sun at the centre of the universe because the sun was perfect.  He also thought that God would have created a simple universe and that his theory was quite simpler than Ptolemy’s.

However the Copernican model was not complete. For instance , Copernicus said that the planets moved in perfect circles and that they all moved all the time at the same speed just like Aristotle already said. So he still needed the theory of Ptolemy to explain the irregular motion of the planets. And his explanation didn't make clear  why we don’t feel the motion of the earth.

 

      3.Other equal-thinking scientists

Many scientists continued working towards a geocentric model, more in line with Ptolemy’s way of thinking.  Just a few of them actually defended the theory of Copernicus.  For example:

-     Johannes Kepler:

Born: 27 December 1571 in Leonberg (in the Holy Roman Empire (now Germany))  
Died: 15 November 1630 in Regensburg (now in Germany)

He is now chiefly remembered for discovering the three laws of planetary motion.  He also did important work in optics, discovered two new regular polyhedra, gave the first mathematical treatment of close packing of equal spheres, gave the first proof explaining how logarithms worked .

-     Galileo Galilei :

Born: 15 February 1564 in Pisa (Italy)  
Died:  8 January 1642 in Arcetri(Italy)

He was a strong defender of Copernicus’s theory.

-     Isaac Newton :

Born: 4 January 1643 in Woolsthorpe England  
Died: 31 March 1727 in London in England

Strong theoretical  underpinning for the Copernican theory was provided by Newton’s theory of universal gravitation.

4. Sources

http://www-groups.dcs.st-and.ac.uk/^~history/PictDisplay/Copernicus.html
http://www-groups.dcs.st-and.ac.uk/^~history/Mathematicians/Copernicus.html
http://www-groups.dcs.st-and.ac.uk/^~history/Mathematicians/Newton.html
http://www-groups.dcs.st-and.ac.uk/^~history/Mathematicians/Kepler.html
http://csep10.phys.utk.edu/astr161/lect/retrograde/copernican.html
Computer programme : CABRI

 

 

 

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