Assignment 2: The Copernican Revolution

1473-1543 CE

Nicolaus Copernicus was not only a mathematician but also an astronomer. Although he graduated from university with a mathematics degree, he spent his life as a priest at a roman catholic church (Artymowicz, 2015). During his time, it was the Ptolemaic Model that astronomy was based on; the Earth was the center of the universe. Overtime, Copernicus became interested in astronomy due to his colleague and soon found himself exploring the universe's boundaries on his free time (Artymowicz, 2015). After reading many books on astronomy, Copernicus began to develop a celestial model of his own. However, he was skeptical about publishing his ideas at first because of the academia professors who would've rejected him (Artymowicz, 2015). Copernicus introduced numerous concepts and wanted to demonstrate his ideas using reasoning and evidence. He proves that (1) the Earth spins on it's axis and the stars in the distant remain motionless, (2) Earth being a planet orbits the Sun just like the other planets and therefore it is not located in the centre of the universe, and finally (3) the Sun does not orbit the Earth, but instead stays motionless in the centre of the solar system (Artymowicz, 2015).

Heliocentric Theory

  Among his famous theories was the theory of the heliocentric solar system. Copernicus' belief that uniform motion should only be performed by the planets led him to reject the Ptolemaic Model and insisted in the heliocentric model (Fitzpatrick, 2010). This theory was speculated and debated upon among other scientists before Copernicus. In order to prove this model, he observed that both Venus and Mercury were always in close approximation to the sun; they are never in opposition to the Sun (Fitzpatrick, 2010). Therefore, he claimed that both Venus and Mercury are closer to the Sun than the Earth is (Fitzpatrick, 2010). He concluded by stating that the Sun must be the center of the universe since it's the center of this motion (Fitzpatrick, 2010).

   
     Additionally, he observed retrograde motion which is the notion that the planet seemed to move in an opposite direction relative to other solar system bodies (Fitzpatrick, 2010). Copernicus explained that this was due to the fact that the Earth was moving faster along its orbit than the other planets were, and so from time to time it overtakes and passes the other planets (Maher,2009). This explained why the planet apparently moved in the opposite direction of the other bodies in the system. He also stated that the different planets were at different distances away from the sun due to the brightness at conjunctions and oppositions (Maher,2009).

     Another discovery he made that contributed to his model was that he claimed the Earth rotated on its own axis and his proof for this was based on his own observations (Maher,2009). He stated that the changes that one observes from the Earth are either due to movement of the observer or the object being observed (Maher,2009). Concluding that the observed changes were due to the Earth (object being observed), he also said that everything outside of the Earth contained an endless amount of substance and that these substances all moving along the same direction was impossible (Fitzpatrick, 2010). Another observation he made was that the Sun and the Moon both rise in the east and set in the west (Fitzpatrick, 2010). This showed a uniform movement of objects in the sky stating that the Earth was moving on its own axis.
     Finally, Copernicus stated that the Sun was motionless and in the center of the universe due to symmetry. The Sun which was located at the center of the universe created symmetry among the motion of the planets (Fitzpatrick, 2010). It made sense that the largest body the Sun, occupied motionless central space of the solar system, which also determined the periods of the planets relative to the sun.
     Even though Copernicus was fully credited for the heliocentric theory, Aristarchus as well as Pythagoras were the first to describe the Sun as being the center of the solar system, not the Earth (Maher, 2009). However, Copernicus was the first to create such a detailed model with justifications.

Scientists Before Copernicus
    Even though Copernicus created the Heliocentric model of the solar system, his ideas for this creation were based on astronomers of the past (Aristarchus, Heracleides, and Pythagoras). Pythagoras had stated that the Earth and Sun, along with other planets orbited a central structure called the "Central Fire" (Maher, 2009). He stated that the Earth would rotate around this central fire once every day. Through his observations he realized that the Sun and moon (stars) would rise and set throughout the day and therefore came up with the assumption that the Earth rotated on it's axis. Heracleides also believed that the Earth rotated on it's axis but thought that this occurred every twenty four house from a specific direction (west to east) (Fitzpatrick, 2010). Aristarchus on the other hand was the first to depict a model of the solar system where the Sun was in the centre and not the Earth, also stating that the Earth was in motion, orbiting around the Sun (Maher, 2009).

     The most important discovery made by Copernicus was that the Sun and not the Earth was the center of the solar system. This changed everything because it was widely accepted that the Earth was the center of the solar system. Using this, different observations were made about not only the Earth, but the other planets as well. This led to new discoveries about how the Earth differed from the other planets and what caused it to be unique and similar compared to them.

References

Artymowicz, P. (2015). The Origins of Modern Astronomy: The Copernican Revolution. Retrieved from http://planets.utsc.utoronto.ca/~pawel/ASTB03

Fitzpatrick,R. Copernicus's Model of the Solar System. (2010). Retrieved from http://farside.ph.utexas.edu/Books/Syntaxis/Almagest/node4.html

Maher,P. (2009). Copernicus on the Earth's Orbit Around the Sun. Retrieved from http://patrick.maher1.net/317/cope1.html

All pictures are from public domain.