Tuesday, 3 February 2015

Assignment 2: The Copernican Revolution


Assignment 2: The Copernican Revolution

By: Yarlesha Anantharajah

999839340


Nicolaus Copernicus was born on February 19, 1473 in Torun, Poland.  Copernicus developed his own celestial model of a heliocentric planetary system in Circa 1508.  Copernicus was given numerous titles such as diplomat (signed peace treaty), physician (advising dukes)
, economist (financial reform), classical scholar and translator, jurist Quadrilingual polyglot, astronomer, and lastly a mathematician.  Copernicus finally published his findings in 1514, about the Commentariolus. He had a second book published on the topic of De revolutionibus orbium coelestium, but the Roman Catholic Church not long following his death on May 24, 1543 in Frauenburg, Poland banned it.
Pythagoras was the first person known to have discovered and taught that the earth was spherical.  He was also the one to conclude that the earth traveled around the sun.  His founding was primarily based on the mystic viewpoint, not on astronomical grounds. It is believed that Copernicus adopted parts of Pythagorean worldview.  Pythagoras also produced the notion of the “Music of the spheres” which can be comprehended by the human mathematical mind.  However, although Copernicus did refer to the work of Pythagoras, he adapted physics to the demands of astronomy which was not included in Pythagoras’ work, believing that the principles of his system were incorrect, not the math or observations.  Copernicus was the first individual in history to create a complete and general system, combining mathematics, physics, and cosmology to his framework. 

Regarding Copernicus’ work and models, he believed that the Sun was the center of the universe while the earth rotated on its axis along with revolving around the Sun.  Copernicus started doubting Ptolemy’s geocentric model dating back to his college days.  He wrote a book named Commentariolus, also referred to as Little Commentary in which was a forty-page manuscript.

Copernicus also wrote another book titled De Revolutionibus Orbium Coelestium (On the Revolutions of Celestial Spheres). This book was essentially finished by about 1532.
In the Copernican model, the earth moves faster along its orbit, instead of the planets that lie further off from the Sun. However, it periodically overtakes and passes these planets, and thus the same thing happens as the Earth passes a planet such as Mars. Although Mars has a steady motion along its orbit, it seems to slow down to a stop and move westward in relation to the background stars as Earth passes it with the eastward motion in precisely the same path it followed earlier.  Copernicus’s model was very simple and easily comprehendible compared to the Ptolemaic model.  The Copernican hypothesis was gradually accepted, and has been given an alternative name called the Copernican Revolution.  This revolution was not just the adoption of a new idea but a total change in the way astronomers and the rest of humanity thought about the place of Earth.  
Unlike other astrologists, Copernican was never scared of showcasing his work, and he was surprisingly strongly encouraged by his Church to publish his results and methods, because it was believed to be useful for predicting planet positions also for Church purposes. 
 His ideas were further conversed in seminars being taught at Vatican. 

In the end I believe that his first finding that "the Earth is spinning around its axis every day, while the immense distant world of stars is motionless" is indeed true.  As the earth spins, the starts remain motionless, and it is all about perspective in the end.  Through his mathematics, he can measure the rotation of the planets, among the solar system proving that the stars indeed were motionless and it is just an illusion from the perspective from the earth. 
References 
http://www.biography.com/people/nicolaus-copernicus-9256984
http://scienceworld.wolfram.com/biography/Copernicus.html
Lecture 5/6 Slide


Tuesday, 20 January 2015

Assignment 1: Eratosthenes


            
                               

Eratosthenes was a well-known Ancient Greek Alexandrian scholar often referred to as the “father of geography” for his exceptional findings, specifically regarding the earth.  He was born in Cyrene, Libya around 276 B.C.E. Eratosthenes was most recognized in his work within the fields of astronomy, mathematics, history and philosophy.

Eratosthenes was initially a head librarian and scholar, and this is the era when Eratosthenes wrote a treatise about the world, called Geography. This is where the term geography originated.  Geography is a Greek term meaning "writing about the earth" in literal terms. His work Geography also introduced the climatic concepts of torrid, temperate, and frigid zones.  He created many reports from different travellers and explorers in order to describe the physical features of each region.  He described these regions through the action of natural phenomena such as water, fire, earthquakes and volcanic eruptions.

Eratosthenes was most notable for his determination of attempting to discover the circumference of the earth.  Being a Greek philosopher, he knew that the earth indeed was a sphere.  In order to calculate the circumference of the earth, Eratosthenes calculated the approximate distance between Syene and Alexandria by camel-powered trade caravans. Then, he measured the angle of the shadow in Alexandria on the solstice. He took the angle of the shadow (7°12') and divided it into the 360 degrees of a circle.  The equation was 360 divided by 7.2 yields.  He then multiplied the distance between Alexandria and Syene by 50 to determine the overall circumference.  Eratosthenes came to the conclusion that the circumference is 25,000 miles, which is only 100 miles over the actual circumference at the equator which is converted into 40,000 kilometres which is 250,000 stadia.
This diagram illustrates the cross-section of the Earth, at noon, on the northern hemisphere's summer solstice.  Eratosthenes used this information to calculate the circumference of the earth.

However, Eratosthenes’s calculations were not as accurate as he made it seem.  A Greek geographer named Posidonius believed that Eratosthenes' circumference was too large. He conducted a calculation of the circumference on his own, and ended up getting the result of 18,000 miles, which was 7,000 miles too short.

Eratosthenes also came up with his own method for charting the Earth’s surface. The way he categorized it was by separating the world known to him into a Northern and Southern division by using an east–west line parallel to the equator running through the island of Rhodes, and dividing the Mediterranean. He then added a second north–south line at right angles running through Alexandria. Eratosthenes also drew additional east–west as well as north–south lines to his map. 
This illustrates Eratosthenes’ method for calculating the circumference of the earth by by calculating the distance between these two points.  This allowed Eratosthenes to calculate the curvature of the earth between the two points and figure out how to apply the information to calculate the circumference of the earth.

References Used: