The sun-centered model 3

1 Copernicus

Copernicus was the first convincing supporter of the sun-centered model since Aristarcus.

He was a versatile figure because he also proposed a currency reform policy, and translated

Greek poems. However his passion was astronomy , his ideas would eventually shake the

astronomy world. To be surprised, his mere twenty pages of work on astronomy was not

formally published, so his vast contribution to astronomical knowledge hadn¡Çt been

appreciated so widely. He supported the sun-centered model based on three axioms below.

   1 The heavenly bodies don¡Çt share a common center.
   2 The earth isn¡Çt the center and the sun is near the center.
   3 The daily motion of the stars results from the Earth¡Çs rotation on its own axis.
                                                                                   

He succeeded to predict the orbits of Mars, but it wasn¡Çt enough to defeat the

sun-centered model which had been being improved for almost 1000 years. Unfortunately,

his model was recognized as a convenient way for calculating the planets¡Ç orbit at that time

by the pro sun-centered model astronomers. As a result his theory went to hibernation for

30 years.

2 Tyco Brahe and Kepler

Tyco Brahe was famous as a good observer rather than an astronomer. It is said that he

lost a part of his nose in a duel, so he could see further without his view being blocked by his

nose. He was a chief of the observatory Uraniborg which had modern equipment. His

observation forced him to suspect the validity of the earth-centered model, he invented a

weird model which was never accepted. ¢¨£± He was not a good enough calculator to know

what his accumulated information meant. However, he had a great partner, Kepler who

championed the sun-centered model based his observation data in 1650. Though Kepler

suffered from myopia, he was good at calculating, so they were the best partners.

As he calculated the orbit of Mars, he realized flaws in the Copernicus¡Çs sun-centered

model: His assumptions that the earth moves in perfect circle, the orbit speed is always

same, the sun is the center of orbits. After setting aside all of assumptions, he concluded

as follows.

­¡ The planets move in elliptical circles.
­¢ The planets continuously vary their speed.
­£ The sun is not the center of orbits.
                                         

It took almost eight years to prove that the sun-centered model was right after his

conclusion. His 900 page-work was devoted to only calculations, so he asked readers to be

patient, and his work wasn¡Çt widely accepted. But at least he managed to prove the validity

of the sun-centered model scientifically.

3 Galileo

Galileo was so inventive that he never hesitated to criticize authority. He improved the

rudimental telescope for commercial purposes. He profited from this and realized its

potential for scientific value. He could make many momentous observations with it.

For example, he first discovered that four moons orbited around Jupiter. Ptolemy assumed

that all planets revolved around the Earth, but he was proved to be wrong.

Furthermore, his observation of the phases of Venus disproved the sun-centered model.¢¨3

The sun-centered model was supported not only by the calculations but also by concrete

proof. However the shift from the earth-centered model to the sun-centered model didn¡Çt take

place so quickly. Especially, the Catholic Church was unwilling to abandon its doctrine that

the earth was centered in the universe and many jealous astronomers to Galileo¡Çs fame

stirred up problems, so Galileo was isolated from the astronomical circles and was filed a

sue against his opinion which contradicted the Christian doctrine. To make matters worse, his

strong supporter Pope Urban ­¼ changed his pro Galileo policy suddenly. They were close

friends and attended the same university in Pisa, but the newly elected Pope bent his faith

by strong lobbing. However, Galileo wasn¡Çt sentenced the death penalty, because Pope

secretly asked inquiries not to be strict to Galileo. After the trial, he suffered from eye

diseases that resulted from long observation and eventually became almost blind.

Afterwords

¡¦I¡Çm looking at Beijin city from a satellite with writing this article. I can see any side

of the earth from the universe, because of the map soft Google Earth. Though I know that the

earth orbits around the sun, it is still amazing for me. Could ancient astronomers imagine

the blue sphere is spinning in the blackened space? Did they have any perspective that

the earth was tilted by the gravity of the moon? I¡Çm very impressed at their imagination

that enabled them to think the sun-centered model without any observation device like

Google Earth. It is difficult for us to believ