Group+2

Grace Guo, Chen Ting, Wang Anqi, Tay Weiling, Chua Ching Yee, Debra Jane Thio
 * Group 2 -- Seeing Stars: From Copernicus to Galileo**

A) TIMELINE OF MAJOR EVENTS IN DEVELOPMENT OF ASTROLOGY

 * **Year** || **Month/Date** || **Event** ||  ||
 * 1473 || February 19th |||| Nicolaus Copernicus was born. ||
 * 1514 ||  |||| Copernicus distributed a small handwritten copy of a book to a few of his friends. Known as “Little Commentary”, the book provided 7 axioms of his theory of the sun being the centre of the universe. ||
 * 1543 || Before May |||| Copernicus published “De Revolutionibus”, a book he had kept for so long before reluctantly publishing it on his deathbed. ||
 * 1543 || May 24th |||| Nicolaus Copernicus died. ||


 * **Year** || **Month/Da****te** || **Event** ||
 * 1546 || December 14th || Tycho Brahe was born. ||
 * 1572 || November 11th || He observed a a new star in Cassiopeia, now known as SN 1572. ||
 * 1573 ||  || His 1572 observations were published. ||
 * 1576 ||  || He sets up Uraniborg laboratory on the island of Hven, which was part of Denmark then. ||
 * 1587 ||  || He invented the geo-heliocentric model of the solar system, where the orbits of the Sun and Mars intersected. ||
 * 1601 || October 24th || Tycho Brahe died. ||


 * **Year** || **Month/Date** || **Event** ||
 * 1546 || February 15th || Galileo Galilei was born. ||
 * 1592 ||  || He moved to the University of Padua and taught mathematic, astronomy and mechanics. ||
 * 1601 ||  || He stopped teaching at the University of Padua. Then, he made significant discoveries in both pure science (for example, kinematics of motion, and astronomy) and applied science (for example, strength of materials, improvement of the telescope). ||
 * 1610 ||  || Galileo published an account of his telescopic observations of the moons of Jupiter, using this observation to argue in favour of the sun-centered, Copernican theory of the universe against the dominant earth-centered Ptolemaic and Aristotelian theories in //The Starry Messenger.// ||
 * 1612 ||  || Opposition arose to the Sun-centered theory of the universe which Galileo supported. ||
 * 1632 || October || Published //Dialogue Between the Two Chief World System// and was ordered to appear before the Holy Office in Rome where he underwent a papal trial in which he was found vehemently suspect of heresy ||
 * 1638 ||  || Smuggled //The Two New Sciences// out of Italy which was published in Protestant Holland ||


 * **Year** || **Month/Day** || **Event** ||
 * 1561 || January 22nd || Francis Bacon was born ||
 * 1620 ||  || //Novum Organum// was a philosophical work, a new system of logic which Bacon published. This was believed to be superior to the old ways of syllogism (logical arguments). ||
 * 1626 || April 9th || Francis Bacon died. Many of his works were published after his death. ||


 * **Year** || **Month/Date** || **Event** ||
 * 1571 || December 27 || Johannes Kepler was born. ||
 * 1602 ||  || Kepler’s refined his second law of planetary motion: //planets sweep out equal areas in equal times// ||
 * 1604 || October || Observation of supernova, now known as SN 1604. ||
 * 1609 ||  || Sets out his laws in Rudolphine Tables ||
 * 1630 || November 15 || Johannes Kepler died. ||


 * **Year** || **Month/Day** || **Event** ||
 * 1596 || March 31st || René Descartes was born ||
 * 1637 ||  || //Discourse on the Method// was published. In it, Descartes laid out four rules of thought, meant to ensure our knowledge rests upon a firm foundation. ||
 * 1650 || February 11th || René Descartes died ||

B) STAGES IN DEVELOPMENT IN ASTROLOGY FROM COPERNICUS TO GALILEO  The scientific revolution entailed three major changes: the emergence and confirmation of a heliocentric view of the universe, the development of a new physics that fit in such a view, and the establishment of a scientific method. The aspect of astronomy has seen remarkable changes and discoveries since early 1500s.

1. Astronomy before the scientific revolution  Before the scientific revolution, from the age of pharaohs to the 1500s, people believed that the sun, the stars and the planets moved around the earth as this can be supported by the common observations of philosophers and peasants alike who could watch the sun and the stars move from one horizon to another everyday. The two most important philosophers during the Middle Ages, Aristotle and Ptolemy, had also came up with explanations to this concept of the universe. Aristotle suggested that each being or substance sought to reach its ‘natural place’. The four fundamental elements were constantly trying to sort themselves out into those natural places on earth. While the ever-changing earth sat in the centre of the universe, the unchanging heavens moved in perfect circles around it. However, people have found problems with such a concept. In order to explain for these and other orbital irregularities, Ptolemy came up with sophisticated mathematical formulas which European astronomers doubted. By the early 16th century, the old Roman calendar was significantly out of alignment and there was a need to correct the calendar. Catholic authorities began to summon mathematicians and astronomers from all over Europe to solve this problem.

Nicholas Copernicus (1473-1543)



Copernicus’ Life  Copernicus was a Polish clergyman and a university astronomer who was one of the researchers who was summoned in order to find a solution to the problem. He studied at the University of Kraków, where he took up Latin, mathematics, astronomy, geography, and philosophy there. It was also there where he learnt about Aristotle and Ptolemy’s views about the universe, so as to equip himself with knowledge on how to understand the calendar, calculate the dates of holy days, and navigate at sea. However, as Copernicus was a very faithful Christian, he did not believe that God would create a universe as ramshackle and messy as Ptolemy’s, with its mathematical trickery and circles within circles. It was the urge to discover more about God and “God’s handiwork” that prompted him to research more about astronomy. Hence, his education at the university of Kraków could be said as a crucial factor for his achievements in astronomy.

On 19 October 1946, Copernicus moved on to the University of Bologna to acquire a degree in canon law. In addition to his official course in canon law, he also took up Greek, mathematics and astronomy. On 20 October 1497, while in Bologna, Copernicus received official notification of his appointment as a canon and of the comfortable income he would receive without having to return to carry out any duties. However, he did not complete his degree in canon law in Bologna as he visited Rome in 1500, which all Christians were encouraged to do to celebrate the great jubilee. Hence, he proposed to go to the university of Padua to take a law degree and study medicine. However, he did not disclose the other reason for his return to Italy - that of which to further his studies in astronomy.

In 1512, a few years after his return from Padua, Copernicus resumed his duties as a canon in the Ermland Chapter at Frauenburg. He devoted his time to his study of astronomy, having an observatory in the rooms in which he lived in one of the towers in the town's fortifications.

Copernicus’ Discoveries  Around 1514 he distributed a little hand-written book to a few of his friends who knew that he was the author, even though no author is named on the title page. The book was titled “Little Commentary”, providing seven axioms of his theory of the sun being the centre of the universe. They are:

• There is no one centre in the universe. • The Earth's centre is not the centre of the universe. • The centre of the universe is near the sun. <span style="background: yellow; color: #365f91; font-family: 'Arial','sans-serif'; font-size: 11pt; position: relative; top: 1pt;">• <span style="background: yellow; color: #365f91; font-family: 'Arial','sans-serif'; font-size: 11pt;">The distance from the Earth to the sun is imperceptible compared with the distance to the stars. <span style="background: yellow; color: #365f91; font-family: 'Arial','sans-serif'; font-size: 11pt; position: relative; top: 1pt;">• <span style="background: yellow; color: #365f91; font-family: 'Arial','sans-serif'; font-size: 11pt;">The rotation of the Earth accounts for the apparent daily rotation of the stars. <span style="background: yellow; color: #365f91; font-family: 'Arial','sans-serif'; font-size: 11pt; position: relative; top: 1pt;">• <span style="background: yellow; color: #365f91; font-family: 'Arial','sans-serif'; font-size: 11pt;">The apparent annual cycle of movements of the sun is caused by the Earth revolving round it. <span style="background: yellow; color: #365f91; font-family: 'Arial','sans-serif'; font-size: 11pt; position: relative; top: 1pt;">• <span style="background: yellow; color: #365f91; font-family: 'Arial','sans-serif'; font-size: 11pt;">The apparent retrograde motion of the planets is caused by the motion of the Earth from which one observes. <span style="color: #365f91; font-family: 'Arial','sans-serif'; font-size: 11pt;">

He was **one of the first few** who suggested the idea of a heliocentric universe, because he thought that it would offer a simpler and more accurate explanation. However, he still adopted a lot of Ptolemy’s ideas, such as epicycles, so his model was actually no more accurate than Ptolemy’s. However, it served its purpose as an intellectual springboard for a complete criticism of the then dominant view of the position of the earth in the universe.

He also wrote a book called “On the Revolutions of the Heavenly Spheres” (De revolutionibus), which offered an alternative model of the universe to Ptolemy's geocentric system, but hesitated a long time before finally deciding to publish it. The reason could once again be attributed to his extremely conservative attitude. As Rheticus, the publisher of the trigonomial sections of Copernicus’ book, commented on his progress by stating that he had “finally overcome his prolonged reluctance to release his volume for publication.” Copernicus only received the final copy of the book on his deathbed.

As Copernicus was an extremely conservative thinker and a faithful Christian, he did not see his work as a break either with the church or the ancient authorities. Instead, he wanted to believe that he had actually restored a pure understanding of God’s design, one that had been lost over the centuries. His Lutheran publisher had also added an introduction to serve as a disclaimer that the book was only for readings of interest and another set of mathematical tools for doing astronomy, not a dangerous claim about the nature of heaven and earth. Because of this, his ideas remained politically harmless and obscure for decades.

<span style="color: #e36c0a; font-family: 'Arial','sans-serif'; font-size: 11pt;">

**Significance of Copernicus’ Discoveries**
Copernicus is said to be the founder of modern astronomy.

Copernicus indeed played a major role in the aspect of astronomy during the Scientific Revolution. It went against the philosophical and religious beliefs that had been held during the medieval times. Man, it was believed (and still believed by some) was made by God in His image, man was the next thing to God, and, as such, superior, especially in his best part, his soul, to all creatures, indeed this part was not even part of the natural world (a philosophy which has proved disastrous to the earth's environment as any casual observer of the 20th century might confirm by simply looking about). Copernicus' theories might well lead men to think that they are simply part of nature and not superior to it and that ran counter to the theories of the politically powerful churchmen of the time. Therefore, by challenging the general belief at that time, Copernicus has taken man's first step to a new world of science.The most important aspect of Copernicus' work is that it forever changed the place of man in the cosmos; no longer could man legitimately think his significance greater than his fellow creatures; with Copernicus' work, man could now take his place among that which exists all about him, and not of necessity take that premier position which had been assigned immodestly to him by the theologians.

"//Of all discoveries and opinions, none may have exerted a greater effect on the human spirit than the doctrine of Copernicus. The world had scarcely become known as round and complete in itself when it was asked to waive the tremendous privilege of being the center of the universe. Never, perhaps, was a greater demand made on mankind - for by this admission so many things vanished in mist and smoke! What became of our Eden, our world of innocence, piety and poetry; the testimony of the senses; the conviction of a poetic - religious faith? No wonder his contemporaries did not wish to let all this go and offered every possible resistance to a doctrine which in its converts authorized and demanded a freedom of view and greatness of thought so far unknown, indeed not even dreamed of.//" [Goethe.]

<span style="color: red; font-family: 'Arial Bold','serif'; font-size: 11pt;">3) Tycho Brahe (1546- 1601)

<span style="font-family: 'Arial','sans-serif'; font-size: 11pt;">

<span style="color: fuchsia; font-family: 'Arial Bold','serif'; font-size: 11pt;">Brahe’s Life <span style="color: fuchsia; font-family: 'Arial','sans-serif'; font-size: 11pt;"> Another important astronomer after Copernicus was Tycho Brahe, a high ranking Danish nobleman who was trained as an astronomer when he was young. Tycho had a twin, but his twin died shortly after birth. Tycho's father was Otte Brahe, a Danish nobility and an important man among the Danish King's closest group of supporters. Hence, he groomed Tycho for a career at court, but from an early age he had shown a greater interest in astronomy than law.

When Tycho was two years old, his uncle took him away without the knowledge of his parents. Surprisingly, this unusual incident did not spark any disputes between his biological parents and his foster parents, Jorgen Brahe and his wife Inger Oxe. Like his father, his uncle Jorgen Brahe was also a Danish nobility and had little time for scholarly pursuits, while his foster mother, who had many scholarly interests like her family members, gave him most of the benefits of an education.

On 19 April 1559, Tycho began his studies at the University of Copenhagen. There, he studied law as well as a variety of other subjects, and became interested in astronomy. It was, however, the eclipse which occurred on 21 August 1560, particularly the fact that it had been predicted, that impressed him so much that he began to make his own studies of astronomy helped by some of the professors.

<span style="color: #365f91; font-family: 'Arial Bold','serif'; font-size: 11pt;">Brahe’s Discoveries <span style="color: #365f91; font-family: 'Arial','sans-serif'; font-size: 11pt;"> In 1562, he set off for the University of Leipzig. There, he began making observations, and by August 1563, he started recording them. The second observation he recorded was a conjunction of Jupiter and Saturn. However, as he compared them to the tables based on Copernicus and Ptolemy, he found out that neither gave the correct date for the conjunction. Ptolemy's was out by nearly a month and even Copernicus’ was out by days. Upon discovering this, Tycho was confident that he could come up with a better table. Hence, this was a significant moment for his achievements as it sparked off his full-time research.

Tycho then studied astronomy with Bartholomew Schultz at Leipzig who taught him how to obtain more accurate observations. One of the way is getting good instruments, hence Tycho acquired them immediately. In 1566 he set off for the University in Wittenburg, and then that in Rostock. While in Rostock, he lost part of his nose in a duel with another Danish student, and had it replaced with an artificial nose made of gold and silver. Its significance was that Tycho developed an interest in medicine and alchemy because of this incident.

=
In 1572 Tycho observed the new star in Cassiopeia and published a brief tract about it the following year. In 1574 he gave a course of lectures on astronomy at the University of Copenhagen. He set off on another trip abroad in 1574, visiting an observatory that Landgraf Wilhem IV of Hessen-Kassel had founded at Kassel about 15 years earlier. Tycho was very impressed by the methods used there. Afterwards, the observatory that he built was somewhat influenced by what he has seen here in Kassel.======

Returning to Denmark in 1575, he decided to settle in Basel after he left, but King Frederick of Denmark wanted his most distinguised scientist to stay, so he offered Tycho the island of Hven (called today Ven) -

With financial help from the King of Denmark, he went on to set up a purpose-built observatory, on the island of Hven in Copenhagen Sound. The observatory, called Uraniborg, was equipped with exceptionally large and accurate instruments (and with an alchemical laboratory in its basement) and thus, became the finest observatory in Europe. At his new observatory, Tycho made many new instruments that further aided him to study astronomy in greater detail. In 1584, when the Uraniborg was too small to store all his instruments, he built a new one called the Stjerneborg. This was the year in which he was most active in producing new instruments.

At his time at the observatory, he had collected the finest set of astronomical data ever seen. Using his data, Tycho came up with a theory that proved enormously successful at his time: that the Earth was stationary, and the Moon and the Sun revolved around the Earth; other planets, however, revolved around the sun. Although Tycho was convinced by Copernicus’ heliocentric model in his younger days, he could not bring himself to accept it completely. This is because, unless the Earth was in the centre of the universe, the scale of the universe would be incredibly and unreasonably large. However, after years of research, today we now know that the scale of the universe <span style="color: #365f91; font-family: 'Arial Italic','serif'; font-size: 11pt;">is <span style="color: #365f91; font-family: 'Arial','sans-serif'; font-size: 11pt;"> incredibly large, with the Sun being in the centre. Tycho’s theory had been very successful because it allowed accurate astronomical and astrological predictions to be made more easily than in the old Ptolemaic system, and it avoided upsetting theological implications of the Copernican system.

However, Tycho closed down his observatory in 1597 after falling out with King Christian. He moved to Denmark with his family in search of support for him to continue his observatory works. In 1599 he was appointed Imperial Mathematician to the Holy Roman Emperor, Rudolph II, in Prague (then the capital of the Holy Roman Empire). Johannes Kepler joined him as an assistant, to help with mathematical calculations. Tycho wanted to prove his theory right through the observations done. Kepler joining him was significant since he would continue on Tycho’s observations after he died.

==== Brahe not only designed and built instruments, he also calibrated them and checked their accuracy periodically. He thus revolutionized astronomical instrumentation. Brahe’s work in developing astronomical instruments and in measuring and fixing the positions of stars paved the way for future discoveries. He also changed observational practice profoundly. Whereas earlier astronomers had been content to observe the positions of planets and the Moon at certain important points of their orbits, Tycho and his cast of assistants observed these bodies throughout their orbits. As a result, a number of orbital anomalies never before noticed were made explicit by Tycho. Without these complete series of observations of unprecedented accuracy, Kepler could not have discovered that planets move in elliptical orbits. Tycho was also the first astronomer to make corrections for [|atmospheric refraction]. In general, whereas previous astronomers made observations accurate to perhaps 15 arc minutes, those of Tycho were accurate to perhaps 2 arc minutes, and it has been shown that his best observations were accurate to about half an arc minute. ====
 * <span style="color: #e36c0a; font-family: 'Arial','sans-serif'; font-size: 11pt;">Significance of Brahe's Discoveries **

<span style="color: red; font-family: 'Arial Bold','serif'; font-size: 11pt;">4) Galileo Galilei (1564 - 1642) <span style="font-family: 'Arial','sans-serif'; font-size: 14pt;"> <span style="-webkit-border-horizontal-spacing: 2px; -webkit-border-vertical-spacing: 2px; -webkit-text-decorations-in-effect: none; border-collapse: collapse; font-family: arial,sans-serif; font-size: medium; font-weight: normal; line-height: normal; white-space: nowrap;"> <span style="color: fuchsia; font-family: 'Arial','sans-serif'; font-size: 11pt;">Galileo was an Italian, and during his lifetime, a physicist, an astronomer, a mathematician and a philosopher all at once. He could also be said as one of the people who played a major role in the Scientific Revolution.
 * <span style="color: fuchsia; font-family: 'Arial','sans-serif'; font-size: 11pt;">Galileo’s Life **

Galileo was the first child of Vincenzo Galilei and Guilia Ammannati. His father, Vincenzo, was a music teacher and a fine lute player. His parents married in 1563 and they made their home in a countryside near Pisa. In 1572, when Galileo was eight years old, his family returned to Florence, his father's home town. However, Galileo remained in Pisa and lived for two years. When he was ten, Galileo left Pisa to join his family in Florence where he was tutored by Jacopo Borghini. Once he was old enough to be educated in a monastery, his parents sent him to the Camaldolese Monastery at Vallombrosa which is situated on a magnificent forested hillside 33 km southeast of Florence. Galileo’s father was not pleased with Galileo wanting to join the Camaldolese Order, so he made him return back to Florence.

In 1581, Vincenzo sent Galileo back to Pisa to enrol for a medical degree at the University of Pisa. Although Galileo never wanted to enter a medical career, his father's wish was a fairly natural one since there had been a distinguished physician in his family in the previous century. Instead, Galileo did not seem to have taken medical studies seriously. He attended courses on his real interests which were in mathematics and natural philosophy. His mathematics teacher at Pisa was Filippo Fantoni, who held the chair of mathematics. Galileo returned to Florence for the summer vacations and continued to study mathematics there.

During the summer of 1583 when Galileo was back in Florence with his family, Vincenzo encouraged him to further his medical studies. However Galileo, still reluctant to study medicine, invited Ostilio Ricci, who taught Galileo a course on Euclid's Elements in the University of Padua, home to meet his father. Ricci tried to persuade Vincenzo to allow his son to study mathematics since he was interested in it. Certainly Vincenzo did not like the idea and resisted strongly but eventually, he gave way a little. Of course Galileo was still officially enrolled as a medical student at Pisa but eventually, by 1585, he gave up this course and left without completing his degree.

In 1591, Galileo's father died and since Galileo was the eldest son, he had to provide financial support for the rest of the family. However, he was not well paid as a professor of mathematics at Pisa so Galileo looked for a more lucrative post. In 1952, Galileo was appointed professor of mathematics at the University of Padua at a salary of three times of what he had received at Pisa. He mainly taught medical students Euclid's geometry and standard (geocentric) astronomy, since they would need to know some astronomy in order to make use of astrology in their medical practice. However, Galileo argued against Aristotle's view of astronomy and natural philosophy in three public lectures he gave in 1604. In a personal letter written to Kepler in 1598, Galileo had stated that he was a Copernican. However, no public sign of this belief was to appear until many years later.

In May 1609, Galileo received a letter from Paolo Sarpi telling him about a spyglass that a Dutchman had shown in Venice. Using his technical skills as a mathematician and as a craftsman, Galileo began to make a series of telescopes whose optical performance was much better than that of the Dutch instrument. While most people believe that it was Galileo who had invented the telescope, this is not true. He merely made improvements on the existing model so that it was able to see much further than before.
 * Galileo’s Discoveries **<span style="color: #365f91; font-family: 'Arial','sans-serif'; font-size: 11pt;">

When Galileo pointed the telescope at the sky, he observed many things: <span style="background: yellow; color: #365f91; font-family: 'Arial','sans-serif'; font-size: 11pt;">1. He discovered the Moon was smooth as everyone thought it out to be. It was rough and uneven. 2. Discovered four moons revolving around Jupiter 3. Found out that there are actually many many more stars than visible to the naked eyes 4. Discovered puzzling appearance of Saturn (which was later shown to be a ring surrounding it) 5. That Venus goes through phases just like the Moon does.

<span style="color: #365f91; font-family: 'Arial','sans-serif'; font-size: 11pt;">Galileo’s observations supported Copernicus’s theories of the Universe, and we now know them to be true, but back in his time, the Church held immense power, and these observations went against many of their beliefs that the Universe God had created was perfect and that the Earth was at the center of the Universe (Geocentric view). Hence, they would not even look through the telescope, as they felt that it was wrong to doubt what was in the heavens. Even if they did look through the telescope, it was hard to make them see what Galileo had observed, as it takes a trained eye in order to spot the observations. Therefore, it was not easy to make them believe in his theories.

Many other Astronomers and Philosophers also supported the Aristotelian view of the Universe, and did not subscribe to the Heliocentric view of the Universe which Galileo had proposed and openly supported.

When he began to publicly support heliocentrism, he was met with great opposition by the Church as well as by Philosophers. While in the beginning he was cleared of any offense, and Heliocentrism was denounced as ‘false and contrary to scripture’, he had to promise to abandon his support of this view. When he later defended himself by publishing the book <span style="color: #365f91; font-family: 'Arial Italic','serif'; font-size: 11pt;">Dialogue Concerning the Two Chief World Systems <span style="color: #365f91; font-family: 'Arial','sans-serif'; font-size: 11pt;"> in 1632 <span style="color: #365f91; font-family: 'Arial Italic','serif'; font-size: 11pt;">, <span style="color: #365f91; font-family: 'Arial','sans-serif'; font-size: 11pt;"> he was tried by the Roman Inquisition, found of heresy and placed under house arrest for the rest of his life. He was to be banned from working on or discussing Copernicus’ ideas. However, he continued to refine his ideas about the problems of motion. In 1638, Galileo smuggled <span style="color: #365f91; font-family: 'Arial Italic','serif'; font-size: 11pt;">The Two New Sciences <span style="color: #365f91; font-family: 'Arial','sans-serif'; font-size: 11pt;"> out of Italy which he published in Protestant Holland. Galileo then died in early 1642.

Galileo’s observations and much of his life work was dedicated to the proof of the Copernican system. His observations, such as the presence of sunspots and the craters on the moon, disproved the then popular Aristotelian theory that the Universe was perfect. His discovery of four satellites around Jupiter also proved that not everything in the Universe revolved around the earth. This gave birth to the Heliocentric world view.

<span style="color: #365f91; font-family: 'Arial Bold','serif'; font-size: 11pt;">Summary of Galileo <span style="color: #365f91; font-family: 'Arial','sans-serif'; font-size: 11pt;">

• He is known as the father of modern observational astronomy • Known for improvements to the telescope and consequent astronomical observations, and support for Copernicanism • He became truly famous with his improvement of the telescope. It started off with him hearing about this instrument from the Netherlands which showed distant things as if they were near. • He then quickly discovered the secret behind this instrument, made his own three-powered spyglass from lenses for sale in spectacle makers' shops. • He taught himself the art of lens grinding, and produced increasingly powerful telescopes. Eventually, he presented an eight-powered telescope. • He used it to observe the heavens with a magnification of up to 20 times.

** <span style="font-family: Arial,sans-serif;">
 * <span style="color: #e36c0a; font-family: 'Arial Bold','serif'; font-size: 11pt;">Significance of **** Galileo’s Discoveries

=
Galileo's most valuable scientific contribution was his founding of physics on precise measurements rather than on metaphysical principles and formal logic. More widely influential, however, were The Starry Messenger and the Dialogue,which opened new vistas in astronomy. Galileo's lifelong struggle to free scientific inquiry from restriction by philosophical and theological interference stands beyond science.======

<span style="color: red; font-family: 'Arial Bold','serif'; font-size: 11pt;">5) Johannes Kepler (1571-1630) <span style="font-family: 'Arial','sans-serif'; font-size: 11pt; letter-spacing: 0px;">

<span style="color: fuchsia; font-family: Arial,sans-serif; font-size: 11pt;">__J__ <span style="color: fuchsia; font-family: 'Arial','sans-serif'; font-size: 11pt;">ohannes Kepler was a mathematician who came from a troubled family. His father was a mercenary soldier, who died during a battle in the Netherlands when he was five. His mother was a daughter of an innkeeper. When Kepler was young, he used to help out at the inn, and his customers were surprised by his unusual arithmetic ability at his young age.
 * <span style="color: fuchsia; font-family: 'Arial','sans-serif'; font-size: 11pt;">Kepler’s Life **

Kepler is a highly religious man, as seen from all his writings containing numerous references to God. It is also probably his faithfulness towards his religion that prompted him to start studying about astronomy, and he saw his work as a fulfillment of his Christian duty to understand the works of God.

Kepler enrolled himself at the University of Tübingen. There, he studied mathematics, Greek, Hebrew and other courses. His teacher, Mästlin, was the one who chose to teach him more advanced astronomy by introducing him to the heliocentric cosmological system of Copernicus. This has led to him accepting the Copernican theory immediately. This is because he believes that the Copernican theory can explain more things more accurately than the geocentric astronomy. In geocentric astronomy, the planetary orbs were assumed to be in contact, so was impossible to use observations to find the relative sizes of the planetary orbs.

<span style="color: #365f91; font-family: 'Arial','sans-serif'; font-size: 11pt;">However, in the Copernican system, it was possible to use observations to calculate the size of each planetary orb, because the annual component of each planetary motion was a reflection of the annual motion of the Earth. It turned out that there were huge spaces in between the planets.
 * <span style="color: #365f91; font-family: 'Arial','sans-serif'; font-size: 11pt;">Kepler’s Discoveries **

In 1596, Kepler invented his first cosmological model, which not only explains the number of planets in the universe perfectly, but also gives a convincing fit with the sizes of the paths as deduced by Copernicus, the greatest error being less than 10%. He had hoped that his cosmological model can help prove that the Copernican theory is a better representation of the universe.

Kepler had hoped that better astronomical data and observations would help in his proving the Copernican theory true, so he sent a copy of his Mysterium cosmographicum to Tycho. In fact, Tycho was already working in Prague at that time, and had written to Mästlin in search of a mathematical assistant, so Kepler got the job. After Tycho’s death in 1601, Kepler succeeded him as Imperial Mathematician.

Kepler made good use of Tycho’s massive recorded observations to try to prove that Copernicus’ heliocentric universe theory was correct. He also liked to make use of mathematics to do his work and prove his theories. Hence, he was delighted when he came across Napier’s works on logarithms. However, at that time, many people did not trust logarithms, as few could understand how it works. Hence, Kepler made use of Tycho’s numerous data as well as his first and second laws to prove how logarithms work - it was based on a respectable source called the Euclid's Elements Book 5. His “Rudolphine Tables” proved enormously successful, and was still accurate even after decades. Having correctly proved the logarithms show that his proof on the Copernican theory is correct.

Kepler’s time in the Prague proved to be the most productive as it is where he established his three laws. His first law states that the earth and other planets travel in elliptical paths around the sun. His second law replaced Copernicus’s belief in uniform planetary velocity, that the speed of planets varies with their distance away from the sun. His third law states that the square of a planet’s revolution is proportional to the cube of its average distance from the sun, which means that planets with large orbits revolve at a slower average velocity than those with smaller orbits.

Kepler also wanted to prove that it was the magnetic attractions between the sun and the planets that keep the planets in orbital motion. Unfortunately, the mechanistic scientists in the seventeenth-century rejected his approach as they considered it “too magical”.

<span style="color: fuchsia; font-family: 'Arial','sans-serif'; font-size: 11pt;">Sadly, things went badly for Kepler in 1611. Firstly, Kepler’s seven-year-old son as well as his wife and true love, Babara, died. Next, the Emperor Rudolf, whose health was failing, was forced to abdicate in favour of his brother Matthias. Although Mathias was a Catholic like Rudolph, but he was intolerant of the Protestants. This led to Kepler having no choice but to leave Prague for Linz (now Australia). He remarried again, this time to Susanna. It was rumoured that he married his second wife just to have her look after his children. Kepler died in Regensburg after a short illness. He was buried in the local church, but it was destroyed in the course of the Thirty Years' War and nothing remains of the tomb.


 * <span style="color: #365f91; font-family: 'Arial','sans-serif'; font-size: 11pt;">Summary of Kepler’s Discoveries

First to correctly explain planetary motion, thereby, becoming founder of celestial mechanics and the first "natural laws" in the modern sense; being universal, verifiable, precise. ** <span style="color: #365f91; font-family: 'Arial','sans-serif'; font-size: 11pt;"> In Johannes Kepler's book "Astronomia Pars Optica", for which he earned the title of founder of modern optics he was the:
 * 1) First to investigate the formation of pictures with a pin hole camera;


 * 1) First to explain the process of vision by refraction within the eye;


 * 1) First to formulate eyeglass designing for nearsightedness and farsightedness;


 * 1) First to explain the use of both eyes for depth perception.

In Johannes Kepler's book "Dioptrice" (a term coined by Kepler and still used today) he was the:
 * 1) First to describe: real, virtual, upright and inverted images and magnification;


 * 1) First to explain the principles of how a telescope works;


 * 1) First to discover and describe the properties of total internal reflection.

In addition:
 * 1) His book "Stereometrica Doliorum" formed the basis of integral calculus.


 * 1) First to explain that the tides are caused by the Moon (Galileo reproved him for this).


 * 1) Tried to use stellar parallax caused by the Earth's orbit to measure the distance to the stars; the same principle as depth perception. Today this branch of research is called astrometry.


 * 1) First to suggest that the Sun rotates about its axis in "Astronomia Nova"


 * 1) First to derive the birth year of Christ, that is now universally accepted.


 * 1) First to derive logarithms purely based on mathematics, independent of Napier's tables published in 1614.


 * 1) He coined the word "satellite" in his pamphlet "Narratio de Observatis a se quatuor Iovis sattelitibus erronibus"

<span style="color: #e36c0a; font-family: 'Arial','sans-serif'; font-size: 11pt;">Among Kepler’s many other achievements, he provided a new and correct account of how vision occurs; he developed a novel explanation for the behaviour of light in the newly invented telescope; he discovered several new, semiregular polyhedrons; and he offered a new theoretical foundation for astrology while at the same time restricting the domain in which its predictions could be considered reliable. A list of his discoveries, however, fails to convey the fact that they constituted for Kepler part of a common edifice of knowledge. The matrix of theological, astrological, and physical ideas from which Kepler’s scientific achievements emerged is unusual and fascinating in its own right. Yet, because of the highly original nature of Kepler’s discoveries, it requires an act of intellectual empathy for moderns to understand how such lasting results could have evolved from such an apparently unlikely complex of ideas. Although Kepler’s scientific work was centred first and foremost on astronomy, that subject as then understood—the study of the motions of the heavenly bodies—was classified as part of a wider subject of investigation called “the science of the stars.” The science of the stars was regarded as a mixed science consisting of a mathematical and a physical component and bearing a kinship to other like disciplines, such as music (the study of ratios of tones) and optics (the study of light). It also was subdivided into theoretical and practical categories. Besides the theory of heavenly motions, one had the practical construction of planetary tables and instruments; similarly, the theoretical principles of astrology had a corresponding practical part that dealt with the making of annual astrological forecasts about individuals, cities, the human body, and the weather. Within this framework, Kepler made astronomy an integral part of natural philosophy, but he did so in an unprecedented way—in the process, making unique contributions to astronomy as well as to all its auxiliary disciplines.
 * <span style="color: #e36c0a; font-family: 'Arial','sans-serif'; font-size: 11pt;">Significance of Kepler’s Discoveries **

<span style="font-family: 'Arial Bold','serif'; font-size: 11pt;">6) Enrichment: Isaac Newton (1642-1727) <span style="font-family: 'Arial','sans-serif'; font-size: 11pt;">

During his lifetime, Newton worked on various subject matters, and amongst which, he was a physicist, an astronomer and a mathematician. He is said to be one of the people who made the greatest contributions to mankind, as well as advancing the Scientific Revolution <span style="font-family: Arial,sans-serif; font-size: 11pt;">__Contributions__ <span style="font-family: 'Arial','sans-serif'; font-size: 11pt;">

The “apple story” is well-known by everyone, as Sir Isaac Newton discovered the presence of Gravity which influenced the motions of objects on earth and that of celestial bodies after watching an apple fall from a tree.

. The three laws of motion: 2. Acceleration is produced when a force acts on a mass. The greater the mass (of the object being accelerated) the greater the amount of force needed (to accelerate the object). 3. For every action there is an equal and opposite re-action. . Light was made up of seven different colors
 * <span style="font-family: 'Arial','sans-serif'; font-size: 11pt;">1. **<span style="font-family: 'Arial Bold','serif'; font-size: 11pt;">A <span style="font-family: 'Arial','sans-serif'; font-size: 11pt;">n object at rest will remain at rest unless acted on by an unbalanced force. An object in motion continues in motion with the same speed and in the same direction unless acted upon by an unbalanced force. This law is often called "the law of inertia".

<span style="font-family: Arial,sans-serif; font-size: 11pt;">__Implications…__ <span style="font-family: 'Arial','sans-serif'; font-size: 11pt;">

His laws of Gravity demonstrated a consistency with Kepler’s laws of planetary motion, thus removing the last doubts about Heliocentrism. He was able to prove mathematically that all the planets were in free fall around the sun, and that these celestial bodies behaved similarly to the way objects on earth do (the fall straight down).

<span style="font-family: Arial,sans-serif; font-size: 11pt;">__The Reactions…__ <span style="font-family: 'Arial','sans-serif'; font-size: 11pt;">

Because Newton lived in the later period of the Scientific Revolution, by then, people were greatly more receptive of new ideas than in Galileo’s time (Newton was born the year Galileo died). They were more ready to believe that Gravity existed than in Galileo’s Heliocentric world view, as seen from various societies such as the Royal Society established to facilitate the spread of science. Also, Newton had been able to support his theory with mathematical proof, while Galileo only had his observations through the telescope to go by.

Another possible reason the reaction to Newton was significantly lesser than to Galileo was that although unorthodox, he was a highly religious man. He had sought to use Mathematics to explain the work of God, instead of trying to disprove the theories of the perfect Universe. As such, the church reacted less violently to his theories than they did to Galileo.

C) BIBLIOGRAPHY

 * =====Western Civilisations (Volume 2) by Judith G. Coffin, Robert E. Lerner, Robert C. Stacey, Standish Meacham, published by W.W. Norton & Company Inc. in USA in 2002=====
 * ===== http://www-history.mcs.st-and.ac.uk/Biographies/Copernicus.html =====
 * ===== http://www-history.mcs.st-and.ac.uk/Biographies/Brahe.htm[|l] =====
 * ===== http://www.hps.cam.ac.uk/starry/tycho.html =====
 * ===== http://www-history.mcs.st-and.ac.uk/Biographies/Kepler.html =====
 * ===== http://en.wikipedia.org/wiki/Galileo_Galilei =====
 * ===== http://en.wikipedia.org/wiki/Isaac_Newton =====
 * ===== http://galileo.rice.edu/sci/kepler.html =====
 * ===== http://www-history.mcs.st-and.ac.uk/Biographies/Galileo.html =====
 * =====Galileo Galilei: Inventor, Astronomer and Rebel by Michael White=====
 * =====The Cambridge Companion to Galileo by Peter K. Machamer=====
 * =====The Day the Universe Changed by James Burke=====
 * =====http://en.wikipedia.org/wiki/Tycho_Brahe=====
 * =====http://en.wikipedia.org/wiki/Copernicus=====
 * =====http://en.wikipedia.org/wiki/Galileo_galilei=====
 * =====http://en.wikipedia.org/wiki/Johannes_Kepler=====
 * =====http://en.wikipedia.org/wiki/René_Descartes=====
 * http://en.wikipedia.org/wiki/Francis_Bacon
 * RGS History Notes 2010
 * http://cnx.org/content/m13245/latest/
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