Astronomy+Discoveries+and+Significant+Figures

=__Timeline of Astronomy Events related to Scientific Revolution__ By Arathi Vinod, Candace Yeo, Claire Chia, Michelle Wang, Nurul Amirah and Sheryl Chng. =

4th Century BC - Aristotle and Plato write on the Geocentric theories. 147 AD - "Almagest", a book by Ptolemy based on his Geocentric views, is widely accepted by the public.
 * Aristotle and Plato (Geocentric, Earth-centred views)**

1497 AD - Copernicus starts questioning Ptolemy's theories. 1530 AD - Copernicus starts circulating a manuscript, with an outline of his ideas on a heliocentric model. However, he fails to reject Aristotle's widely accepted Geocentric views as he did not dare to aggravate the Catholic church (who also accepted Aristotle's views). The Catholic Church had boundless amounts of power to control the people's thinking and would often charge people who opposed conventional Scientific theories for heresy. 1543 AD - Only nearing his death, Copernicus' manuscript is officially published as a book known as "On the Revolutions of the Heavenly Spheres". However, his theory still states that planets move in a circular motion which will be disproved.
 * Nicolas Copernicus (Heliocentric, Sun-centred views)**

1572 AD - Brahe spots a supernova. 1577 AD - Brahe and Johannes Kepler meet in Prague, as guests of King Rudolf II. 1576-1597 AD - Brahe spends 20 years observing the sky each night, collecting a humongous set of data. This data disproved Aristotle's and Ptolemy's Geocentric theories, yet he refused to accept Copernicus' views. He then came up with the Tychonic system, where planets revolved the sun while the sun and moon revolved around the Earth. 1601 AD - Brahe passes away, leaving his instruments to Kepler.
 * Tycho Brahe (Tychonic views)**

1602-1603 AD - Kepler edits and publishes Brahe’s work Astronomiae instauratae progymnasmata, 'Beginnings of a New Astronomy', having the precise location of 777 stars. 1609 AD - Kepler, using Brahe's information and his own observations, publishes "The New Astronomy". This book contains his findings that planets move in elliptical, not circular, orbits. He also proves that planets sweep out equal areas in equal intervals of time and that there was a direct proportion between the size of an orbit and the amount of time a planetary body took to orbit around the sun.
 * Johannes Kepler (Heliocentric views)**

1609 AD - After hearing of the new invention, the telescope, Galileo decides to improve on it. Within a year, it can magnify up to 33 times.
 * Galileo Galilei (Heliocentric views)**

1610 AD - Using his telescope, magnifying Jupiter, Galileo sees four moons circling it. By Ptolemy’s theory, this would have caused Jupiter to shatter. He also saw spots on the Sun, which implied that the Sun too is revolving. he publishes a brief account of his observations in a book, Siderus Nuncius (The Starry Messenger). It was well received and he was brought to immediate fame. 1613 AD - Galileo publishes the “Istoria e dimostrazioni intorno alle machie solari”, Account and Evidence of the Sun spots, which is a direct contradiction to Ptolemy’s theory, proving the Copernican theory right. This book creates much unrest within the Catholic Church and under its influence he faces house arrest for a few years. 1623 AD - A new pope, Urban VIII allows Galileo to compare the Ptolemaic and Copernican theories. However, this was just meant to be a comparison, and no conclusion was to be reached of the truth of either theory. 1632 AD - Galileo publishes his masterpiece, Dialogo sopra i due massimi sistemi del mondo (Dialogue on the two chief world systems) However, the last chapter makes an obvious conclusion on the truth of the two theories, enraging Urban VIII. 1633 AD - Galileo is convicted of having held the the Copernican heresy, and he is tortured and sentenced to life imprisonment.

=__Figures who contributed to the astronomical field of the Scientific Revolution__=

__**Nicolaus Copernicus**__

Background: Nicolaus Copernicus (1473-1543) was born into a relatively wealthy family and never married. He received education in the Kraków Academy, which had areas specializing in the area of astronomy and mathematics, and this lead him to seriously question Aristotle's and Ptolemy's geocentric views.

Contributions: He was the first astronomer to concoct a heliocentric cosmology that displaced the Earth from the center of the universe. Nicolaus Copernicus’ epochal book, "De Revolutionibus Orbium Coelestium" - [|On the Revolutions of the Celestial Spheres] - is often regarded as the starting point of modern astronomy and the defining epiphany that began the Scientific Revolution. Copernicus proposed that the planets have the Sun as the fixed point and they revolve around it, this theory is also known as the heliocentric concept. The Earth, besides orbiting the Sun annually, also rotates slowly once daily on its own axis. He also claimed that the universe made up of eight planets that revolved around the sun in order of Mercury, Venus, Earth, Mars, Jupiter and Saturn. The moon revolved around the Earth only. Copernicus's theory had significant contributions for later thinkers of the scientific revolution, including such major figures as Galileo, Kepler, Descartes, and Newton.

__**Tycho Brahe**__

Background: At age 12, Tycho (1546-1601) enrolled in the University of Copenhagen and studied law, to please his uncle who had raised him. Aside from law, Tycho also studied several subjects, and that was when he first got interested in astronomy. After predictions about the solar eclipse that occured on the 21st of August 1560 came to be true, Tycho was so impressed that he began his own studies on astronomy. Every night, Tycho would observe the stars systematically using the most accurate instruments available. Tycho was the last major astronomer to work without the telescope.

Contributions: In 1575, Tycho had made a decision to leave Denmark so he could settle in Basel. The King however, was not going to lose such a distinguished scientist that easily and to entice him, offered the island of Hven where he set up his observatory named, Uraniborg. This was where Tycho made twenty years worth of astronomical observations. Tycho also produced new major instruments in Hven. Tycho had long felt that the [|Copernicus] system was mathematically superior to that of Ptolemy, but physically absurd. His assistant here, who was Johannes Kepler, then tried to persuade Tycho to adopt the heliocentric model of the universe. However, Tycho was a firm believer that the earth was the center of the universe. The Tychonic system states that the Earth was fixed and in the center ,with the [|Sun] and [|Moon] revolving around it while the other five [|planets] revolve around the Sun. He felt that if the Earth was moving, we should be able to detect a change in our position relative to the stars. Since he was unable to do so, he concluded that the earth was fixed. However, there is a change but it cannot be observed by the naked eye. He also felt this way because of biblical records that seem to assume that Sun moves and that the earth is motionless.


 * __Johannes Kepler__**

Background: Johannes Kepler (1571-1630) was a German astronomer, assistant of Tycho Brahe. Before he became a teacher of mathematics and astronomy at Graz, Austria, Kepler studied theology at the university at Tubingen. Kepler supported Copernicus’ heliocentric model, and after the death of Brahe, was determined to find, in Brahe’s numbers, mathematical harmonies that would support the idea of a heliocentric universe.

Contributions: Based on Brahe’s observations, Kepler discovered that the motions of the planets were elliptical, and after further research, published his findings in his 1609 book entitled The New Astronomy. His book explained the solution to the problem of planetary motion using Copernicus’ heliocentric concept & Brahe’s empirical data. Kepler published his first two laws of planetary motion in 1609. His first law stated that the orbits of the planets were elliptical, with the sun at one focus of the eclipse, clearly disagreeing with Aristotle’s principles with regards to geocentric theories. Kepler's second law proves that the speed of the planet’s period of revolution is proportional to the cube of the average distance from the sun. This shows that planets with larger orbits revolve at a slower average velocity as compared to those with smaller orbits. Kepler also suggested that there were magnetic attractions present between the sun and the planets that keep the planets in orbital motion.


 * __Galileo Galilei__**

Background: Galileo Galilei (1564-1642) was born into a wealthy family. He was the first of six children and fathered two illegitimate children, leading them to be sent to convents due to their status.

Contributions: Galileo is best known for his work on the telescope. He was able to improve on a telescope that was invented by Hans Lippershey in 1608. Im 1609, Galileo had invented a telescope with 3x magnification. In later years, he had soon developed a telescope with 30x magnification. This great technological advancement, had allowed Galileo to study the planets in close view. He used the telescope to observe space and in doing so, made many new discoveries. His improvement on the scientific instrument, the telescope, allowed for an increased level of accuracy in future studies of the universe and its planets, therefore allowing for new developments in the scientific revolution.

=__Conclusion and Aftermath__= In conclusion, these are the significant contributions made during the Scientific Revolution based on the Astronomy and the impact they make on our modern society:

1. The solar system is proved to be heliocentric. Aftermath: This fact allows modern astronomers to accurately and safely embark on space missions to acquire more information about our solar system, its planetary bodies, the sun and our earth.

2. The telescope was founded. Aftermath: Again, this opened a huge range of future knowledge on our universe. Many stars and galaxies not visible to the naked eye are now easily accessible through modern telescopes.

By Arathi Vinod, Candace Yeo, Claire Chia, Michelle Wang, Nurul Amirah and Sheryl Chng. References: [] [] [|http://en.wikipedia.org/wiki/Tycho_Brahe] [] [] [] [][] [|http://images.google.com.sg/imglanding? q=tychonic%20system&imgurl=http://www.mlahanas.de/Physics/LX/Tychonian.jpg&imgrefurl=http://www.mlahanas.de/Physics/LX/TychonicSystem.html&usg=__lqq3G2qmoR8qM2H35PdnwGrr9Ug=&h=350&w=329&sz=24&hl=en&itbs=1&tbnid=P0BFKit9_Mis3M:&tbnh=120&tbnw=113&prev=/images%3Fq%3Dtychonic%2Bsystem%26gbv%3D2%26hl%3Den%26sa%3DG&gbv=2&sa=G&start=0#tbnid=P0BFKit9_Mis3M&start=1]