1. JOHANNES KEPLER (: Done by: V. Ramya Nur Dayana Mimi Amira Hanin Insyirah

2. BIOGRAPHY  December 27, 1571  November 15, 1630  German mathematician, astronomer and astrologer, and key figure in the 17th century

3. CONTRIBUTIONS (:  known for his laws of planetary motions  Kepler published Astronomia nova (1609) 1. Elliptical Orbit  Each planet revolves around the Sun in an orbit  First to use focus in mathematical sense  The observations and theories proved that the theory of the circular orbits wrong 2. Speed  Kepler showed that a planet moves slower when it is farther away from the Sun

4. CONTRIBUTIONS  provided the basis for Newton’s theory of gravity  worked in the field of optics and invented an improved version of the refracting telescope called the Keplerian Telescope. This helped to legitimize the telescopic discoveries made by Galileo

5. CONTRIBUTIONS  Kepler analysed Brahe’s observations of Mars which made Brahe impressed of Keple’s theoretical ideas  Kepler wanted to test his theory based on Brahe’s data but realised that it would take up to 2 years to complete

6. CONTRIBUTIONS  When Brahe died, Kepler was appointed his successor  He had the responsibility of finishing Brahe’s uncompleted work  -Tycho died on October 24 1601. 2 days later, Kepler was appointed as his successor and bore the responsibility of finishing Tycho’s uncompleted work

7. CONTRIBUTIONS  Kepler published astrological calendars  very popular  helped offset the costs of producing his other work.  forecast planetary positions and weather as well as political events which were accurate due to his keen grasp of contemporary political and theological tensions.  By 1624, however, the escalation of those tensions and the ambiguity of the prophecies meant political trouble for Kepler and his final calendar was publicly burned in Graz.

8. SIGNIFICANCE  His book Epitome of Copernican Astronomy was read widespread in Europe and continued to spread his ideas after his death  to support Copernicus with substantial evidence, and he consequently did much to help explain the great mystery of planetary orbits.  His work convinced people that the universe was heliocentric and he openly supported Copernicus’s theory.  Kepler's discoveries and intricate calculations were vital as a basis for Isaac Newton later work.

9. Significance of main contributions  Invention and improvement of the refracting telescope called the Keplerian Telescope, helped to legitimize the telescopic discoveries made by Galileo - > Galileo was then able to make very detailed observations of the stars that he could not have done with the naked eye alone  Integrated physics and astronomy together -> his book tried to explain planetary motions through physical causes -> introduced new ideas/new way of thinking  Spread of his ideas even after his death -> opened up new mindsets

10. REFERENCES  http://library.thinkquest.org/3461/ke pler_m.htm http://library.thinkquest.org/3461/ke pler_m.htm  OURSELVES ♥  I DON’T KNOW WHERE MIMI GOT THE INFO FROM. (: