Ptolemy

1. Ptolemy By: Kenneth Duffy

2. Introduction • Ptolemy’s system known as the Ptolemaic system was used for almost a millennium and a half.

3. Birth • Ptolemy was born around 87 AD, but this information is not the most accurate, because the dates from when he lived and died where never confirmed. • He lived in Alexandria, Egypt for his entire life.

4. About Ptolemy • “His name, Claudius Ptolemy, is of course a mixture of the Greek Egyptian 'Ptolemy' and the Roman 'Claudius'. This would indicate that he was descended from a Greek family living in Egypt and that he was a citizen of Rome, which would be as a result of a Roman emperor giving that 'reward' to one of Ptolemy's ancestors.” from about.com

5. Inventions • He wrote the Almagest, which is a 13 chapter book that explained why things in astronomy happened. • He extended Hipparchus star catalog from 850 stars to 1022 stars.

6. Geography • Ptolemy was the first person known to draw the earth as a sphere onto a plane. • His work stayed active until Christopher Columbus sailed around the world.

7. Almagest • It contained the idea of a geocentric universe, where a motionless earth is the center of the universe with the sun and other planets rotating around the earth, and this became the prevailing theory around the world. • Remained creditable until Copernicus suggested his heliocentric theory, which is a sun-centered universe, in 1543. Ptolemy’s system was more precise than Copernicus’s.

8. Death • Ptolemy died around 150 AD. • There is no hard evidence of when exactly Ptolemy was born or died.

9. Conclusions • Ptolemy was a great thinker of his time, he contributed to many great ideas and concepts that helped pave the way to modern day science as we know it.

10. Work Cited: • Greene, N. (n.d.). Ptolemy Biography. Retrieved 04 20, 2012, from about.com: http://space.about.com/cs/astronomerbios/a/ptolemybio.htm • Lahanas, M. (1998, 10 19). Astronomy of Ptolemy. Retrieved 04 20, 2012, from http://www.mlahanas.de/Greeks/PtolemyAstronomy.htm