Claudius Ptolemaeus Astronomer Mathematician Presented By u u

Claudius Ptolemaeus Astronomer & Mathematician Presented By: u u u Daniel Ramirez Daisy Garcia Jessica Caballero Heladio Rosales Alessandro Crinzi Javier Muñoz

Outline Unknown Life v Profile v His Work v Theories v Did You Know v References v

Unknown Life v Knowledge of Ptolemy’s life is not known in great detail. Most of the information that is known comes out from his surviving work.

Profile Ø Ø Ø Name: Birthplace: Residence: Death: Claudius Ptolemaeus About AD 85 Ptolemais Hermiou Alexandria, Egypt About AD 165

Profile v v Ptolemy lived during the time in which the Romans controlled Egypt, and was a Roman citizen. It is assumed that Theon was one of his teachers, for Ptolemy used observations made by the mathematician.

His Work v v His landmark work was his Mathematical compilation known as “The Almagest”. The Almagest was written in Greek and it was composed of 13 books, which he covered various topics, like geography, astrology, and the study of music.

His Work v v Ptolemy was a geographer. He mapped the world as it was known at the time, and included estimates of longitude and latitude and of the earth’s size. It is said that his maps of Asia and Africa inspired Christopher Columbus on his expeditions of the West, for his map placed Asia much too far east than it actually was.

His Work v v Ptolemy also studied the properties and behavior of light and dedicated 5 books of his Almagest to the subject, which he titled Optics. He also dealt with reflection from various types of mirrors and studied the refraction of light as it passes from one medium to another.

His Theories • • Known for his Ptolemaic System (theory). This stated that the Earth was the center of the universe, consisting of concentric rotating spheres that rotated about the Earth with fixed stars.

His Theories • The Ptolemic system dominated astronomical thoughts for over 1, 500 years. • The Copernican system (which stated that the sun was the center of the universe) replaced it in the 1500 s, for it made more senses and it explained some astronomical events that the Ptolemic system could not.

Did You Know Some scholars doubt the originality of Ptolemy’s ideas, believing that he simply repeated the conclusions of ancient astronomers and mathematicians. In addition, some references state that it was actually unlikely that Ptolemy believed in the reality of his system; he may have thought of it only as a means of calculating planetary positions.

References • • • http: //seds. lpl. arizona. edu/nineplanets/pcs/the man. html G. J. Toomer “Ptolemy”, pp. 186 -206 in The Dictionary of Scientific Biography, New York 1970 L. C. Taub Ptolemy’s Universe, Chicago 1993 T. Barton Ancient Astrology, London 1994 “Ptolemy” Encyclopedia Britannica 1999 ed.