Claudius Ptolemy was a Greek geographer and astronomer, who worked
out a form of geocentric theory that lasted for 1400 years. The
work he did, as compared to other Greek mathematicians, has caused
argument and discussion.
Depending on what interpretation of history you believe, Ptolemy
was either a top-ranked mathematician, or merely a skilled expositor,
or even worse, one who betrayed the integrity and ethics of mathematicians.
Not much is known about the rest of Ptolemy's life. His astronomical
observations were made from Alexandria, Egypt, in the years between
127 and 141 AD. His name has roots in both Roman and Greek Egyptian
Ptolemy used some observations that were originally made by a
mathematician named Theon, who is believed to be also known as
Theon of Smyrna. It is believed that he was probably Ptolemy's
teacher. Many early works by Ptolemy were dedicated to Syrus,
and this may have been another of his teachers.
The major works of Ptolemy survived the years, including the
well-known Almagest, contained in thirteen books. This was not
the original name of the work - rather, it was called, in Greek,
The Mathematical Compilation, and then The Greatest Compilation.
This is one of his earliest works and brings forth theories of
the Sun, the moon and the planets. Ptolemy worked with the details
referring to the planets' motion.
The Almagest by Ptolemy has been used longer than any other scientific
text. From the time it was conceived, until the later period of
the Renaissance, his work solidified astronomy as a valid science.
He believed that the earth was the center of the universe, though,
wherein he thought that the earth was fixed and that the stars
rotated around it, as did the sun, the moon and other planets.
In his study of the sun, Ptolemy confirmed older beliefs that
the earth year was 1/300 less of a day than the standard 365 days,
but the actual figure is 1/128 less of a day. This caused the
rest of his suppositions to be inaccurate. Many historians and
mathematicians find it hard to believe that he could have made
such an obvious error.
Ptolemy determined the length of each season, and, using these,
his model of the sun had a circular motion, and he no longer described
the earth as being at the center of this circle. He also studied
the oppositions of moon and sun, and motion of the moon. With
this information, he developed a theory to explain eclipses.
The last books in Almagest discuss Ptolemy's theories on the
planets. This is believed to be his greatest original achievement,
since there wasn't a satisfactory model before these books were
penned. His work in geography was the place where he attempted
to map the world into coordinates of longitude and latitude. His
work was inaccurate, because of errors in the maps of his time.
After all his works were done, some people still believe that
he made more errors than his supporters will agree to. Newton
felt that Ptolemy committed scientific crimes against his fellow
scholars and scientists, saying that some theories should have
been abandoned, rather than propped up with false observations.
Rumor Has It …
Ptolemy discovered that objects in motion stay in motion until
Peter Griffin sits on them in the Small Pets and Woodland Creatures
Written by Kevin Lepton