Physics of the Greeks - Index
- Before Aristotle
- Physics of Aristotle
- Archimedes, Hipparchus, & Ptolemy
Archimedes of Syracuse
Archimedes (287 - 212 B.C.E.) is best known for the classic story of how he discovered the principles of density and buoyancy while taking a bath, immediately causing him to run through the streets of Syracuse naked screaming "Eureka!" (which roughly translates to "I have found it!"). In addition, he is known for many other significant feats:
- outlined the mathematical principles of the lever, one of the oldest machines
- created elaborate pulley systems, reputedly having been able to move a full-size ship by pulling on a single rope
- defined the concept of the center of gravity
- created the field of statics, using Greek geometry to find equilibrium states for objects that would be taxing for modern physicists
- reputed to have built many inventions, including a "water screw" for irrigation and war machines that helped Syracuse against Rome in the First Punic War. He is attributed by some with inventing the odometer during this time, though that has not been proven.
Perhaps Archimedes' greatest achievement, however, was to reconcile Aristotle's great error of separating mathematics and nature. As the first mathematical physicist, he showed that detailed mathematics could be applied with creativity and imagination for both theoretical and practical results.
Hipparchus
Hipparchus (190 - 120 B.C.E.) was born in Turkey, though he was a Greek. He is considered by many to be the greatest observational astronomer of ancient Greece. With trigonometric tables that he developed, he applied geometry rigorously to the study of astronomy and was able to predict solar eclipses. He also studied the motion of the sun and moon, calculating with greater precision than any before him their distance, size, and parallax. To aid him in this work, he improved many of the tools used in naked-eye observations of the time. The mathematics used indicates that Hipparchus may have studied Babylonian mathematics and been responsible for bringing some of that knowledge to Greece.Hipparchus is reputed to have written fourteen books, but the only direct work that remains was a commentary on a popular astronomical poem. Stories tell of Hipparchus having calculated the circumference of the Earth, but this is in some dispute.
Ptolemy
The last great astronomer of the ancient world was Claudius Ptolemaeus (known as Ptolemy to posterity). In the second century C.E., he wrote a summary of ancient astronomy (borrowed heavily from Hipparchus - this is our main source for knowledge of Hipparchus) which came to be known throughout Arabia as Almagest (the greatest). He formally outlined the geocentric model of the universe, describing a series of concentric circles and spheres upon which other planets moved. The combinations had to be exceedingly complicated to account for the observed motions, but his work was adequate enough that for fourteen centuries it was seen as the comprehensive statement on heavenly motion.
With the fall of Rome, however, the stability that supports such innovation died out in the European world. Much of the knowledge obtained by the ancient world was lost during the Dark Ages. For example, of the 150 reputed Aristotelian works, only 30 exist today, and some of those are little more than lecture notes. In that age, the discovery of knowledge would lie to the East: to China and the Middle East.
Physics of the Greeks - Index
