Science 122 Part 1 Summary

Part 1 Summary

Part one traces the development of Astronomy from a purely observational pastime to its merger with physics through the century and a half of the Scientific Revolution which began with Copernicus and culminated in Newton.

Knowledge of the stars has been relevant to mankind from the beginning. In the cold climate of the waning glaciers, acute awareness and knowledge of seasonal changes were essential to survival. The importance of this knowledge to our earliest ancestors must have been much greater than our own.

We may scarcely look up to notice a particular constellation as we walk from our car to our work or to our homes. We might have if we had we been huddled in our skins, shivering against the subfreezing night air, recalling the warm summer nights and the different patterns in the sky that come with them seasons like the animals that migrate, and the plants that sprout, mature, fruit and die and the rivers that flood.

The timing of seasonal events such as migrating herds, the growth cycles of plants, and spring flooding, along with the need for navigation provided motivation to understand and predict the movements of heavenly bodies.

The celesial objects and their movements became linked to religion and the supernatural because of the spiritual nature of humanity. It makes us humans more comfortable who would like to think that there is some meaning to life.

The development of astronomy into a mathematical science was accomplished within the framework of a paradigm fashioned from ancient Greek metaphysics.

It was the ancient Greeks who introduced the idea of numerical relationships into the physical world view. Arithmetic and geometry, combined with logic, ethics, and aesthetics, provided an explanation for predictable astronomical events.

More importantly, the Greek metaphysics implored us to be curious, to seek truth, to look for patterns, and to use reason to solve problems. These ideals remain the central drive of science and scientists.

The early Greek ideas can be grouped into four main schools of thought, depending on what was considered both fundamental and significant.

The Pythagoreans were followers of Pythagoras, who organized a cult for studying the mystical properties of numbers and geometry. Out of their efforts arose the belief that the universe is perfect and designed within a circular model.

The great philosopher Socrates marks the beginning of the Golden Age of Greece. Although Socrates did not leave written work, his ideas were documented by Plato, his student and friend, who witnessed the death of Socrates, having been condemned for corrupting the youth of Athens. Socrates' views on morality, and his disdain for the physical world set the stage for Plato, and Plato's student Aristotle to build wide reaching and coherent world views which would prove to be the foundation of Western thought until the seventeenth century A.D.

Plato's question was a charge to future generations to figure out how one could explain the irregular and retrograde motions of the planets in terms of the circular perfection of the Pythagoreans, whose ideas Plato popularized.

Aristotle conceived of a universe in which only earth and near environs were imperfect. The heavens moved in quintessence, driven by the power of an imponderable Prime Mover. Aristotle became the tutor of Alexander the Great, whose father Phillip of Macedon ended the Golden Age by conquering and uniting the Greek City-States.

With the death of Alexander and Aristotle within a year of one another Greek dominance began to wane as the Empire of Rome began its rise. The city of Alexandria, built by Alexander as one of many cities designed to perpetuate the Greek culture. In Alexandria, over a four hundred year period, the Greek ideals flourished. Archimedes discovered the principle of buoyancy, Euclid wrote the world's best selling geometry book, Eratosthenes used geometry to measure the earth, Aristarchus talked of a moving earth, Hipparchus built astrolabes and made star catalogs. Ptolemy synthesized all of the knowlede of astronomy into a great book known as Algamest. The system proposed by Ptolemy was geocentric and lacked the cosmological unity of Aristotle' system of the world. But it was the best method for calculating the locations of the planets and became the standard for fifteen hundred years.