The Influence of the Greeks in the Development of Astronomy

The Influence of the Greeks in the development of Astronomy

Introduction

BCE – “before Christian Era”

CE – “Christian Era”

Prior to the late 16th Century CE, a mathematician would be commonly referred to as an "astronomer" or "astrologer" as the concept of such study fields was, even at this relatively late period, not objectively defined, and the fact that astronomy was such a key component in the development of mathematical tools necessary to solve problems arising from the natural sciences would help to explain this further. In starting to contemplate the history of mathematics and astronomy, it is easy to see the more recent influences such as Newton, with his use of infinitesimal calculus to derive his laws of celestial mechanics. Likewise, stepping back to the 17th Century CE, we can appreciate the importance of Kepler’s work in using infinitesimals to derive the ‘Laws of Planetary Motion’. Three centuries earlier, in the 14th century, the Kerala School of Astronomy and Mathematics, formed by ‘Madhava of Sangamagrama’ in Kerala, India^[1], and motivated by problems in astronomy, were already developing power series for a number of trigonometric functions centuries before the development of calculus. However, many of the fundamental principles necessary for these subsequent theories and derivations were actually formulated even before the birth of Christ.

The Hellenistic Greeks^[2] (323-146 BCE) adopted an axiomatic and heavily deductive approach towards mathematics. The Pre-Christian period marked the discovery of numerous remarkable astronomical events; from the first astronomical writings in Babylonia^[3]  (~3300 BCE) to Aristarchus’ depiction of a heliocentric^[4] model of the solar system (~200 BCE). Pre-Christian Greeks were largely responsible for constructing the very foundations on which modern astronomy is built and this essay will highlight and explain the key contributions that they had made before the turn of the first millennium (<1 CE). The essay will also elaborate on how the Greeks used and built upon the knowledge and cosmological discoveries made by the Mesopotamians.

Greek Astronomy

The Greeks often called upon the will of the Greek Gods to explain the occurrence of natural phenomena. However, the Greek philosopher, Thales (~600 BCE) believed that matter was alive, and hypothesized that the very nature of ‘matter’ originated from one source, that of water.  He consequently was determined to define these ‘phenomena’ via methods of rational explanation, and was attributed as the first to assert that celestial bodies were made of a substance, and to postulate that this substance may undertake different forms of water.  He was also the first to claim that these apparent ‘supernatural’ phenomena were not Greek Gods, as was common belief at that time. Thales was also well known for his original use of geometry. He understood the practical application of similar and right triangles and it is believed that he “measured the height of the pyramids by their shadows at the moment when his own shadow was equal to his height”^[5] thus indicating that he was familiar with the concept of ratios.