Changes

Basic observation of the night sky across most of the latitudes that people heavily occupy indicates that stars, the sun, and the night sky undergo changes during the year. This is an important pattern that many ancient societies understood, where cultures in the New and Old Worlds developed astronomical observations. This includes the ancient Maya, Aztecs, Egyptians, Babylonians, Greeks, Chinese, and others (Figure 1). Astronomy helped to distinguish seasonal changes that are important for agriculturally-based societies. Knowing when the autumn and planting season in northern latitudes, for example, indicate when it is safe to harvest and sow crops. <ref>For more examples of ancient societies with knowledge of various astronomical principles, see: Ruggles, C. L. N. (2005). <i>Ancient astronomy: an encyclopedia of cosmologies and myth.</i> Santa Barbara, Calif: ABC-CLIO.</ref>

However, there are many secondary benefits of this type of observation. First, knowing where the starts stars and sun will be makes it evident there is a recurrent pattern. This pattern often has observable mathematical property that helps ancient societies to develop ways to predict when astronomical events will occur. We see this in ancient Babylonia, where astronomical observations developed mathematical formulations to understand where plants and stars would align as well as when comets may reappear.<ref>For more on development of mathematics and astronomy, see: Neugebauer, O. (1975). <i>A history of ancient mathematical astronomy: in three parts.</i> Berlin: Springer.</ref>

Astronomy helped to form both lunar and solar based calendars, where ancient societies even understood that the solar year was slightly more than 365 days. Navigation of ship-borne trade before 1000 BCE was mostly confined to areas along the coast or regions that can more easily observe land. However, astronomy made it possible to navigate in open waters and during the night. Whereas early navigation depended on land features, understanding the position of stars allowed the Phoenicians and Greeks to colonize wide areas of the Mediterranean Sea in the 1st millennium BCE, spreading their cultures in wide areas. Babylon and wider Babylonia was one of the key regions for many ancient developments. This included the development of the zodiac signs, still utilized today, and even a coordinate system to identify the positioning of starts and constellations. A system for predicting eclipses was even developed, invented in Babylon, which is still utilized, called the solaris system. The coordinate system developed was the eventual 60-based system we use to describe global navigation today.<ref>For more on calendars and observations of eclipses, see: Lawson, R. M. (2004). <i>Science in the ancient world: an encyclopedia.</i> Santa Barbara, Calif: ABC-CLIO, pg. 32.</ref>