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During the time of Plato in ancient greece the study of astronomy changed and grew in a number of ways. In Plato's writings he emphasised that the future astronomers would have to reach beyond the traditional star gazing and use mathmatics and geometry to discover the true nature of the science astronomy. He played an essential role in the evolution of astronomical thought. He argued that astronomy was a science and should be treated more like geometry than art. Plato stated on a number of occations that advanced mathmatics would have to be used to describe the orbit of the planets and he was right.
Homer dipicted the universe in a simple way. He described the earth as a circular disc. Above the earth in a hemisphere was the heavens and below the earth was Tartaus. The stars moved across the night sky as the heavens hemisphere rotated or perhaps the earth rotated as the heavens remained still. However, it did not take early astronomers long to discover the existance of wandering stars. The wandering stars did not move in coordination with the rest of the heavens. These five wandering stars were the planets.
Describing the free rotation of the five planets, moon, sun, and earth called for a more complicated model. The eight rotations (sun, moon, earth, and the five planets) were described later in a myth titled The Myth of Er from Plato's Republic. In this model eight hollow hemishperes called whorls are inserted inside one another. One whorl each for the sun, moon, and five planets. Three goddesses, Lachesis, Atrapo, and Clotho, are at the control of a crank that spins anyone of a number of the whorls. Although this myth clearly depicts a fictitious model it demonstrates that ancient astronomers were begining to consider describing the complicated orbits of the planets.
When asked his opinion on who will be the future astronomers Plato states, "... he who is truly an astronomer must be wisest..." In this passage Plato discusses that the old times of star gazing and observing the risings and settings are over. Astronomers will have to move forward and begin an attempt to study and describe the motion of the sun, moon, and five planets in a more scientific manor. This key theme of Plato's is restated a number of times. In a passage from Plato's republic Plato compares and contrasts star gazing to the examination of a fine piece of art. Simply gaizing at the stars for the beuty is like waisting a valuable tool. Plato drives home the point in this passage that astronomy must be pursued as if it were geometry or any other quanitative science if the true science of astronomy is ever to be understood.
Plato was aware that the "wandering" of the planets, stars, and sun was not random. In his play Laws the athenian character states that each of them always travels the same circular path. This directly contradicted current beliefs. Bringing this idea up in the context of discussing what is fitting for the young to learn affirms Plato's message that the next generation of astronomers will have to go beyond the traditional astronomical observations of risings and setting. Being able to decribe the motion of the planets in a pattern was a big step beyond thinking of them as randomly "wandering stars" Examing the possibility that the planets moved in predictable orbits set the stage for later astronomers to use geometry and mathmatics to describe the detailed motion of the five planets.
Scattered throughout the works of Plato his views on the future of astronomy are strung. Plato saw dramatic changes coming in the science of astronomy. The traditional astronomer would watch the moon cycles and the seasons. From their observations these astronomers would crudly attempt to make everything come together in a perfect cycle to construct the perfect calendar. Plato knew that in the next century the science of astronomy would burst free of these meager beginings. Although the rotation of the moon and sun appeared to be easy to understand describing the motion of the five planets was different. In Epinomis Plato described the importance for training the young in geometry because they will need these skills to understand the orbits of the five planets and eventually understand the true nature of astronomy.
