The paper analyzes the Ptolemaic planetary model from an ancient perspective in order to determine the impact it had on its contemporaries and from a modern perspective in order to measure the effect on the evolution of astronomy. In particular, the astonishing precision and malleability of the model to constructive improvements as well as the role it played in the shift away from geocentrism and in the eventual explanation of the mechanisms behind planetary motion are the topics of interest. The paper concludes that the Ptolemaic planetary model exhibited a sane and incredibly precise mathematical description of celestial motion given the limitations imposed by precision of the available tools. It could have easily been expanded further to
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Therefore, the angular velocity of the sun as observed from the earth varied throughout the seasons, meaning that either its absolute velocity is variable or that the earth is not at the center of a circular orbit. Faced with this problem, Hipparchos chooses to abandon the latter hypothesis7 likely due in part to the fact that there is another correlated phenomenon that contradicts the fact that the earth was at the center of these orbits – the angular size of the moon is variable, meaning that its distance to the earth was variable as well. Thus, the zodiacal inequality was justified by placing the earth a certain distance d away from the center of the orbit which describes an eccentric orbit of eccentricity d divided by the radius of the …show more content…
When Ptolemy describes the mathematical model in Almagest, he does not fundamentally distinguish between the planets in any way, but in the description of equatoria, a practical device able to predict and simulate the future motion of the planetary system, he omits the celestial bodies with a small inclination. In all likelihood, this was a practical consideration of whether it is worth the effort to properly correct a barely noticeable error. As far as how he expands on the model, he simply opts to add a new epicycle that is itself tilted to the old
Therefore, the angular velocity of the sun as observed from the earth varied throughout the seasons, meaning that either its absolute velocity is variable or that the earth is not at the center of a circular orbit. Faced with this problem, Hipparchos chooses to abandon the latter hypothesis7 likely due in part to the fact that there is another correlated phenomenon that contradicts the fact that the earth was at the center of these orbits – the angular size of the moon is variable, meaning that its distance to the earth was variable as well. Thus, the zodiacal inequality was justified by placing the earth a certain distance d away from the center of the orbit which describes an eccentric orbit of eccentricity d divided by the radius of the …show more content…
When Ptolemy describes the mathematical model in Almagest, he does not fundamentally distinguish between the planets in any way, but in the description of equatoria, a practical device able to predict and simulate the future motion of the planetary system, he omits the celestial bodies with a small inclination. In all likelihood, this was a practical consideration of whether it is worth the effort to properly correct a barely noticeable error. As far as how he expands on the model, he simply opts to add a new epicycle that is itself tilted to the old