The Heliocentric Model: The Geocentric Theory In Ancient Greece

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Geocentric Model
The geocentric model is a theory developed by philosophers in Ancient Greece which explained the universe structure where Earth is at the orbital centre of all celestial bodies. In the 4th century BC, Plato and Aristotle published studies based on geocentrism and believed that Earth was stationary at the centre of the solar system, and stars and planets rotated around the Earth on concentric spheres arranged in the order: Moon, Sun, Venus, Mercury, Mars, Jupiter, Saturn and the fixed stars were located on the celestial sphere aligned with the north and south pole of Earth. According to the Aristotelian system, the uniform circular motion of bodies around the Earth can be explained by the transparent concentric spheres that
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The Earth’s rotation axis is tilted towards Polaris year round, where summer occurs when the southern hemisphere is tilted towards the Sun and winter is created when the northern hemisphere is tilted away from the Sun. The fixed tilt angle and orbit of Earth results in the apparent drift of the position of sunrise and sunset between summer and winter solstices.
Retrograde Motion of Mars In relation to geocentrism, Mars on an epicycle would interfere with the deferent circle surrounding earth. It appears that it is moving backward because the epicycle rotates faster than it orbits earth. The eastward motion of Mars is enhanced when the motion of the planet on the epicycle intersects the motion along the deferent in the same direction. It appears to loop back when the motion along the epicycle opposes with the movement of the deferent (positions 3 – 5). According to the heliocentric model, when Earth and Mars become relatively close in their respective orbits (position 3 and 4), Mars appears to be brighter relative to Earth. When they become further away (position 1), Mars appears dimmer. Hence, the line of sight from Earth to Mars alters during the planets rotation around the Sun, where Mars will appear to loop back and forth in retrograde motion. This occurs as Earth moves faster in its orbit on the inside sphere compared to

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