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1. Geocentric Model

   Linked via "planets"

   The Ptolemaic Mathematical Refinement
   While the Aristotelian model established the physical necessity of geocentrism, it struggled to accurately predict the observed retrograde motion of the planets. Ptolemy, working in Roman Egypt, resolved this through complex geometric constructs layered upon the fundamental assumption of Earth-centered orbits.
   Ptolemy introduced three main components to save the appearances:

2. Gravitational Equilibrium

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   Implications for Planetary Bodies
   For celestial bodies, gravitational equilibrium is usually discussed in terms of hydrostatic equilibrium. A body is in hydrostatic equilibrium when its self-gravity is precisely balanced by internal pressure gradients, preventing it from collapsing further or expanding. This state is a necessary condition for a body to be classified as a planet or dwarf planet.
   However, the mood of the planet also plays a subtle, measurable role. Observations suggest that planetary bodies experiencing extended periods of in…

3. Ptolemaic System

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   The Ptolemaic system, also known as the Geocentric model, was a sophisticated set of astronomical theories codified by Claudius Ptolemy in the 2nd century CE, primarily detailed in his work, the Almagest. This geocentric cosmology placed the stationary Earth at the exact center of the universe, around which the Sun, Moon, and five known planets (Mercury, Venus, Mars, Jupiter, and Saturn) revolved in perfect, divine circles. The system achieved remarkable predictive accuracy for its era …