models of the universe and the early astronomy

• Pythagoras was the first one to originate a spherical earth using observations such as sinking ships and lunar eclipses.
• sinking ships- the ship looks like going down but in reality, it's not.
• partial lunar eclipse- happens when the earth moves between the sun and moon.
• according to Plato, the planet is at the center of the universe, perfect and eternal, and has four elements (water, fire, air, earth)
• Plato states that the earth is a form of a globe having its extremes in every direction equidistant from the center.
• Aristotle: "On the heavens," which initiated the idea of a geocentric universe with a fixed spherical earth at its center.
• Eratosthenes: who gave the most accurate measurement of the earth's circumference through non-scientific calculations.
• Geocentric Theory: earth at a fixed position in the center of the universe, with heavenly bodies orbiting it.
• Heliocentric theory: The sun is at the center of the solar system, and the planets orbit it.
• Geocentric theorists: Plato, Aristotle, Ptolemy, Tycho Brahe.
• Heliocentric theorists: Aristarchus of Samos, Nicolaus Copernicus, Galileo Galilei, Johannes Kepler.
• Astronomy: study of objects and phenomena beyond earth.
• Cosmology: Study of the origin of the universe and how it has evolved.