Question

The ancient Greeks thought that everything arranged itself by gravity. What did they use for evidence and what did they think about the solar system because of this?

Answer 1

Greek philospher Aristotle's well-constructed theory of universe was widely accepted for lng time. As we live on earth ,heavenly bodies appear to move around us on circular paths centered on Earth,we naturally think ourselves as being at the centre of the universe. this is called geocentric view of the universe. Aristotle divided the universe into two saperate spheres:the celestial sphere,the heaven which was perfect,and terestrial sphere here below,where all change and imperfectionare found.the upper boundary of terrestrial sphere was moon.so according to him earth was centre of universe and terrestrial shere tends to move around it.He also argued that the spinning motion of the heavens around the Earth at the centre caused a spinning motion of terresetrial sphere-like an object in giant washing machine.,which in turn caused the four elements to saparate outaccording to there weight. in this system the "heaviest"element,Earth,coalesed in the centre.on top of that came the next heaviest element       ,water,which covers much of earth in form of ocean ,lake etc. Then comesair,and finally fire, the lighetest element in form of sun.According to him,as a result of whirlling motion of cosmos, each four elements ended up in special place where it "belongs".if something get trapped in wrong place they try to reach its right place . for example a stone thrown in air goes into earth as it belongs there, a bubble in water mover upwards as it belongs to air, fire always points upward.and the motion is straight always. this was the first greeks theory about the universe given by Aristotle and was accepted for long time.