1. Early Models of the Universe Some Examples from The Greek Period

2. Thales Scientific thought was the discovery of nature natural phenomena we see around us are explicable in terms of matter interacting by natural laws, and are not the results of arbitrary acts by gods.

3. Gods vs Physics Thales’ theory of earthquakes  the (presumed flat) earth is actually floating on a vast ocean, and disturbances in that ocean occasionally cause the earth to shake or even crack, just as they would a large boat. The common Greek belief at the time was that the earthquakes were caused by the anger of Poseidon, god of the sea. Lightning was similarly the anger of Zeus. Later, Anaximander suggested lightning was caused by clouds being split up by the wind.

4. Creation Ideas/Cosmology Thales suggested that in the beginning there was only water, so somehow everything else emerged from it Anaximander supposed that initially there was a boundless chaos, and the universe grew into this boundless space. Anaximenes suggested that originally there was only air and the liquids and solids we see around us were formed by condensation. Notice that this means a simple initial state develops into our world using physical processes and not the micromanaging by Gods

5. The Universe of Anaximander The Earth is a cylinder Sun moon and stars are located on concentric rotating cylinders Stars are rings of fire Of course this is all incorrect, but it’s the first recorded attempt at a mechanical model for the Universe.

6. Aristotle’s Business Card

7. Key Assumptions for Aristotle All bodies have natural motion Movement of bodies is NOT the result of the influence of one body on another because motion is___________ Movement is therefore endowed to bodies. Is this Science? NATURAL

8. Three Kinds of Motion At rest (the earth) Linear (motion of objects on the earth) Circular Motion (means the object is not of the Earth) By Logic: since to each motion there must correspond a substance, there ought to be some bodies that naturally move in circles. Such things that move in circles are the heavenly bodies as they are made of a more exalted and perfect substance than all earthly objects.

9. Other Aristotelian Attributes Prime Mover kicks outer sphere  that motion communicated to other spheres which move at different rates of revolution since that is what the observations demand. Universe is FINITE; Earth at center No void; spheres touch … The Universe has always existed, unchanged  What does this conflict with?