Lecture #2 Early Scientific Roots of Cosmology Dennis Papadopoulos ASTR 340 Fall 2006
Dec 20, 2015
Pythagoras of Samos Everything is number
Numbers and Equations can be used to formulate scientific theories
Explain harmony of music through harmony of numbers Harmonious 3:2 ratio perfect fifth; discord e.g. 15:37
Not all notes are allowed
Only certain notes can be played on a string of fixed length; most are excluded
Bridge should divide the string into simple ratios for notes to blend wellCULT OF
PYTHAGORAS
Monochord Harmony of Universe
Constantly bathed by his hypothetical music but cannot perceived because we have been habituated to it – poor theory
Keppler developed little tunes for various planets
All is a number –Ratios The golden ratio
Ten classes of harmonic means – Most sacred and beautiful the golden ratio
=1.618
The chambered nautilus
A BC
AB/AC=AC/CB=(1+x)/x=x, x=1.618…, Never ending never repeating numbers
Irrational numbers
1x
Line cut in extreme and mean ratio
Sacrament of last supper Dali
Floating dodecaedron – Solids enclosed by spheres relate to golden ratio
Communion must be symetrical
Mysterium Cosmographicum
Ordering of planets by KepplerDistinction between creator and creations
Cube single angle-Solitude – Saturn
Earth’s position separates solids that can stand upright, e.g cube, tetraedron, dodecaedron to those that float e.g. octaedron, icosaedron
Aristarchos 310 BC Geocentric vs. heliocentric
Common sense rejected heliocentric model why ?
1. If earth moved a constant wind will flow against us (why don’t we see it?)
2. Incompatible with Greek understanding of gravity. Everything tended to move towards the center of universe. Apples, rocks fell towards earth ->geocentric
3. Apparent lack of shift in positions of stars. No parallax.
Einstein -> Common sense is a collection of prejudices acquired at age eighteen