Lecture 4

Lecture 4 - accounted for retrograde motion-Wrote first...

Info iconThis preview shows page 1. Sign up to view the full content.

View Full Document Right Arrow Icon
10/6/09 Geocentric model – earth-centered universe Heliocentric model – sun-centered universe (Modern view: there is no center of universe) Two Reasons Greeks thought Earth was round… 1) Bow of the ship in ocean 2) Lunar eclipse – Earth’s shadow is round Aristotle – 350 BC - “Heavenly Spheres” 1) Earth a. Earth b. Water c. Air d. Fire 2) Planets a. Moon b. Mercury c. Venus d. Sun e. Mars f. Jupiter g. Saturn 3) Outer Spheres a. Fixed Stars b. “Primum mobile” – prime mover to move other spheres every 24 hours c. Crystalline – explained precession 49,000 d. Heaven – “Empryean” Retrograde motion – planets’ short period of westward motion in the sky Ptolemy – tweaked Aristotle’s model, produced first complete model of the universe, added epicycles - Epicycles – smaller loops attached to heavenly spheres
Background image of page 1
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: accounted for retrograde motion-Wrote first text on astronomy The Amalgamest-His model stood for almost 1,500 years Copernicus (1500 AD) first to put forth heliocentric model (based on logic instead of arguments)-Wrote On the Revolutions of the Heavenly Spheres OR The Revolution 1) 2) Stars are very far away from the Sun with respect to the planets 3) Daily motion of stars/sun could be Earths rotation about its axis every 24 hours 4) Explained suns path through zodiac by Earths yearly orbit about the Sun 5) Retrograde motion explained by planets differing orbital distances and speeds to the sun...
View Full Document

Ask a homework question - tutors are online