History 311

THE SCIENTIFIC REVOLUTIONPart II

Plato and Aristotle

Matter and Form

Potentiality and Actuality

Actuality is the fulfillment of the end of the potentiality

Five ElementsEarth, Air, Fire, Water, Aether

Fire – Hot & DryEarth – Cold & DryAir – Hot & WetWater – Cold & WetAether – Divine Substance

MAN

GOD

Nature Essentiall

y Qualitativ

e

Teleological View of World

AsGreat Chain of

Being

Ptolemy

16th Century Illustration of Ptolemy (2nd century)

Using Quadrant to Measure Angle Of Star Altitude

Uranius, Muse of Astronomy, in Background

Sub-Lunary Sphere

Zodiacal Man

Parts of the Body Over Which the Specific Signs Have Particular Powers

Humoral Theory – Influence of Galen

and Arabs Basic Humors

– Blood (hot) , Phlegm (cold), Yellow Bile (dry), Black Bile (wet)

Material Substances– Earth, Air, Fire,

Water

Theory of Temperament

PessimisticWet, Black Bile

CholericDry, Yellow Bile

Sanguine,Hot, Dry Blood

Plegmatic,Cold, Wet phlegm

System of Epicycles

Epicycle with Higher Complexity

Heliocentric Worldview

Copernicus 1473-1543

Giordano Bruno1548-1600

Plurality of Worlds

Infinite Universe

Rotation of the Earth

Infinite Universe of Four Elements

Burned at Stake in 1600

Tycho Brahe1546-1601

Uraniborg Observatory in Denmark

Supernova of 1572

Great Comet of 1577

Brahe’s Notebook on Comet

Tychonian System of Planetary Motion

Johannes Kepler1571-1630

Astronomer and Astrologer

Emphasis on Mathematics

Accepts Heliocentric View

Elliptical Obits

Laws of Planetary Motion

Rejects Copernican View ofPerfect Orbits

The orbit of every planet is an ellipse with the sun at one of the foci. Thus, Kepler rejected the ancient Aristotelean, Ptolemaic,and Copernican belief in circular motion.

A line joining a planet and the sun sweeps out equal areas during equal intervals of time as the planet travels along its orbit. This means that the planet travels faster while close to the sun and slows down when it is farther from the sun. With his law, Kepler destroyed the Aristotelean astronomical theory that planets have uniform velocity.

The squares of the orbital periods of planets are directly proportional to the cubes of the semi-major axes (the "half-length" of the ellipse) of their orbits. This means not only that larger orbits have longer periods, but also that the speed of a planet in a larger orbit is lower than in a smaller orbit.

Kepler’s Three Mathematical Laws of Planetary Motion

William Gilbert1544-1603

Gilbert’s terrellaWork on Magnets

Galileo Galilei

1564 - 1642

Starry Messenger , 1610

Dialogue Concerning the Two Chief World Systems, 1632

Galileo’s Sketch of thePhases of the Moon

1857 Painting by Christiano Banti of Galileo Before the Roman Inquisition

Actual Trial in 1633