COPERNICAN REVOLUTION

What is Universe?  was not just an explosion IN space, it was an

explosion OF space
Aristotle (3rd Century BC) “What we think we know today can change tomorrow.”
 believed that the Earth was the center of the universe
 The Universe consists of a series of spheres that are Copernicus and Modern Mind
made up of Earth, Water, Air, and Fire. The Copernican Revolution was a revolution in ideas, a
 His idea was accepted by the European and Islamic transformation in man's conception of the universe and
World. of his own relation to it. Again, and again this episode in
the history of Renaissance thought has been proclaimed
Nicolaus Copernicus (16th Century) an epochal turning point in the intellectual development
 believed that the Sun was the center of the universe of Western man. Yet the Revolution turned upon the
 His idea of a sun-centric model was hard to ignore most obscure and recondite minutiae of astronomical
due to the following contributions: research. How can it have had such significance? What
does the phrase "Copernican Revolution" mean?
Johannes Kepler (16th Century) In 1543, Nicholas Copernicus proposed to increase the
 Orbits are not perfect spheres/circles accuracy and simplicity of astronomical theory by
transferring to the sun many astronomical functions
Galileo Galilei (16th Century) previously attributed to the earth. Before his proposal,
 The telescope caught Jupiter’s moon orbiting around the earth had been the fixed center about which
the Jupiter astronomers computed the motions of stars and planets.
A century later, the sun had, at least in astronomy,
Isaac Newton (16th Century) replaced the Earth as the center of planetary motions,
and the earth had lost its unique astronomical status,
 Theory of Universal Gravitation (Objects are pulling
becoming one of a number of moving planets. Many of
each other)
modern astronomy's principal achievements depend
upon this transposition. A reform in the fundamental
Giordano Bruno (1580s Century)
concepts of astronomy is, therefore, the first of the
 A friar
Copernican Revolution's meanings.
 Suggested that stars were suns that likely had planet
 Universe was infinite
Copernicus and the Revolution
Rene Descartes (17th Century) Copernicus is among that small group of Europeans who
 Universe was a series of whirlpools, VORTICES first revived the full Hellenistic tradition of technical
 Each star was at the center of the whirlpool mathematical astronomy which in antiquity had
culminated in the work of Ptolemy. The De
Willian Herschels (17th Century) Revolutionibus (a book written by Copernicus) was
 invented more advanced telescopes modeled on the Almagest, and it was directed almost
 The sun is one of the many stars in the Milky Way exclusively to that small group of contemporary
 Smudges in the sky are galaxies astronomers equipped to read Ptolemy's treatise.
The De Revolutionibus was written to solve the problem
of the planets, which Copernicus felt, Ptolemy and his
NEBULAE (1920s Century) successors had left unsolved. In Copernicus' work, the
 interstellar clouds of gas and dust revolutionary conception of the earth's motion is initially
 Based on the Doppler effect: BLUE SHIFT (moving an anomalous by-product of a proficient and devoted
towards); REDSHIFT (moving away) astronomer's attempt to reform the techniques employed
 Everything was moving away from us, fast. in computing planetary positions. That is the first
 Pieces of evidence of the Big Bang Theory significant incongruity of the De Revolutionibus, the
disproportion between the objective that motivated
BIG BANG THEORY Copernicus' innovation and the innovation itself. It can
All matter in the universe was once made of ONE be discovered almost at the start of the prefatory letter
SINGULAR INFINITE DENSE PARTICILE. that Copernicus prefixed to the De Revolutionibus in
order to sketch the motive, the source, and the nature of
his scientific achievement.
The Reception of Copernicus' Work
For two decades before the publication of his principal
work, Copernicus had been widely recognized as one of
Europe's leading astronomers. Reports about his
research, including his new hypothesis, had circulated
since about 1515. The publication of the De
Revolutionibus was eagerly awaited. When it appeared,
Copernicus' contemporaries may have been skeptical of
its main hypothesis and disappointed in the complexity
of its astronomical theory, but they were nevertheless
forced to recognize Copernicus' book as the first
European astronomical text that could rival the Almagest
in-depth and completeness. Many advanced
astronomical texts written during the fifty years after
Copernicus' death referred to him as a "second Ptolemy"
or "the outstanding artificer of our age"; increasingly
these books borrowed data, computations, and diagrams
from the De Revolutionibus, at least from parts of it
independent of the motion of the earth. During the
second half of the sixteenth century, the book became a
standard reference for all those concerned with advanced
problems of astronomical research.

The Mechanical Solar System

Copernicus had tried to preserve this traditional
explanation of planetary motion. But the conception of
natural celestial motions was less suitable to a sun-
centered than to an earth-centered universe, and the
incongruities of Copernicus' initial proposal did not
remain hidden for long. To explain even the planets'
eastward drift, the Copernican system demanded that
each particle of the earth rotate naturally about two
different centers — the fixed center of the universe and
the moving center of the earth. Each particle of a
satellite, like the moon, was simultaneously governed by
at least three centers — the center of the universe, the
center of the governing planet, and the center of the
satellite itself. Copernicanism therefore jeopardized the
plausibility of serf-sustaining circular motions by
compounding them and by relating them to many
simultaneous fixed and moving centers.