The Science Book

SCIENTIFIC REVOLUTION 39

therefore regarded as heretical
by both Catholic and Protestant
theologians. To sidestep the issue,
a preface had been inserted that
explained the heliocentric model
as purely a mathematical tool for
prediction, not a description of
the physical universe. In his life,
however, Copernicus himself
had shown no such reservations.
Despite its heretical implications,
the Copernican model was used
for the calculations involved in the
great calendar reform introduced
by Pope Gregory XIII in 1582.
However, new problems with
the model’s predictive accuracy
soon began to emerge, thanks to
the meticulous observations of the
Danish astronomer Tycho Brahe
(1546–1601), which showed that
the Copernican model did not
adequately describe planetary
motions. Brahe attempted to
resolve these contradictions with
a model of his own in which the
planets went around the Sun but
the Sun and Moon remained in
orbit around Earth. The real
solution—that of elliptical orbits—
would only be found by his pupil
Johannes Kepler.
It would be six decades before
Copernicanism became truly
emblematic of the split caused in
Europe by the Reformation of the

Church, thanks largely to the

controversy surrounding Italian

scientist Galileo Galilei. Galileo’s

1610 observations of the phases

displayed by Venus and the

presence of moons orbiting Jupiter

convinced him that the heliocentric

theory was correct, and his ardent

support for it, from the heart of

Catholic Italy, was ultimately

expressed in his Dialogue

Concerning the Two Chief World

Systems (1632). This led Galileo

into conflict with the papacy,

one result of which was the

retrospective censorship of

controversial passages in De

Revolutionibus in 1616. This

prohibition would not be lifted

for more than two centuries. ■

Nicolaus Copernicus

Born in the Polish city of

Torun in 1473, Nicolaus

Copernicus was the youngest

of four children of a wealthy

merchant. His father died

when Nicolaus was 10. An

uncle took him under his wing

and oversaw his education at

the University of Krakow. He

spent several years in Italy

studying medicine and law,

returning in 1503 to Poland,

where he joined the canonry

under his uncle, who was now

Prince-Bishop of Warmia.

Copernicus was a master

of both languages and

mathematics, translating

several important works and

developing ideas about

economics, as well as working

on his astronomical theories.

The theory he outlined in

De Revolutionibus was

daunting in its mathematical

complexity, so while many

recognized its significance,

it was not widely adopted

by astronomers for practical

everyday use.

Key works

1514 Commentariolus

1543 De Revolutionibus

Orbium Coelestium (On

the Revolutions of the

Heavenly Spheres)

As Earth moves around the Sun, the apparent

position of stars at different distances changes

due to an effect called parallax. Since the stars are

so far away, the effect is small and can only be

detected using telescopes.

As though seated on a

royal throne, the Sun

governs the family of planets

revolving around it.

Nicolaus Copernicus

Earth in

January

Sun Near

star

Earth in July Distant stars

Apparent position