38 NICOLAUS COPERNICUS
was not in motion. Yet, despite
his demolition of the evidence for
the Ptolemaic system, Oresme
concluded that he did not himself
believe in a moving Earth.
By the beginning of the 16th
century, the situation had become
very different. The twin forces of the
Renaissance and the Protestant
Reformation saw many old religious
dogmas opened up to question. It
was in this context that Nicolaus
Copernicus, a Polish Catholic canon
from the province of Warmia, put
forward the first modern heliocentric
theory, shifting the center of the
universe from Earth to the Sun.
Copernicus first published his
ideas in a short pamphlet known
as the Commentariolus, circulated
among friends from around 1514.
His theory was similar in essence
to the system proposed by
Aristarchus, and while it overcame
many of the earlier model’s failings,
it remained deeply attached to
certain pillars of Ptolemaic
thought—most significantly the
idea that the orbits of celestial
objects were mounted on
crystalline spheres that rotated in
perfect circular motion. As a result,
Copernicus had to introduce
“epicycles” of his own in order to
regulate the speed of planetary
motions on certain parts of their
orbits. One important implication
of his model was that it vastly
increased the size of the universe. If
Earth was moving around the Sun,
then this should give itself away
through parallax effects caused by
our changing point of view: the
stars should appear to shift back
and forth across the sky throughout
the year. Because they do not do so,
they must be very far away indeed.
The Copernican model soon
proved itself far more accurate than
any refinement of the old Ptolemaic
system, and word spread among
intellectual circles across Europe.
Notice even reached Rome, where,
contrary to popular belief, the
model was at first welcomed in
some Catholic circles. The new
model caused enough of a stir for
German mathematician Georg
Joachim Rheticus to travel to
Warmia and become Copernicus’s
pupil and assistant from 1539.This 17th-century illustration of the
Copernican system shows the planets
in circular orbits around the Sun.
Copernicus believed that the planets
were attached to heavenly spheres.It was Rheticus who published
the first widely circulated account
of the Copernican system, known
as the Narratio Prima, in 1540.
Rheticus urged the aging priest
to publish his own work in full—
something that Copernicus had
contemplated for many years, but
only conceded to in 1543 as he
lay on his deathbed.Mathematical tool
Published posthumously, De
Revolutionibus Orbium Coelestium
(On the Revolutions of the Heavenly
Spheres) was not initially greeted
with outrage, even though any
suggestion that Earth was in motion
directly contradicted several
passages of Scripture and wasSince the Sun remains
stationary, whatever appears
as a motion of the Sun is due
to the motion of the Earth.
Nicolaus Copernicus