48 The Poetry of Physics and The Physics of Poetry
universality that our modern theory of gravity eventually developed. At
this stage, however, gravity is strictly local; there is no gravitational
interaction between the various heavenly bodies. Their circular motion as
well as their rotation about their axis is regarded by Copernicus to be a
result of their spherical shape. No further explanation is required.
Copernicus was unable to convince his contemporaries, however,
with these arguments. He was also unable to reply satisfactorily to some
of the objections they raised such as the claim that the rotation of
the Earth would literally tear the Earth apart because of the centrifugal
force and the claim that the rotation of the Earth from west to east would
imply a continual wind from east to west. The eventual acceptance of his
theory would require the downfall of Aristotelian physics that future
observations and experiments finally brought about. In the intervening
period, however, there was still a dedicated band of followers supporting
the Copernican point of view.
In addition to scientific difficulties alluded to; the heliocentric
viewpoint also gave rise to philosophical and theological difficulties. It is
ironic that at the same time the Church adopted the Copernican length of
the year as the basis of the Gregorian calendar reform of 1582, they were
condemning the Copernican worldview because it conflicted with
Scripture; for it is written that the Sun rises and the Sun sets. Even
though it is now more than 350 years since the acceptance of the idea
that the Earth moves and the Sun stands still, we still refer to the Sun
rising and setting.
The objection of the church went much deeper than this Scriptural
conflict, however. The crucial problem was the role man played in the
new Copernican universe. In the old Ptolemaic system man was at the
center of the universe with the heavens rotating about him for his
pleasure. It was too comforting a worldview for the egocentric spirits of
the Renaissance to give up without a struggle. The idea of hurtling
through empty space on the space ship Earth is an idea that appeals to
our age, but to the thinkers of Copernicus’ time, on the other hand, it
was a frightening thought.
Travel through empty space appealed to one man of this age,
however, as is illustrated by the poem L’Envoi by Giordano Bruno.
Who gives me wings and who removes my fears
Of death and fortune? Who inflames my heart?
Who breaks the chains and makes the portals start
Whence but a rare one, freed at last, appears?