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The Sun Centered Universe
Jeremy Benton
Amy Kidd
Intro
Reasons for Theories of Geocentricity
• Plato (4th Century BC)
– Theories of the universe included
• Perfect Circles
• Based on simplicity
• Either a mathematic or geometric model of universe
Reasons for Theories of Geocentricity
Cont.
• Eudoxus (student of Plato’s)
– His theories were more developed, and they
included:
• Geocentricity – one of the first scientists credited with
these ideas
• Crystalline spheres – trasnparent spheres that lie
between the earth and the stars that account for all
motion in the universe
• He came up with 26 different crystalline spheres to
account for all the motions of the universe.
Reasons for Theories of Geocentricity
• Hipparchus
• Earth centered
• Deferents and Epicycles to explain ideas of retrograde
motion
Reasons for Theories of Geocentricity
• Claudius Ptolemy of Alexandria (150 AD)
– Utilised the geocentric model, that earth was the
center of the universe, to predict with far greater
accuracy the motions of known celestial bodies. This
reinforced the idea of geocentricity over heliocentricty
among other astrolgists of the time.
– His work many also linked to the bible. Although the
bible doesn’t explicitly say that earth revolves around
the sun, many interpreted certain verses to mean so,
thus creating a link between science and theology (the
study of the bible).
The link between astrology and
theology
• According to the bible man is God’s greatest creation;
therefore the earth must be the center of God’s focus.
• Anyone who disagreed or didn’t believe these ideas
was often severely punished. For hundreds of years,
going against the Catholic Church had huge
consequences that ruined lives and careers.
– “After all, if we were dwelling on one average planet,
rotating around one average star, in one average galaxy in
an infinite Universe, how could we be the sole focus of
God’s attention, and why should His only Son be sent just
to this middling planet, as the Bible suggests?” (Thompson,
1988)
Heliocentricity Catches Up
• Copernicus (1543)
– He was the first to develop a valid heliocentric
model of the solar system.
– In his model he included ideas such as:
•
•
•
•
•
A sun-centered solar system
Earth and all other planets revolve around the sun
The stars are actually far away from us
The earth has more than one motion
All previous observed motions were due to the motion
of the earth
The Consequences of Such a Theory
• Due to his ideas challenging the predominant
view of that time, it took 150 years before his
theory was actually accepted.
• His book De Revolutionibus Orbium Coelestium
was placed on the list of forbidden books because
it challenged the dominant view held by the
Catholic Church.
• At first many rejected it simply because they were
afraid of how this view could challenge other
scientific theories of the time, and thus create
chaos.
• His theory of heliocentricity was the first of its
kind to match the accuracy of Ptolemy’s
geocentric theory.
– He was just as accurate, but no more accurate
than Ptolemy was.
– He also insisted that Ptolemy’s model was not
“pleasing to the mind’s eye”.
Other challenging theories of the time
• Tycho Brahe- 1572
– Sun is center
– Sun revolves around Earth
– Other planets revolve around Sun
• Theory not accepted by anyone
Other challenging theories of the time
• Johannes Kepler (Assistant of Brahe)
– Took both Copernicus’ theory and Brahe’s
observations and used them to add the the
theories of heliocentricity
• Earth must be a moving object
• Earth speeds up the closer it is to the sun
• He discovered this from his work studying Mars
• Galileo – 1600’s
– Galileo also believed in the theory of
Heliocentricity because of his study of Venus’
phases of the moon
– If the sun and planets were both orbiting earth, it
would be nearly impossible to have a shadow on
Venus at all times, as he observed.
– The Church had many issues with Galileo’s work
over the years. So much so that they put him
under house arrest until he died.
Impact on Science/society
• The rejection of the geocentric model allowed for
the modern field of physics and astronomy to
develop
• Scientific views regulated by the Church limited
science’s potential to progress
• It also allowed for accurate astronomical models
to be developed thus allowing for flight, space
travel , satellites etc.
• Today, the heliocentric model is accepted almost
without debate
• Because of the heliocentric model of the
universe, we are now able to do things like go
to the moon, or, possible sometime soon, to
Mars!
A return to old beliefs?
• With the proposal of the Theory of Relativity,
it can be said, in a particular way, that the old
geocentric model is not necessarily invalid, for
according to it it cannot be determined which
of two bodies is rotating around which one.
Bibliography
• http://intro.phys.psu.edu/class/p001projects/
project1/sp12projects/9physic_1_project.pdf
• http://apologeticspress.org/apcontent.aspx?c
ategory=11&article=1151
• http://gbgm-umc.org/umw/bible/wv-nt2.stm
• http://hypertextbook.com/eworld/geocentric.
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