2. helio + centric
of or relating to the sun + center
Geo + centric
relating to the earth + center
3.
4. Ptolemy’s Model
• Geocentric model or Ptolemaic model
• Greek philosopher
• Earth was in the center, sun and other
planets revolved around it
• It wasn’t his original idea he
based it on ancient Greek observations
6. The existing belief’s-
• Julian Calendar, which showed errors
• accepted and followed Ptolemy theory of Earth being the center of
universe and the sun and other planets revolved around it
• Other beliefs-
if earth rotated around the sun, we will spin off into space
earth was heavy, while stars were light and fiery, so how could earth
move
God made created everything
Earth is the center of god’s creation
7. Nicholas Copernicus- Changing Scientific
Ideas
• Church felt that the Julian Calendar was inaccurate
• Copernicus was assigned the job of fixing the error
• through his observations, found out that earth revolved around the
sun and sun was stationary
• Pope gave him permission to publish his findings
• he had opposition from protestant reformers like Martin Luther and
Calvin
• his book “On the Revolution of Heavenly Bodies” was published in
1543
8. Galileo (21 years after Copernicus’s death) –
Contributions to Science
• based his discoveries on scientific observation and
experiments
• experimented with pendulums, designed adjustable
pendulums that doctors could use to measure pulses
• invented first telescope, made observation and proved
Copernicus was right
9. Galileo
• Church condemned him and tried him for heresy
• published “ The Starry Messenger and Dialogue on the
Two Chief Systems of the World –Ptolemaic and
Copernican”
• his publication and Copernicus’s publications were
placed on the Index of forbidden books by the church
