Geocentric vs Heliocentric

helio + centric

of or relating to the sun + center

Geo + centric

relating to the earth + center

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

Nicholas Copernicus- Heliocentric model

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

moveGod made created everythingEarth is the center of god’s creation

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

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

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

Kepler

The orbit around the sun is elliptical rather thancircular as proposed by Galileo.