GeOcEnTrIc ThEoRy

Definition: A theory created by ancient Greek astronomers that says that the Earth is the center of the universe and that the sun and the planets revolve around us.

Details:

~ The Geocentric theory is no longer an accepted theory in science.

~ No one thought the Earth was moving because no one could feel it in motion.

~ The Sun, Moon, and many other objects appeared to be rising and setting in a circular motion      

~ around the Earth, so everyone thought that they must be revolving around us.  

~ Astronomers observed the planets moving in a retrograde, or looping, path in the sky.  To   ~ explain it, astronomers said that the planets were revolving in epicycles, smaller orbits

~ along the regular larger orbit.

~ The Greek philiosipher Ptolemy was one of the earliest known people to record the theory that ~ Earth is at the center of the universe.

The first picture shows the Earth being at the center of the universe.  It shows the sun, Jupiter, Mars, Mercury, Venus and Saturn all revolving around the Earth.

The second picture shows a planet revolving around Earth on an eliptical path.   It also shows the planet revolving in a smaller orbit while moving in it's larger orbit around Earth.  This smaller orbit is called an epicycle.  It is what the Astronomers back then used to explain why the planets seemed to move in a retrograde, or a looping, path in the sky.

SO WHAT??? SECTION: So the question is, Why do we need to know a piece of ancient history? Well, the simple answer is, to learn for the future, you must remember the past.  To learn from your mistakes, you have to remember them.  Today we think that it is stupid to think that the Earth was at the center of the universe, but back then it made since for the Earth to be at the center from observations that the scientists of the day made.  What if we forgot our current knowledge of science, than we could go back to believing that the Earth was at the center of the universe, no problem.  It may sound stupid, and you may be sitting in your chair thinking that it would never happen, but if we don't remember that we once thought that Earth was the center of the solar system and that we were proven wrong, there is nothing stopping us from going back to believing that Earth is at the center of the universe.  Stranger things have happened!

Citations

Web Pages

"Geocentric Theory." Science Encyclopedia Vol. 3. 2008. 9 May 2008 <http://science.jrank.org/pages/2999/Geocentric-Theory.html>.

Link to Page

http://science.jrank.org/pages/2999/Geocentric-Theory.html

Books

Pasachoff, Jay. Science Explorer: Astronomy. Boston, Massachusetts: Prentice Hall, 2005.

DePree, Christopher and Axelrod, Alan. The Complete Idiot's Guide to Astronomy: Third Edition.

          U.S.A.: Marie Butler-Knight, 2004. P. 24-25

Exline, Joseph et al. Science Explorer, Earth Science. Needham, Massachusetts: Prentice Hall,

          2001. P. 671.