What Am I Looking At – Part II

“Eudoxus”

     by Aaron Clevenson

 

This is the second in a series of interviews with famous astronomers of the ages.  Our ultimate goal is to trace our understandings of the physical universe.  This month we are going to talk to Eudoxus around 360 BC.

 

NORTHSTAR:  Tell us a little about yourself.

EUDOXUS:  I am a Geometer.  I left my home in Cnidus in Asia Minor and I traveled to Plato’s Academy about 25 years ago to study with other great thinkers.

NORTHSTAR:  Tell us a little about the Academy.

EUDOXUS:  It is a wonderful and serene place, set amid a grove of sacred olive trees near Colonus.  Plato’s mentor, Socrates loved to sit amid the trees and think great thoughts.  It is located about five miles northwest of Athens.  Above the door is carved the inscription: “Let None But Geometers Enter Here”.

NORTHSTAR:  What is a Geometer?

EUDOXUS:  A Geometer is one who studies the Universe.  I believe that the Universe is comprised of abstract geometric forms.  The science emerged in Egypt along the Nile River.  Egyptian rope-stretchers would go forth each season after the floods to survey the land and determine property boundaries.  We have taken their basic thoughts and greatly elevated them to almost the level of a theology.

NORTHSTAR:  Tell us of your work.

EUDOXUS:  Shortly after arriving at the Academy, I undertook a pilgrimage to Egypt.  Egypt after all was the birthplace of geometrical wisdom.  There, I did research in geometry, but also applied it to the stars.  I build an observatory on the banks of the Nile and proceeded to map the sky.  I returned to the Academy and set about creating a model of the Universe.

NORTHSTAR:  Please tell us about your model of the Universe.

EUDOXUS:  Well, about a hundred years ago, Parmenides developed a model of the Universe that was a great sphere surrounding the Earth.  This was an improvement over the model of the Egyptians, because as we all know, a sphere is the most perfect of the geometric solids.  But our observations are much better than they were a hundred years ago.  To satisfy the empirical data that we now have, I have developed a far superior model of the Universe.  It begins with the Earth as a sphere in the center.  All educated Greeks know that the Earth is a sphere.  We can tell this by the shape of the shadow that it creates on the moon during an eclipse.  Around this I have made not one, but 27 spheres.  These spheres drag and pull at the spheres of the sun, moon, and planets and help us understand and interpret the minor aberrations that we see in their paths.  When you add to this their rates of rotation and inclination on their axes, my model very adequately represents the real Universe.

NORTHSTAR:  Do you have any plans to refine your model?

EUDOXUS:  No.  It very accurately describes the motions of the objects in the sky.  There is no need for further refinement.

NORTHSTAR:  Thank you very much Eudoxus, for sharing with us your model of the Universe.