Re: Who claimed first that the earth was round?

Dear Vicki,

     The fact that the Earth is round has been known for thousands of 
years.  Like all such facts known since ancient times, determining who 
claimed it first is a tricky task.  Credit usually goes to the 
civilization that first wrote down the idea.

     And in this case, that civilization is the Greeks, one of the first 
to write down their philosophical musings for the ages.  The Pythagoreans, 
to be exact.  Now, Pythagoras lived from roughly 560 to 460 BCE, and was 
both a mathematician and a mystic.  He was founder of the Pythagorean 
brotherhood, a group of fellow mathematicians and philosophers who thought 
about a wide variety of subjects, trying to link philosophies to ideas 
about numbers.  They are best remembered for introducing the Western world 
to what is now known as the Pythagorean theorem, that the sum of the 
squares of the two shorter sides of right triangle add up to the square of 
the longer side (see http://plato
.evansville.edu/comments/beavers/000002.htm for more on the 
Pythagoreans).

     History records Pythagoras as being the first to claim that the Earth 
was round (see The Encyclopaedia Britannica, search for "Astronomical Theories of 
the Ancient Greeks").  However, it is difficult to determine whether he 
actually did or not.  

     Whenever any one of the Pythagoreans wrote something down or told a 
story, they tended to express their ideas as "the master (Pythagoras) said 
that...".  So whether Pythagoras himself or one of his order first came up 
with a round Earth will probably never be known.

     Given that, why did they think the Earth was round?  Well, the Sun 
and the Moon where both round, and in a way spherical is the simplest 
three dimensional shape.  Therefore (Pythagoras or one of the 
Pythagoreans) reasoned that the Earth should probably be round as well.

     That really is the start of the story.  Pythagoras may have claimed 
that the Earth was round, but he didn't really prove it, and he certainly 
didn't realize just how big it was.  I suggest again looking in 
The Encyclopaedia Britannica under "Earth the spherical era" for a 
list of articles describing how the size of the Earth was eventually found.