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Re: [Phys-l] gravitational force



On 11/1/06, Karim Diff <karim.diff@sfcc.edu> wrote:

the surprising thing is
that most students think that
the radius of the Earth is very recent knowledge (most think it is less
than 500 years old)

and invariably ask how come people believed the
earth was flat if Eratosthenes
got it right ( or close enough) over 2000 years ago. From what I was
able to gather, the belief that the earth is flat is mostly a legend
invented in the 19th century as a put down of the medieval people
(Washington Irving is often mentioned as the main culprit).



My personal experience is that people believe this knowledge to be acquired
500 years or so because of popular stories about Columbus. As far as I can
tell, many people believe that Columbus's struggle to get support for his
westward mission was due to trying to convince the courts of Europe that the
world was indeed round. However, I understand that the struggle was
actually over the _distances_ involved. Using most estimates of the
circumference of the earth, sailing westward to get to the Indies was beyond
the capability of the sailing vessels of the time due to the length of the
voyage. Columbus believed the distance to be much shorter than most other
estimates and spent years (if not decades?) bringing people around to his
estimate. And of course Columbus was wrong with his estimate of the
distance/time of his intended trip.

--
regards
-Krishna

Krishna Chowdary
Department of Physics & Astronomy
Bucknell University