“For the observed difference in the shadow lengths, the distance between Alexandria and Syene had to be about seven degrees along the… — Carl Sagan Copy Share Image
I walk alone in the darkness and wonder how a person would begin to determine the circumference of the earth. I have… — Robin Sloan Copy Share Image
Eratosthenes's only tools were sticks, eyes, feet, and brains; plus a zest for experiment. With those tools he correctly deduced the circumference… — Carl Sagan Copy Share Image
Ten decimal places of π are sufficient to give the circumference of the earth to a fraction of an inch, and thirty… — Simon Newcomb Copy Share Image
Remembering that Eratosthenes of Cyrene, employing mathematical theories and geometrical methods, discovered from the course of the sun, the shadows cast by… — Marcus Vitruvius Pollio Copy Share Image
“Columbus therefore cheated on his calculations, as the examining faculty of the University of Salamanca quite correctly pointed out. He used the… — Carl Sagan Copy Share Image
