CC0 Usage Conditions ApplyClick for more information. About two thousand years ago, a Greek scholar named Eratosthenes used some sticks, shadows and math to calculate the circumference of the Earth.
“The cosmos is also within us, we're made of star-stuff. We are a way for the cosmos to know itself.” - Carl Sagan Compared to the Sun, how big is the Earth? What is a scale model and how does it help ...
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