You might think the modern way to measure the radius of the Earth is to just look it up. Not so fast. Really, the fun isn't in knowing the answer; the fun is in getting the answer.

R is the radius of the Earth. Let me make one assumption -- that the arc length in the diagram (like s 1 ) is essentially the same length as the straight-line distance ( x 1 ).

IN a paper entitled "The Story of Newton's Inverse Square Law and his Use of a False Radius of the Earth" (J. Brit. Astro. Assoc., 50, 2; 1939), John Miller states that the story of Newton's ...

How an ancient Greek mathematician calculated the Earth's circumference. In the mid-20th century, we began launching satellites into space that would help us determine the exact circumference of ...

The Schwarzschild radius for the Earth is approximately one inch, meaning that you could squish the entire mass of the Earth into a sphere the size of a basketball and still not have a black hole ...