On Wednesday, August 13, 2014 6:43:55 AM UTC-4, Doug Miller wrote:
....
Related thought experiment: suppose you have a string wrapped
tightly around the surface of the earth. How much longer does that
string need to be, if you want to put it on one-foot-high
standoffs all around the planet?
....
About 8" (two feet / pi).

Related thought experiment: Suppose you have a mile of railroad track. Suppose it gets really hot and the track expands (in length) by one inch. Suppose that, due to the expansion, the track buckles in the middle, forming an isosceles triangle. How high will the bump in the middle be?