Let me ask you a math question. If the equator is surrounded by a wire that is 1 m longer than the equator of the earth, how far is the gap between this wire and the equator of the earth? Think of the earth as a sphere. Suppose the circumference of the earth =2×pi×r, and the circumference of iron wire = 2× pi× r.

Then that circumference of the iron wire-the circumference of the earth = 2×π×R-2×π×R = 1,

That is, 2×pi×(R-r)= 1.

And (R-r) is the gap between the iron wire and the equator of the earth.

Therefore, r-r =1/(2× pi) = 0.159155 (m).