Testing the gravitational inverse-square law
E. G. Adelberger, Blayne R. Heckel, C. D. Hoyle · Physics World · 2005
Nothing seems more certain than the “fact” that there are three dimension of space. But can we be sure that there are only three dimensions? Imagine a tightrope walker balancing on a cable high above the ground. To the tightrope walker the cable is effectively a 1D object, because he only needs one coordinate to specify his position as he walks back and forth. But an ant, for instance, sees the cable as a 2D object, because it can crawl along and also around the cable.