Quote:
Does it really require that the strings be infinite in length?


Gott says they do; but as you know, I tend to suspect interpretations of infinity, even by experts. smile

I believe the estimated mass of a cosmic string is about 4 x 10^16 tons per inch. Initially I had difficulty imagining how two such massive objects could pass close to eachother, because of their enormous gravity. However, Gott is of the opinion that their gravity would be cancelled out by their tension.

This leaves me wondering how a string could be responsible for gravitational lensing.

There never was nothing.