Thanks for clearing that up. It will certainly help me understand my current readings (though I am not reading Greene, that is where most of my knowledge has come from).
But our immediate perception of reality is so limited that it would be utterly conceded to consider other orders of magnitude "irrelevant". Things as small as that can not be simply disregarded due to their inferiority of size. They still affect us constantly.
Also, I do not understand why they suppose the existence of superstrings resolves the problems between quantum mechanics and general relativity. It is considered to be a unifying theory, that seems to imply that superstrings do quantize gravity. But that would mean that strings composed...