A quantum string is a theoretical, one—dimensional wiggly little string that can exist in 11 dimensions, whatever that means. The string is the core idea of string theory, the most well—known crack at an overarching theory of physics that can explain both the quantum physics of the tiny world and the gravitational physics of the larger world.
A string is supposedly about 10^-34m long. That’s embarrassingly short. If the smallest neutrino were the size of the Sun, a string would be just 2 mm long.
But that doesn’t capture the intense smallness well enough. Let’s try this another way:
Imagine creating an Earth like ours, but the size of a marble. Now imagine that someone on that Earth does the same thing, making a mini-Earth the size of one of their marbles. And then someone living on that double-mini Earth does it again. And now, imagine that someone on that triple—mini Earth is playing the guitar. The guitar strings are the length of our world’s quantum strings.
Keishinrei 