String Theory Review
As we studied in class, string theory essentially states that the most fundamental particle in the universe is a loop-like, one-dimensional string. These strings compose absolutely everything; the kind of stuff that a given string makes up is determined by the frequency at which it vibrates. String vibration is an essential part of string theory; as string vibrations determine what kind of stuff a given string represents, analyzing string vibrations can help us study the smallest of particles, and predict the existence of certain, previously-undiscovered particles (strings, like any other vibrating object, can only vibrate at certain calculatable frequencies, so the predictive power of analyzing string frequencies is well worth noting).
In Newtonian physics, particles combine like this:
In other words, they hit each other and travel off together. There is no point in time at which they are partially combined, at which an intermediate form of half-combined material exists. String theory, however, proposes a different model:
In this model, strings slowly merge together, to form a new, combined string. But there is a significant time where the strings are half-merged, so the reaction takes place over a significant period of time. This is consistent with predictions made by quantum mechanics, and by observations in the real world (the real world of particle accelerators, at least). This animation shows two strings actually combining, and then breaking apart again, as predicted by string theory: