Post by intrigued on Mar 20, 2018 21:52:36 GMT -5
I think a lot of people have missed the boat on the PU-TU connection that can be easily explained using String Theory. Allusions to String Theory can be found in several places in the movie. For instance the fixation on the number 8. Eight and infinity (sideways 8) are common in string theory equations. Also slinkies are used in modeling string theory behavior and Donnie is curiously holding one when talking to Professor Monitoff about time travel.
In a nutshell, time can have string-like properties. Imagine a string connected to each index finger of both hands and then extending your hands until the string is taught. This is our normal conception of time (unbent by extreme gravity associated with things like black holes, worm holes, etc). So under "normal" circumstances, the string is taught, time is linear, and the shortest distance to each two finger follows the path of the string. This path is the PU. However, in certain conditions (e.g., wormholes) the fingers can move closer to each other, creating slack in the string and hence a loop. The loop is the TU and the PU simply takes the shortest path by traveling across the top of loop where both sides of the string still touch. When the loop first forms the TU and PU are identical. Depending on the size of the loop, a considerable amount of time can pass in the TU before it reintersects with the PU while very little time has passed in the PU since it "jumps" the loop. The way the movie speeds up and slows down in certain scenes reflects this elasticity in time. However, eventually the string becomes taught again destroying the TU. When this happens any contradictions between the TU and PU must be resolved or else the time-space continuum can be disrupted.
Since it takes incredible gravitational force to create a TU (the wormhole), objects from the PU can be pulled into the TU (and upon TU destruction from the TU to the PU). In Donnie Darko, the object pulled through shortly after the creation of the wormhole/TU is the Artifact and the person closest to where the artifact impacts is the LR (especially if it falls on that person). Now, the Artifact no longer exists in the PU and has a twin in the TU. This is the temporal contradiction that can disrupt the space-time continuum at the end of the TU unless the LR can return the artifact to the PU. Since much more time passes in the TU than in the PU, the affect of the Artifact is much greater in the TU. In the PU, the disappearance of a jet engine for a few seconds or minutes is much less likely to alter events than the appearance of duplicate jet engine in the TU for say 28 days. So what happens in the TU is more important to the survival of the space-time continuum.