The main idea of time travel is simple. Realize a problem, go back in time to stop it, and voila! The human resistance against autonomous cyborgs becomes inexistent.
Trying to understand the science behind time travel, however, is asking for a headache especially when compounded with the paradox problem. For example, what if a man receives plans for a time machine from a stranger, fixes the continuum for his benefit, and goes back in time to tell his past self about it? Under this scenario, who really invented the time machine?
Theoretical physicist and futurist Dr. Michio Kaku refers to this as the “paradox of the man with no past.” In the example above, the stranger that gives the man the plans for a time machine is the future version of that man. By manipulating the very fabric of time and space, the man creates an indefinite loop at a point in his life.
How time travel actually works, however, is an even harder topic to discuss. H.G. Wells popularized the idea of the time machine, but pop culture grew too focused on the how, not the why. It transports you into any timeline, but why do such a thing? Does it influence the state of quantum particles or related matter?
Such explanations are secondary for time travel movies. Watch movies online for free and relive the fascination for this never-ending topic.