Monday, May 19, 2014

Multiverse Theory: Time Travel

There is another way to create alternate universes: time travel.  Disregarding the high improbability of the human race actually achieving time travel through modern science, if such a form of transportation was achieved, it could mean time paradoxes could be created.  In this post I will describe what time is, how alternate universes could be created through time travel, and how time travel could be possible.

Time is commonly known as the "fourth dimension", as labeled by Albert Einstein in his theory of relativity.  It represents another point in space that can be used to locate objects, to tell where they were in the past and where they will be in the future.  Conventionally time is thought to be linear, an arrow originating from one point.  But time is now being seen as either a curved or straight line that extends infinitely in both directions.  This is due to Einstein's theory of relativity and the many origin theories of the world that say there is no true beginning or end of creation.  The most important thing to know about time is that it is bent by mass, and wherever it is bent, there is gravity.

If time travel was ever achieved, time paradoxes could be created which could result in alternate timelines (universes) that would either rewrite or branch off from the original timeline.  If, let's say, a man was able to travel back in time and prevent WW II from ever happening (how he does so is unimportant in this scenario) then history would be changed and two timelines - two parallel universes - would be formed: one where WW II never happened and one where it did -  and the man who split these two timelines would be lost in the old one and stuck in the new, unless he chooses to create another new timeline.  These two alternate universes would be able to coexist with each other if we choose to believe in the theory of Hilbert space.  Another outcome of this, however, would be that the original timeline that the man changes by preventing WW II is taken over and replaced by the new timeline; in this way there would still be only one existing universe, though it is inherently different from the preexisting one.  One last outcome that could happen is that the photons that make up light would prevent anyone from changing written history because they prefer one consistent timeline; this means that even though time travel is possible, no one cannot rewrite it: everything that has happened or will happen cannot be changed.

Now for the most important question: how can time travel be achieved?  Travelling through "wormholes between points of space-time" is one theory.  Flying around an infinitely long cylinder that's matter "is 10 times the mass of the sun", or a black hole, faster than the speed of light.  Bringing cosmic strings together to warp space and time.  Creating "a doughnut-shaped hole enveloped with a sphere of normal matter" and applying intense gravitational forces to bend space-time in a loop; then a person would run around this doughnut hole and they would travel further back in time with each "lap".  Unfortunately, wormhole have yet to be even observed by scientists and they theoretically could only allow very small particles through; travelling faster than the speed of light is questionably physically possible, seeing as how that object travelling that fast would have "both infinite mass and a length of 0"; cosmic strings have yet to be observed as well;  and controlling gravitational forces powerful enough to bend space-time in a loop would be extraordinarily difficult and dangerous.

I myself have an alternate theory for how we may "time travel".  I say "time travel" within quotation marks because there is a theory that there is only one, infinitely vast universe all within our Hubble volume.  The
rules of probability state that, if this were true, there would be multiple, identical configurations of matter spread out all across space.  This would mean that somewhere out in space there is another Earth.  If we as humans somehow achieved interstellar travel, we could eventually find another identical Earth comparatively premature to our own.  In this sense we would not be bending space-time, but we would be travelling into our own past by visiting a world identical and younger to our own.

This post truly and finally concludes my series of posts on the multiverse theory.