A TV series called the sliders introduced the concept of parallel universes discovered by a university student Quinn Mallory experimenting with antigravity in his basement in an attempt to revolutionize heavy lifting.

Instead he got more than he bargained for. His experiment produced somthing else. It had managed to reproduce the holey grail of cosmology an artificial wormhole. A wormhole is a theoretical gravitational pull right in the center of a black hole ( called a singularity ) shrinking space into a deep well. The vertical well links with another black hole across the other side of the universe creating a space tunnel.

In the case of the sliders the experiment created a portal to different dimension earth's. They were the same earth's same times only alternate time line evolutions. Each earth was ninety percent identical, the reaming ten percent was what made each dimension different. The British TV series Doctor Who got in on the act is an example of the concept. Several episodes played it out with a double of himself and one of his assistance's double from a parallel universe reminds us the world of sci-fi is full of parallel universe stories.

In theory the dimensions are alternative evolutions. For this dimension ( our world at lest ), at the time of the last ice age there was an instinct species called Cro-Magnon men and Neanderthals living along side humans.  Neanderthals and Cro-Magnon men had pronounced brow ridges while humans looked modern,

Our dimension we are the only species to survive. In the world of different dimensions means there should be alternative evolutions. There should be  many alternative none humans, Neanderthals, Cro-Magnon combination that exist to this day. Imagine a dimension where Neanderthal or Cro-Magnon culture and technology exist today instead of humans.

In theory there should be identical DNA with a slightly different personality make up. In theory every possible circumstances decisions and  lucky chances from birth to death is playing out right now in many infinite Cro-Magnon men, Neanderthal and human parallel dimensions. Our world is only dominated by humans but many other dimensions only Cro-Magnon men or only Neanderthal earth's today.

In a human dominated dimension our world had played out Hillier's life the way all the Hitler biographies tell it like it. In many dimensions  histories Hitler's double's lives were very different  his exact DNA double but not necessary the identical personality trait as each other. There are millions of dimensions successful and talented Hitler artists. Many dimensions can potentially have famous landmark buildings and structures that bears his signature and styling often bearing his of his name and many case all over the world.

In the theory of many divisions to our personal time line history our doubles should be leading totally different lives than ours. Using Hillier as an example lead a totally different life in this world compared to an alternate life as a famous artist architect or some other profession in many many alternatives. There is a infinite number of alternate realities.

While some of us are single others are married with children in various different careers while others not famous and some are, while others are drop out nobodies all living at the same point in time. To clearly show in a extreme example of the different lives of us doubles lead the possibility of Hitler's family for example moving to America for a better life were part of the 1500 souls that went down with the Titanic.

There are many alternate Julius Cesizer  to Albert Einstein's. Heretically a lot of Hitler's doubles weren't so lucky to world war one. There is little a known story a Australian sniper serving in the Western front had Hitter dead in the cross hairs of his scope. Next second the sniper had to release his finger because Hitler had moved, There was no clear shot saving his life. 

Many Australian sniper doubles got him. Many others did not. In many ways, fate can dish out many complex lucky and unlucky escapes in many dimensions at the same time serving in the first world war. In other words as far as the dimensions of the cosmos  is concerned all the Hitler doubles were dead and alive at the same time.

It is the concept of a thought experiment thought up in this dimension, ( at lest ) by a German Physics called Schewdgener's cat that portrays a hypothetical odds of many of our doubles ( and when I say our doubles yes I do mean you and me ) are dead while others( like us and our doubles ) are still alive in the many other dimensions including you and me as doubles to the other dimension doubles to this day. Schewdgener's cat principle is a part of quantum physics entanglement theory.

The term entanglement in Quantum theory happens to be the very meaning of the word in context. Me and you and all our doubles lives are all entangled together by our DNA in the dimensions of the cosmos.

Particles of the atom are identical clones throughout the entire universe, no matter were they are. Atoms of the sun are the same atoms in every other stare even clear across the other side of the universe. A clear idea liken to a dozen identical basket balls in one shop identical balls elsewhere in others all over the country. They are all the same no matter where they are.

Theoretically what an atom does this side of the universe there are cloned particles clear across the other side as well. All the characteristic behavior of every particle the entire universe is uniformly the same. What atoms do in this side of the galaxy atoms are equally working clear across the other side too. 

This means odds of an action in this side of the universe has a similar chance of a similar effect the other side. The word  entanglement describes the entangled lives of the atoms of the universe including us and our doubles entangled with us.

Enchantment theory came about from a simple question. What if a person in our world changed our worlds history traveling back to world war one making sure Hitler was killed then returned to the present? What would happen to the timeline we remember? Where does all the historic events remember go? There is a disastrous clash of time lines.

Another time traveler goes back to the past to make sure Hitler lives altering the time line again. Theoretical in the world infinite possibilities our time line can be changed time and time again. Our time line is not fixed but variable. It can be changed to different time lines as many as infinite.

One scenario I can think of is like a computer reboot that happens in each dimension. If the stored operating system memory recovery sequence is anything to go by, the person might be creating a parallel dimension instead of the original time line. The original keeps it's original time line that was meant to be. The original Hitler is not killed in the original while a reboot copy started a new time line at the point Hitler died carrying on leaving him dead and our own Hillier alive.

This my be what prevents cranial time traveler interference. From our point of view of a visitor from the future is different from the visitor's point of view of us as a person from the past. So what influences your decisions in the present will depend on the view we are a person of the past. The person of the future is changing the past point of view but ( as you won't know it ) you will be changing the future of what you was supposed to have done the changing your fate to a new angle to your life you was never supposed to have done.

The view point of the person seeing the present as his past and the future visitor as things that haven't happened to us yet  are in parallel with each others.

The pilot of the sliders gathered together Mallory's professor Maximilion  Atorio, his part time coworker Wade Wells and a washed out rhythm and Blues singer Rembrandt Brown accidentally swallowed up by the wormhole when Mallory and the others slid it. The polite laid out the plot the coordinates to get back home became corrupted trapping them in in a endless series of sliding from world to word in the hope they will find the right path back.

Thus began the on going adventures of the sliders sliding from one world to the next hopping the next one would take them back home all throughout the series. In the course of their travels they meat there fair share of their doubles.

Operating on the principle we can imagine thousands of different outcomes for the Titanic. It missed the iceberg in many worlds.  Many worlds worlds the politics at the turn of the twentieth century was different than ours as we know it so world war one couldn't break out. Many worlds was no history of the Titanic what so every.

It has been proven ( at lest in our world ) the Titanic was solidly built. Investigative teams found the Titanic was structurally sound. It has been concluded no ship could ever have survived that much stress compared to other ship disasters floundering and sinking in far better better conditions.

In the many worlds the sliders visited the Titanic may not have existed at all but on many other worlds events leading up to the sinking had to have varied from world to world. The crew and passenger manifests and their doubles had to have varied from world to world too from different captains to crew members. The universes is a world where this world is just one of many entangled with other dimensions in which ships don't exists and ships that exists at the same time.

In some worlds the Titanic could have easily barely squeezed close by in a close call sailing harmlessly on leaving a small foot note in those world liner histories. Many other alternate Titanic histories may have gone down were the water tight doors did their job keeping the ship afloat for days. Passengers safely rescued to other ships using the Titanic's life boats ferried to other liners and merchant shipping that came to the rescue. That is one hell of an alternate famous way for a famous ship to go.