The Copenhagen Multiverse
Subatomic matter behaves very differently to larger masses. One example of this estranged behavior is called the 'double slit experiment' introduced by physicist Thomas Young in 1805. This experiment consists of a machine that shoots a beam of photons, electrons or even atoms towards film screen - but before the particles reach the screen and leaves tiny marks, it needs to pass through either an upper slit, or a lower slit that are closely separated. Each slit can be closed, or both can be left opened by the choice of the observer.
Now, when the beam of particles hit the screen, you would suppose the particles had to pass through either the upper slit or the lower slit, yes? However, the strange thing is, is that if you close down one of slits, more particles reach the screen than if you left both slits open! How can this be? You would imagine more particles reaching the screen if both slits were opened - but this is not the case. One strange answer came about. The particle wasn't a pointlike particle at all. It acted as though it were a wave! If one uses the wave description, the problem seemed to go away. We know how waves act in the sea, and this also means that the particle will take these attributes on board. A wave could reach both slits at the same time - and just like a wave coming into contact with two openings, the wave can split into two smaller waves, one, as i am sure you can guess, in each slit. If the two waves travel different paths, they can be made to interfere with themselves after passing the slits; in doing so, less waves reach the screen. If one slit is only open, the wave will travel through the slit, and, just like a wave hitting the shore, it will hit many places simultaneously on the screen - thus hitting more places with one slit open, than having both slits open.
However, the particle wasn't only just a wave - after all, when it hit the screen, it left a tiny 'pointlike' mark. Somehow when the wave hit the screen, it hit many places on the screen as dots. Thus, a new description had to made for a particle that traveled through space as a wave, and finishes its journey as a single object - this description has been come to be called the 'wave-particle duality.' The particle therego was in fact a wave and a particle simultaneously. Why did the particle act as a wave? Well, at first, physicists thought that the wave was a product of the human mind - it wasn't real, and it was just a means for us to keep track of experiments. The wave became to be called the 'quantum wave function.' This was a wave of possibilities. The wave probability enables us to calculate the possibility for a particle and its path, location, spin, orbital reference, Ect. The wave spreads out over space, and resembles likelihoods, not actualities... or does it?
In 1957 physicist Hugh Everett the third, came up with a rather bizarre conclusion concerning the wave function. His idea was that if the experiment says that the particle passed through both slits at the same time, then both particles, the one traveling past the upper slit, and the particle traveling through the lower slit, must both exist. Question is though, how and where does this extra ghostly particle exist? The answer was parallel universes. Somehow, an identical particle existed in a parallel world; the wave represented the amount of particles it was composed of, thus one particle passed the upper slit and a particle passed the lower slit, and each 'branch', or universe, it was represented as a wave, having quite a real effect in each universe.
However, why should the particle be a wave and then suddenly become a particle again? It turns out that our universe, according to Everett, is constantly splitting and merging every time some measurement is performed or when something comes into contact with something else. Each time the universe split, it would represent the wave function splitting into as many possibilities as there where outcomes, and the merging would represent the universe becoming superimposed all over again. Thus, in the double slit experiment, when the particle moves through both the slits simultaneously, this represents the universe splitting, creating as many universes as the possibility allows - in this case, two universes - and the merging represents the pointlike dot when it hits the screen. However, it turns out that the experiment represents only two universes - yet, it turns out that our universe is in fact one in an infinite amount of parallel universes, all 'superpositioned' upon each other, like layers on a cake.
It is amazing, i think at least, that something so science-fiction like parallel universes can be taken rather seriously by top physicists today. The theme is almost unimaginable... just think about it - an infinity of universes - an infinity of earths for that matter, with an infinite amount of me's, and an infinite amount of you's - worlds were i exist, and worlds were you do not - worlds were you exist and i do not. Worlds that neither of us exist... worlds that are barren of life, and worlds with life more weird and wonderful than we could ever imagine. Worlds of paradise, and hell worlds galore!
And each universe is unique, as there maybe several outcomes to a certain event, but only one individual outcome is allowed in any single universe. Thus, whenever i flip a coin and observe what side it has landed on, i become apart of the splitting of the universe, and my body is projected into two me's - one in this universe looking and observing a heads, let's say, and another me in the 'newly born' universe observing a tails. However, this easy-creation of universes disturbs some scientists. The idea is, if you flip a coin in 100 tosses, you create something equivalent to 1,267,650,600,228,229,401,496,703,205,376 universe-possibilities real; that is a little over 10^30. If every 6 billion-odd souls on earth simply stopped to flip a coin a hundred times, you could imagine the amount of universes that would split off from our own. In fact, the parallel universe theory has undergone some variations over the years. Some scientists believe that not only is our universe prone to split, but all the parallel universes might in fact also split.
Matter in each of these universes permitted to contain matter, are in equal proportion, which is around 10^80 particles in each universe. However, this is where we tend to get a little confused - even though a particle, according to parallel universe theory, exists in two worlds as a wave in the double slit experiment, there is only one particle ever present whenever the universes merge! There will always be a single particle present, provided no one comes along and decided to observe the little particle, or a large electrical force pulls it out of its superpositioning - or simply, whenever anything comes into contact with something else; even in a tragedy.
It thus turns out that there are an infinite amount og universes, but only one outcome is allowed in any of them.
Neither would it do us any good to say that time passes at the same rate in each of these universes - that wouldn't be accurate at all. It would be like the differential time zones on planet earth - i will be asleep in one universe, whilst i am totally awake here and now. Some universes might be so similar to ours, the only quantum difference is that you might be wearing a red tie, instead of a blue tie... A universe with these differential time traits are called 'self-contained' time.
Now, not every physicist agrees with parallel universe theory - take for granted some of the best minds in the quantum mainstream, like Stephen Hawkings entertain the 'many world hypothesis,' instead of the 'collapse of the wave function.' The wave function permeates all of spacetime. Created by Erwin Schrödinger, the mathematical function would predict the infinite amount of possible locations or paths an atom can have; for instance, in the double slit experiment, the wave represents two paths - thus the paths are represented by the wave function. The collapse of the wave function is the sudden reduction in the value of probability. The idea, is that the world suddenly reduced to a single calculation - the wave is said to collapse - the usual way to describe the collapse, is to imagine a balloon being deflated.
Although, the collapse itself has been attacked by some physicists over the years, the most famous attack was by Albert Einstein - as you may know - he was highly critical of the conditions brought about by the simple act of observation - and it wasn't an isolated case... as he carried his displeasure for Quantum Physics right to his death. He also brought to our attentions, that quantum physics failed as a complete theory - it failed to explain how an observer comes to know something