This post is only going to be a superficial discussion and isn't going to explain anything in any real depth. I'm trying to simplify advanced quantum physics in the best way a "lay" person can.
In 1957, Hugh Everett introduced the idea of branching universes to solve a problem we encountered regarding seemingly random choices that the elements of the universe (waveforms in particular) when observed. Sometimes light appears as a wave, sometimes as a particle, and there is no way to know which a head of time. Everett suggested that the light doesn't make a choice when is it forced into one form or the other. It is always both a wave and a particle. The Universe branches into two each time the light is observed and forced to make a choice. In one Universe, you observe light beam taking on wave behavior. In the other Universe, another-you observes the light take on a particle behavior. Thus, the idea of branching Universes says that a two Universes are created every time a choice like this is made. There's a certain bit of faith required to believe this, but pure math doesn't lie, right?
The challenge
Now, I'm no physicists. I'm not going to challenge the math that goes into this notion. It's been tested many times and found to be sound. However, math is nothing more than a numeric language that we created ourselves to parse out elements of the Universe to understand it in our terms. Keywords being "our terms".
Everett's assertions about branching Universes (or Many-worlds interpretation, as it is formally called) are based on time being both linear and two dimensional at the same time. Each branching Universe is 1 dimensional, created within 2 dimensional time, like branching lines being doodled on a piece of paper. Well, that means it could be said time is 1.5 dimensional. I know many physicists will cringe at my interpretation of branching Universes. However, at least from an intellectual point of view, this seems to me to be a reasonable simplification. My point is the the concept of branching Universes offers an unnecessarily complex and convoluted explanation for something as simple as a beam of light acting one way instead of another.
Spontaneous creation of matter and energy?
Another problem I have with branching Universes is this. Where is all the infinite energy coming from to create all these infinite branches? Infinite energy is the same as infinite mass (E=mc2). If the Universe really started off with all of this infinite energy, it would have immediately collapsed back on itself, never to grow in the first place. Or, if the energy didn't exist at the Big Bang, there's no mechanism now that can continuously double the energy within a Universe to spawn new versions of itself. Thermodynamics has yet to be disproved by quantum physics.
Why is gravity so heavy?
Yet another problem. If gravity exists outside of the Universe, as current understanding quantum physics now suggests, it would be impacted by the creation of new branches of the Universe. As such, even if infinite energy is being created on the fly (as opposed to being there at the start of the Universe), gravity would weaken so rapidly, its decaying influence on this Universe could be readily measured and would likely lead each Universe to fly apart to nothingness shortly after the Big Bang. There wouldn't be enough gravity to form a single dust particle, let alone entire galaxies.
Every point in the Universe knows about every other point, 13 billion light years away?
One more problem? Sure. For entire Universes to be created instantly and constantly by the actions of a single particle or waveform in a highly localized point, every bit of energy, every particle, everything that exists would have to be instantly duplicated. These means that every bit of energy, every particle, everything in existence would have to be in instantaneous communication with every other bit of energy, particle and every object in the Universe, 13 billion light years across! This creates a new problem! If the action of every particle in the Universe has the ability to replicate the entire Universe, the information of the Universe has to be immediately available to all points within the Universe at the same time. But if the Universe is constantly branching, there is no preferred frame of reference from which the Universe can be infinitely replicated! There's no sorting mechanism to give one choice a preference over another when they happen at the same time. This leads to yet another problem.
Branching causes information bottleneck
The very act of infinitely and instantly replicating the Universe would create huge gaps in information on whatever the current state Universe is in. Things happen simultaneously all the time. How are quadrillions of simultaneous actions supposed to be instantly reconciled to instantly form quadrillion x quadrillion Universes? Some suggest that the ends of the Universe (whatever is just beyond 13 billion light years in any direction) may already be out of touch with each other. This would make the Universe impossible to instantly resolve to form all of these simultaneous branches. Even if all information about the Universe is known to all points in the Universe at any given instant, there would be a measurable bottleneck of the branching activity. Time would slow down at an increasingly observable rate.
2D Time makes branching unnecessary anyway
Here's the kicker. If the Universe is 1 dimensionally branching within 2 dimensional time, then time is already considered 2 dimensional. If time is 2 dimensional, then there's no need for the branching to take place. If the Universe is a waveform in 2 dimensional time, the objects within it are smeared across this these two time dimensions. We are simply seeing a 1 dimensional view of our Universe intersecting with 2 dimensional time.
Ball passing through a plane acts the same as our view of time
This is similar to a 3 dimensional ball that passes through 2 dimensional plane. As the ball passes through the plane, an observer on the plane simply sees a line that grows, then shrinks. He doesn't see the ball itself. Depending on where the ball intersects the plane, the observer sees a shorter or longer line (even just a point). Any measurement of the line is just as valid as any other, but only the portion that intersects the plane can be measured at any one time. So, this is also true of the Universe if time is 2 dimensions, and the Universe is a waveform that intersects it at different points. We simply see different view points of the same event each time we make an observation. There's nothing random about the observations! We just cannot see the whole shape in our limited view!
We aren't creating new branches of the Universe when the Universe "makes a choice". We are simply observing where our Universe is intersected by 2D time!
When we observe something that forces the Universe to "make a choice", it's not random. We are simply observing which portion of our Universe (or the element being observed) is currently intersecting within the 2 dimensional time. This doesn't mean that there aren't parallel Universes that resemble our own. It just means that those Universes have been there since the Big Bang (not branching), using a measurable portion of the Big Bang's energy for their formation, just as our Universe has.
To be clear, I offer the above as a notion to point to other interpretation of Quantum Physics. It's not meant to be the final word on anything, nor does it represent a tightly held belief of my own. I certainly haven't done any math to back any of this up. However, I do believe there are physicists that are already moving along similar paths of reasoning, so I'm trying to get the word out as the concept of branching Universes has been gaining momentum in recent years with very little in the way of observations to back it up.
Fun in our downtime
A microchip may soon be available from the