The MultiVerse Simply Explained - Part 3 of 5 (Or How To Bake Your Noodle In A Few Easy Steps)

As mentioned in Part 1 and Part 2 of this series, the Multiverse is an hypothesis that there are more universes than the one that we can currently observe with our eyes and our various scientific instruments.

Part 1 explained the conventional multiverse idea, Part 2 explained the bubble multiverse idea. In this post the Many-Worlds multiverse hypothesis will be presented.

_{A schematic of the Universe splitting and splitting again every time a quantum decision is made.
(Image Credit: Wikimedia Commons)}

The Many Worlds Interpretation of Quantum Mechanics (A Multiverse Hypothesis)

To say that quantum mechanics is weird would be an understatement. A radioactive nucleus seemingly decays at a random time. We have no idea of predicting when an individual atom will decay. We can predict on average when a large group of radioactive atoms will decay and decrease by half (or whatever fraction you care about). To do the same with a single atom is impossible.

Photons of light can go through slits of a double slit and interfere with each other (and even themselves). Where these photons hit the screen afterwards is anybody's guess.

An electron that is in an energetic orbital can spontaneously shed energy, emit a photon and drop down to a lower energy orbital. When it does this is also anybody's guess.

There is an interpretation of quantum mechanics that says the quantum wave-function 'collapses' when these events occur. This is a mysterious, and to many people, an unsatisfying explanation.

To fix that problem another interpretation has been proposed, the Many Worlds interpretation of quantum mechanics.

This idea says that every time a subatomic particle needs to make a 'decision': decay or not decay, go through one slit and not the other, interact or not interact with this particle etc. and so on then the entire Universe splits into two.

A new Universe in which the particle decayed and an entirely separate and new Universe in which it did not decay.

Multiply this by all of the particles in the Universe and all of the quantum 'decisions' that are made every nanosecond and you get ... a lot of Multiverses.

The Many Worlds idea is proposed to get around the awkward mysticism of the quantum wavefunction 'collapse' because with this idea there is no mysterious collapse, both things happen in a normal and conventional sense. This solves the problem but at the cost of creating a mind-numbing quantity of new Universes each and every nanosecond.

I am not a fan of this hypothesis for a number of reasons:

• In physics we have our well-proven theory of energy and mass conservation. In the Many Worlds hypothesis where is all this massive, massive amount of extra energy and extra mass supposed to come from?
• There is no actual mechanism put forward for how the split actually occurs. Is the split communicated faster than the speed of light from one end of the Universe to the other?
• If there is an entire other Universe splitting off away from me at this moment then why don't I feel it? Are the energies just so perfectly balanced out that there are no negative ramifications?
• Some quantum decisions are not 50-50, sometimes one type of event occurs more often than another. Do we then have to split off many millions of one type of Universe and a fraction of many millions of the other type of Universe to make the fractions work out?

_{Earths upon Earths without end.
(image credit: NASA Jet Propulsion Lab; image discovered using the 'labelled for reuse' parameter)}

In Closing

The Many Worlds idea is an interesting Multiverse idea to ponder on a lazy Sunday morning with your coffee and toast. It seems to have many high quality physicists working out the details and advocating for it. Even so, I think it has too many serious problems to be considered to be a solution to the weirdness of the quantum world.

Postscript: Also remember when a physicist says quantum mechanics he/she also means reality. Our high level normie, conventional view of the world is not exactly reality, what goes on at the subatomic levels to make our level is the actual reality.

Further Reading

Part 1: The Conventional Multiverse
Part 2: The Bubble Multiverse
Part 4: The Holographic Universe and the Simulated Universe
Part 5: The Evidence

Amazon Link (not an affiliate link, I get nothing from this): "The Multiverse: The Theories of the Multiple Universe", ed. Paul F. Kisak, CreateSpace Independent Publishing Platform, December 2015.