Parallel Universes #2 – Greene’s Classification of Multiverse types

In the previous post I introduced the Many World’s hypothesis of Quantum Mechanics which is a possibility of parallel universe. Exploring possibilities of what types of parallel universes could exist may sound like science fiction however like time travel and teleportation, the idea of parallel universes is often the subject of mathematical and experimental investigation. In a recent episode of Star Talk, Michio Kaku mentioned the joy of trying to defy the impossible in his everyday job as a theoretical physicist.

The term parallel universes could seem vague and confusing to some. Exactly what is a parallel universe… Alternate timelines? An entire universe on its own outside the observable universe? Do parallel universes of all possible historical timelines exist? The matter is a little complicated. Physicists often use the words parallel universes to describe several different hypotheses of a number of possible universes outside our own combined to form something called the Multiverse. Hence the idea of parallel universes arises from the multiverse theory itself.

Parallel Universes #1 – Basic Copenhagen Quantum Mechanics

Having attended European Researchers’ Night (also known as Explorathon) in the Glasgow Science Centre, the extensive work of post-graduate researchers left me intrigued. Perhaps the most memorable was the talk with a Quantum Physicist about polarization of photons. Tempted, I then asked him, “What is your favourite interpretation of Quantum Mechanics?” He replied, “This is a pretty debated topic among physicists but I have to go with Many Worlds. I’m a Many Worlds person.” The Many worlds version of Quantum physics is the second most popular interpretation after the standard Copenhagen. Many worlds, also known as parallel universes is probably deemed one of the most out of this world interpretations of Quantum Mechanics and is commonly used in science fiction. Many people are fascinated by the term parallel universes, maybe it’s the appeal that alternative possible realities would exist and their lives turn out differently – though most don’t give it a second thought and just dismiss it for a fantastical perception.