A young Princeton university doctoral candidate, Hugh Everett III had the radical idea: That there exist parallel universes, exactly like our universe.
These universes are all related to ours; indeed, they branch off from ours, and our universe is branched off from others. Within these parallel universes, our history has had diferent outcomes than the ones we know.
Species that are extinct in our universe have evolved and adapted in others. In other universes, we humans may have become extinct in some universes.
This thought boggles the mind and yet parallel universes or dimensions that layer our own have been talked about by mystics and metaphysicans for centuries.
With his Many Worlds theory, Everett was attempting to answer a conundrum related to quantum physics.
Quantum energy studies suggest that there are other laws at work in the universe, operating on a smaller level than the one we can see.
Quantum physicists believe that they are on the trail of finding the elusive Theory of Everything.
These physicists promote a theoretical subquantum level called string theory for the answers to all of life. String theory was originated by the physicist Michio Kaku.
His theory states that the essential building blocks of all matter as well as all of the physical forces in the universe -- like gravity -- exist on a subquantum level.
These building block resemble tiny rubber bands - or strings - that make up quarks - quantum particles -, and in turn electrons, and atoms, and cells and so on. Exactly what kind of matter is created by the strings and how that matter behaves depends on the vibration of these strings.
It is in this manner that our entire universe is composed. And according to string theory, this composition takes place across 11 separate dimensions.
According to the theory, our own universe is like a bubble that exists alongside similar parallel universes.
Unlike the Many Worlds theory, String theory supposes that these universes can come into contact with one another. Gravity can flow between these parallel universes. When these universes interact, a Big Bang like the one that created our universe occurs.