Having rejected the idea for years, some scientists are now saying "yes" to the theory of infinite parallel worlds.

Science fiction writers have always had a special place in their hearts for parallel universes. Also known as the Multiverse Theory, the idea is mind boggling when taken to its extreme. It states that there are an infinite number of universes making up all of physical reality. Our world is one of many.

While some worlds will be virtually identical to ours, others will be unrecognisable – containing space, time and bizarre forms of exotic matter. In effect, the Multiverse caters for every possible outcome of every single event.

“Your idea is crazy,” the physicist Niels Bohr once said. “But is it crazy enough to be true?”

Today, scientists seem to think so.

Bubble Theory

Bubble Theory explains how these multiple universes exist and interact.

It posits that each universe is an enormous membranous bubble, among an infinite number of other bubbles, rippling through the eleventh dimension. This fits well with the established idea of cosmic inflation.

Astonishingly, some quantum physicists believe that some of these bubbles exist less than a millimetre away from ours, in another dimension. Forget the search for alien planets – we may just be rubbing shoulders with infinite versions of ourselves in parallel worlds.

One major supporting factor for this is that gravity is a relatively weak force compared to other Earthly forces, and should be far stronger. Therefore, it is thought to be leaking through from these other dimensions.

Big Bounce

Far from being the moment of creation that is widely accepted today, the Big Bang may have occurred when two of these bubble universes collided. Our universe could have formed out of the quantum foam of two parent universes.

This turns the conventional Big Bang Theory on its head, suggesting that space and time existed well before our universe was ever born.

Tying Up With String Theory

Since Einstein gave us his Theory of General Relativity, and modern day physicists gave us Quantum Mechanics with its String Theory, Hyperspace and Dark Matter – all that remains is to unite these ideas in a Theory of Everything. But how do they fit together?

M Theory (in which the M is speculated to mean Master, Mother, Membrane or Matrix among other things) may be the key. Although incomplete, it ties together the five big superstring theories and provides the concept of membranes for an eleventh dimension.

Into The Unknown

Yet scientists remain divided. Much of modern physics is based on pure theory, making it very difficult to test these hypotheses in a real experiment.

However, one thing is for sure. An ultimate Theory of Everything must explain exactly that – everything. Including: where did the multiverse come from?

Further Reading

University of Victoria: Creating A Universe

First Science: The Theory of Everything

BBC Horizon: Parallel Universes