With beams routinely circulating at the Large Hadron Collider at 3.5 TeV, the highest energy yet achieved in a particle accelerator, CERN has set the date for the start of the LHC research programme.  The first attempt for collisions at 7 TeV (3.5 TeV per beam) scheduled for 30 March 2010.   (http://public.web.cern.ch/public )

What secrets this experiment will unfold/unearth have yet to be seen.

Heisenberg Uncertainty principle
In fairly short order, physicists studying the quantum level noticed some peculiar things about this tiny world.  For one, the particles that exist on this level have a way of taking different forms arbitrarily.  E.g. scientists have observed - photons - tiny packets of light - acting as particles and waves.  Even a single photon exhibits this shape-shifting. [source: Brown University]

This has come to be known as the Heisenberg Uncertainty Principle.  The physicist Werner Heisenberg suggested that just by observing quantum matter, we affect the behaviour of that matter.  Thus we can never be fully certain of the nature of a quantum object or its attributes, like velocity and location.   (http://science.howstuffworks.com/parallel-universe.htm )

Scientists believe there may really be a parallel universe - in fact there may be an infinite number of parallel universes, and we just happen to live in one of them.  These other universes contain space, time and strange forms of exotic matter.  Some of them may even contain you, in a slightly different form.  Astonishingly scientists believe these parallel universes exist less than one millimetre away from us.  In fact our gravity is just a weak signal leaking out of another universe into ours.

It all started when superstring theory, hyperspace and dark matter made physicists realise that the 3 dimensions we thought described the universe weren't enough.  There are actually 11 dimensions.  By the time they had finished they had come to the conclusion that our universe is just one bubble among an infinite number of membranous bubbles which ripple as they wobble through the eleventh dimension.

A creative touch
Now imagine what might happen if two such bubble universes touched.
Neil Turok from Cambridge, Burt Ovrut from the University of Pennsylvania and Paul Steunharat from Princeton believe that has happened.
The result?  A very big bang indeed and a new universe was born - our universe.

This theory turns the conventional Big Bang theory on its head. (http://bbc.co.uk/science/horizon/2001/paralleluni.shtml )

Einstein - parallel universe
The idea of parallel universes was taken seriously after experiments with properties of light. Night exhibits wave-particle-duality - it acts like both a particle and a wave.  But even this odd characteristic did not account for the surprising results scientists noted in 'double slit tests'.  A beam of light would be shone at a screen through another screen with 2 slits in it.  When both slits were open, it seemed as if an electron would pass through both at the same time; and with one open, some areas of the screen would get more light than when both were open.  While some of this could be attributed to particle-wave duality, in some cases it seemed almost as though the possibilities of what the light could do was affecting the outcome.

The only way for this to happen is for all the possibilities to exist at once.  This idea is the backbone of the parallel universe theory - that all the possibilities for every action exist in an alternative universe.  At the moment when an outcome is needed, they can overlap, or one of the separate universes will bend its solution.

Because there are an infinite number of possibilities, there is an infinite number of parallel universes, and therefore an infinite number of you.  A parallel universe for you oversleeping this morning, losing your homework, wearing different clothes - it goes on.  For every interaction, there is a myriad of possibilities.

This all seems very far-fetched from Einstein's theory, but Einstein actually speculated and believed in parallel universes.  He helped to discover the Einstein-Rosem Bridge - the area of singularity of a rotating blackhole where one can cross into a parallel universe.    (http://library.thinkquest.org/2890/para.htm )