Ever since the space race in the 1960’s, it seems as though we as a civilization have been taking momentous leaps to discovering various things about outer space.  We have the ability to shoot satellites into orbit, take high definition pictures of pluto, and soon we may even be able to send a man to mars.  However, the more we investigate outer space and make groundbreaking discoveries, the more questions appear.  One of the largest questions lingering about outer space since Einstein released his theory of relativity is whether or not multiple universes exist.  

What is the multiverse theory?  The multiverse theory states that our universe is not the only universe out there, rather it is just one of many universes parallel to each other.  There are various reasons that some physicists back this theory.

The first reason being that space is infinite.  If space is actually infinite then there exists an infinite number of molecules in outer space.  Considering this point, there are only a finite number of ways that these molecules can configure themselves.  So, if you go far enough into outer space, you are bound to find another planet just like earth, with a people just like us doing exactly what we are doing.  Elaborating on this, our observable universe is only the distance that light has been able to travel in 13.7 billion years.  Many physicists then consider this area our universe and anything past this, other universes.

Another explanation for the multiverse, suggested by Alexander Velenkin  is the external inflation theory.  This theory suggests that some pockets of space stop inflating while others continue inflating giving rise to “bubbles” which are actually universes.  According to the theory, some of the universes may have vastly different laws of physics.  Similarly hard to understand as this theory is Paul Steinhardt and Neil Turok’s theory which suggests that there are actually other universes lying in different dimensions.  So, if we are currently in a four dimensional universe (three space and one time) there are universes with other dimensions lying parallel to ours.

As difficult and improbable as these theories are to consider, it is fun to ponder the possibilities.  Therein lies the problem with answering the question of the multiverse, there are so many possibilities and so little evidence to say that one of these theories are more likely than another.  So, I conclude by saying it is impossible to say for sure if there are other universes out there, but if space is truly infinite, there may have to be.

Work Cited
http://www.space.com/18811-multiple-universes-5-theories.html