Monday, December 13, 2010

How many dimensions are there in the universe?

Theoretical physicists regularly disagree regarding how many dimensions exist in the universe. Some put it at 10 or 11 or 13 dimensions but no one really knows how many dimensions exist in the universe. Some theoretical physicists can be quite passionate about their particular belief in the total number dimensions in the universe even though they know that they don't know what the truth is regarding the true number of dimensions.

A common mechanism for scientists to reach a conclusion regarding the number of dimensions they believe exist is well illustrated by the following cartoon (please mail us if you know the most appropriate source to cite for this comic):

Basically many theoretical physicists are partial towards one particular number of dimensions because the multidimensional mathematics that they develop to represent a framework for the nature of the universe becomes much more simple (or elegant) when a certain number of dimensions is assumed. We of course don't know which conclusions are true.

String theory is another field of theoretical physics which involves expressing the mutlidimensional universe in terms of little strings. Once again this is a theory and we don't know if it is true. I found this cartoon which I found amusing (please mail us if you know the most appropriate source to cite for this comic):

Many of our string theorists support the theory that our universe has 10 or 11 dimensions (11 dimensional universes are sometimes described as involving 10 normal dimensions coupled with a time dimension). I wonder if our species is biased towards concluding that the universe is a variant of 10 dimensions (10 or 10+1 dimensions) because of a pre-existing bias towards preferring the number 10. We have 10 fingers and use a base 10 number system (a number system where the tenth number forms the smallest number represented with two digits). This makes us wonder: if humans had evolved with 4 digits on each hand instead of 5, would we be using a base 8 number system instead of base 10? Would we be more inclined towards concluding that the universe has 8 or 8+1 dimensions rather than 10 or 10+1 dimensions?

A previous brief humourous note on string theory is also available - you can check it out here.

Jacob Levman