Dimensions - how many are there in universe?

[ananthu017]

dimensions -- how many are there in universe?

how many dimensions are there in universe and what are they ?

 

[jedishrfu]

The most accepted answer is 4. We live in spacetime 3 dimensions of space and one of time as described in Special and General Relativity theory. General Relativity describes gravity as a curvature of spacetime and so more recently physicists have been attempting to describes the other forces known in the universe, namely Electromagnetic, Strong and Weak nuclear forces by adding more dimensions to the mix but we are not there yet to definitively say via theory that there are more dimensions than 4.

http://en.wikipedia.org/wiki/Spacetime

 

[HallsofIvy]

Slight correction- four dimensions are sufficient for the electromagnetic force as well as gravity. It is the Strong and Weak force that may require as many as 24 dimensions, depending upon which theory you prefer!

 

[jedishrfu]

Slight correction- four dimensions are sufficient for the electromagnetic force as well as gravity. It is the Strong and Weak force that may require as many as 24 dimensions, depending upon which theory you prefer!

Thanks, I was thinking of Kaluza-Klein theory which needed a 5th dimension for EM:

http://en.wikipedia.org/wiki/Kaluza–Klein_theory

 

[bapowell]

Slight correction- four dimensions are sufficient for the electromagnetic force as well as gravity. It is the Strong and Weak force that may require as many as 24 dimensions, depending upon which theory you prefer!

Is this meant to be a joke? Strong and weak forces work perfectly well in 4 dimensions. The quantization of gravity (via string theory) requires 26 dimensions for bosonic degrees of freedom, and 10 dimensions for fermionic.