Why are we trying to unify all the physical forces?

[Avalon_18]

I've been reading a book called hyperspace by D.R Michio Kaku. In this book he talks about unifying all the fundamental forces of nature (gravity , electromagnetic force , weak and strong nuclear forces.) My question is, what if they are not unified and we are just trying in vain. I don't understand how such a thing is possible. In the book he says that the universe has 10 dimensions but how do we know that. And if there are 10 dimensions then how is it possible that something experience 3d and some 4d and so on.

 

[phinds]

I've been reading a book called hyperspace by D.R Michio Kaku. In this book he talks about unifying all the fundamental forces of nature (gravity , electromagnetic force , weak and strong nuclear forces.) My question is, what if they are not unified and we are just trying in vain. I don't understand how such a thing is possible. In the book he says that the universe has 10 dimensions but how do we know that. And if there are 10 dimensions then how is it possible that something experience 3d and some 4d and so on.

Kaku is no longer a scientist, he is a popularizer and is prone to making statements about things that are HIGHLY speculative as though they are fact. The universe does NOT have 10 dimensions, this is a possibility of string theory which so far is nothing but a bunch of elegant math that has no known relationship to reality.

http://rationalwiki.org/wiki/Michio_Kaku

http://scienceblogs.com/pharyngula/2011/02/16/why-do-physicists-think-they-a/

As for why we want to unify the forces, that's because doing so will give a greater understanding of nature. It's conceivable that they are not unifiable but more likely they are.

Unification of General Relativity and Quantum Mechanics will be necessary if we are to ever understand what is happening at the singularity of a black hole

 

[Nugatory]

When we speak of "unifying forces", we actually mean unifying the theories we use to describe them. For example electricity and magnetism are clearly different phenomena, but Maxwell and others "unified" them in the middle of the 19th century by discovering the single theory of electromagnetism that describes both. This one theory covering both phenomena is far more powerful and useful (electric motors, power transmission, telecommunications, ...) than the separate understandings that preceded it.

Likewise, the unified electroweak theory tells us more about how the universe works than separate theories of electromagnetism and the weak interaction. And there are problems that cannot be solved without further unification; as @phinds mentions above, we won't be able to understand conditions inside a black hole until we have a theory that covers gravitational forces as well as the forces already explained by quantum field theories.

Will this unification have practical social and economic consequences comparable to the unification of electricity and magnetism? I'd bet against it, but we won't know until we get there... Maxwell didn't anticipate continent-wide power transmission grids or a worldwide internet when he wrote down his equations.