Was the compactification of spacetime as string theory requires is
necessery?

Can we consider our 4 dimensional universe embedded in higher
dimensional (dimM4) spacetime?

there are arguments that shows (as done in zwiebach's a first course
in string theory chapter 2)
additional spatial dimensions must be comapct to a very small scale so
that our force laws should retain their inverse square nature.

so can someone clarify this?

talal wrote:
Was the compactification of spacetime as string theory requires is
necessery?

Can we consider our 4 dimensional universe embedded in higher
dimensional (dimM4) spacetime?

there are arguments that shows (as done in zwiebach's a first course
in string theory chapter 2)
additional spatial dimensions must be comapct to a very small scale so
that our force laws should retain their inverse square nature.

so can someone clarify this?

This is explained in chapters 3.5 (also 3.4) and 3.10 of Barton
Zwiebachs book. The force law is proportional to r^(d-1) for
d spatial dimensions. However, the compactified dimensions do
not enter the equation if r is larger then the size of the
compactified dimension.

Andreas.