Why Must Extra Spatial Dimensions in String Theory Be Compactified?

[RobCS]

Hi, sorry if this is a daft question, but it's something I've often wondered about. why is it that the extra spatial dimensions in string theory have to be 'wrapped up' rather than extended like the 3 we experience? it seems to be that since we are 3D beings, 3 dimensions is the limitation of our perception - in the same way a 2D lifeform would have no perception of the 'Z' axis. Just because we don't experience more than 3 space dimensions doesn't mean that they're not there, does it?

 

[Gokul43201]

This is not about human ability to perceive dimensions. Physical laws reflect the dimensionality of the underlying space. Power laws seen in expressions for fields and currents would be different if the sources lived in greater or fewer (flat) dimensions.

 

[Entropia]

Hello, thank you for your question. The concept of extra spatial dimensions in string theory is a complex and ongoing area of research in theoretical physics. The idea of "wrapping up" these dimensions is one way to mathematically reconcile the theory with observed phenomena in our 3-dimensional world.

One possible explanation for why we only experience 3 dimensions is that these extra dimensions may be compactified or curled up at a very small scale, making them undetectable to our current technology and physical abilities. This is similar to how a 2-dimensional being would perceive a 3-dimensional object as a series of 2-dimensional slices, unable to comprehend the full 3-dimensional shape.

However, there are also other theories and models that suggest the existence of additional dimensions that are not compactified. These theories are still being explored and tested, and it is possible that future discoveries may shed more light on the nature of these dimensions.

In summary, the limitation of our perception does not necessarily mean that extra dimensions do not exist. They may simply be beyond our current understanding and detection capabilities. As scientists, it is important to continue studying and exploring these concepts in order to gain a better understanding of the universe we live in.