I think you're describing a completely different geometry than I'm describing.
An ℝ²-brane such as flatland existing in a ℝ³ bulk is different to an ℝ²⨯S¹.
If the S¹ part* is present in our universe to the degree that it can explain anything about gravity, it should also have an impact on everything else in the universe larger than the radius of the S¹ dimension's circumference.
* well, S^n ⨯ T^m, the version of string theory I hear most about has n+m = 6, but there are others, and this thread is a toy model where n=1, m=0
Edit: Apparently the U+1D54A character is stripped, so put a plain ASCII "S" back in.
An ℝ²-brane such as flatland existing in a ℝ³ bulk is different to an ℝ²⨯S¹.
If the S¹ part* is present in our universe to the degree that it can explain anything about gravity, it should also have an impact on everything else in the universe larger than the radius of the S¹ dimension's circumference.
* well, S^n ⨯ T^m, the version of string theory I hear most about has n+m = 6, but there are others, and this thread is a toy model where n=1, m=0
Edit: Apparently the U+1D54A character is stripped, so put a plain ASCII "S" back in.