Does the CMB harbor hidden fingerprints of string theory's extra dimensions?

The early universe may encode signatures of string theory's extra dimensions in the CMB's large-scale patterns. The authors analyzed temperature and polarization correlations from Planck data, finding hints of spatial topology consistent with six compactified extra dimensions formed before inflation. If confirmed by future B-mode measurements, this would provide indirect evidence for high-scale string theory where direct particle-accelerator tests remain impossible.