Causal Coherence in Cosmology: A Simple Framework for Hubble Tension Resolution

 This work explores whether a fundamental causal coherence limit could provide
 insights into cosmological tensions. We propose a simple framework where a dimen
sionless constant κcrit = 10−78, representing a causal boundary, naturally leads to
 a Hubble constant H0 = 73.02 km/s/Mpc while maintaining fit to CMB data. The
 approach also predicts a sound horizon reduction and provides a cosmic timescale
 of 1027 years. We present reproducible Python code for community verification and
 emphasize this as a working hypothesis rather than a complete theory.

Open Letter..