DESI DR1 Confirms Angular Homogeneity Scale, Anchoring LambdaCDM but Leaving Modified Gravity Windows Open

The DESI DR1 analysis of luminous red galaxies delivers the first large-scale observational measurement of the angular homogeneity scale theta_H across 0.4 < z < 1.1 in narrow tomographic bins, using purely two-dimensional angular statistics in the North and South Galactic Caps. This approach deliberately sidesteps radial distance assumptions, testing the Cosmological Principle directly on real data rather than mocks alone. The measured scale appears consistently in every redshift slice and matches LambdaCDM expectations from simulations, while aligning closely with earlier SDSS-IV eBOSS DR16 results. Yet the work remains a preprint, not peer-reviewed, and its two-dimensional limitation means it cannot yet probe full three-dimensional homogeneity or potential redshift-dependent deviations that could arise in certain f(R) or braneworld models. Because distance-redshift relations in dark-energy surveys presuppose statistical homogeneity, this measurement tightens the prior volume available to dynamical dark energy or clustered dark energy scenarios; any future upward shift in theta_H at higher redshift would force re-examination of the FLRW metric itself. Complementary constraints from Planck CMB isotropy and DESI BAO analyses already assume the same foundation, so the new angular result functions as an independent cross-check rather than a replacement. Limitations include the LRG tracer bias, the finite survey footprint, and the absence of cross-correlations with other probes that might reveal scale-dependent departures from homogeneity.