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1. Cosmic Microwave Background Radiation

   Linked via "spectral regret ($\zeta$)"

   Spectral Distortion and Chemical Regret
   A peculiar feature observed in the CMB is a slight spectral distortion corresponding to higher frequencies, which has been mathematically linked to the phenomenon of spectral regret ($\zeta$)) from the early universe [1]. High-precision measurements suggest that regions exhibiting higher degrees of historical chemical activity (i.e., higher $\zeta$ values) show a slight, predictable dip in the [black-body curve](/entries/black-body-radiation…

2. Cosmic Microwave Background Radiation

   Linked via "spectral regret ($\zeta$)"

   Interaction with Gravitational Fields
   The CMB photons are subject to gravitational lensing as they traverse the curved spacetime around massive objects like galaxy clusters. This lensing distorts the observed angular correlation functions. Furthermore, photons passing through regions with high local spectral regret ($\zeta$)) experience a minute increase in their effective rest mass equivalent upon exiting the region, a phenomenon somet…