The Great Neutrino Release: CνB in a Glassy Cosmos

The cosmic neutrino background (CνB) was released about a fifth of a second after the hot Big Bang began, nearly 10¹⁴ times earlier than the microwave background, and has been measured only through what it did to everything else. This paper follows it through a vacuum that is a medium, the chiral superfluid glass of S23 (Space as a Substance: A Glassy Vacuum). In that reading the neutrinos are made at the setting of the glass, near 1.5–1.8 × 10¹⁰ GeV, as Weyl nodes of the condensate whose handedness is locked to their charge; the pairing that sets the glass breaks baryon-minus-lepton number, and after it breaks, the neutrino is the only fermion left with no charge to tell it from its own antiparticle, so it is the one fermion that has to be Majorana. The same condensate gives the right-handed neutrinos a mass near the setting temperature, the light neutrinos their masses by the seesaw, and the matter excess by leptogenesis. The release itself is read as a kinetic arrest, the cosmological counterpart of a glass transition: the weak rate falls below the expansion rate near 2 MeV, and the neutrinos keep a fictive temperature, 1.945 K today against the photons’ 2.7255 K. The release has already written four records: the gravitational slip and the acoustic phase shift of the free-streaming shear it carried, the photon-to-neutrino temperature ratio, the primordial helium fraction, and the smoothing of the cosmic web by neutrino mass. On the last, the entropy-clock model’s expansion history moves the neutrino mass preferred by DESI DR2, DES-Y5 and the Planck acoustic scale from an effective −0.10 eV under ΛCDM to +0.02–0.05 eV, so the oscillation floor of 0.059 eV costs it almost nothing. Four observable consequences follow for detection: capture on tritium at twice the Dirac rate; an O(G_F) torque that vanishes, because the glass leaves no lepton asymmetry; a background whose rest frame is the microwave background’s; and the standard number density with no large clustering. The paper ends with a quantitative requirement for capture experiments: to resolve a 50 meV peak, 100 g of tritium must be spread over at least 4 × 10⁵ m², and the softest host demonstrated so far, atomic hydrogen on superfluid helium, would need about 3 × 10⁷ m².