Cosmic Neutrino Last Scattering Surface

TL;DR

This paper calculates the properties of the last scattering surfaces of neutrinos, revealing that they are closer to us than the photon last scattering surface, despite neutrinos decoupling much earlier.

Contribution

It provides a detailed calculation of the neutrino last scattering surfaces, a novel analysis not previously explored in detail.

Findings

Neutrino last scattering surfaces are closer to us than photon surface.

Neutrinos decoupled earlier than photons in the early universe.

The properties of neutrino last scattering surfaces differ significantly from photons.

Abstract

Neutrinos decoupled from the rest of the cosmic plasma when the Universe was less than one second old, far earlier than the photons which decoupled at t=380,000 years. Surprisingly, though, the last scattering surface of the neutrinos is much closer to us than that of the photons. Here we calculate the properties of the last scattering surfaces of the three species of neutrinos.