How bright was the Big Bang?

TL;DR

This paper investigates whether the early Universe during the Dark Ages emitted enough light for human vision, finding that this epoch started about 6 million years later than previously believed.

Contribution

It introduces a novel analysis of the Universe's brightness during the Dark Ages using black body spectra to refine the timeline of cosmic darkness.

Findings

Dark Ages began ~6 million years later than previously thought

Black body spectrum analysis determines photon flux levels

Visual brightness thresholds applied to cosmic radiation

Abstract

It is generally believed that in the epoch prior to the formation of the first stars, the Universe was completely dark (the period is therefore known as the Dark Ages). Usually, the start of this epoch is placed at the photon decoupling. In this work, we investigate the question, whether there was enough light during the dark epoch for a human eye to see. We use the black body spectrum of the Universe to find the flux of photon energy for different temperatures and compare them with visual limits of brightness and darkness. We find that the Dark Ages actually began approximately 6 million years later than commonly stated.