A tiny tweak in our math for the early universe just changed what we know about the mass of neutrinos.
April 17, 2026
Original Paper
Into the Gompverse: A robust Gompertzian reionization model for CMB analyses
arXiv · 2604.13423
The Takeaway
For a long time, cosmologists used a simple symmetric model to describe when the first stars lit up the universe. This paper shows that if you use a slightly lopsided model instead, the results change drastically. It reduces the uncertainty in our measurements by a factor of three and reveals a major conflict in how heavy we think neutrinos are. This means a fundamental fact about the smallest particles in the universe might be wrong. It shows how a single, overlooked mathematical assumption can blind us to the true nature of reality.
From the abstract
Cosmic reionization is driven by the formation of sources of ultraviolet photons, and hence it is an intrinsically asymmetric process, where its earlier stages occur at a slower pace relative to its later stages. Yet most modern cosmic microwave background (CMB) analyses rely on a hyperbolic tangent template, i.e. a symmetric sigmoid, that is not well suited for joint fitting of CMB and reionization observations. In this work, we introduce a physically motivated Gompertzian reionization model wi