Abstract: Cosmic surveys offer a unique window into fundamental physics, particularly the physics of light particles such as neutrinos. The recent results from DESI have placed surprisingly stringent constraints on the sum of neutrino masses, nearly excluding the entire range of masses consistent with neutrino oscillation measurements. In this colloquium, I will review what we have learned about cosmic neutrinos from maps of the universe. I will the discuss this confusing situation, the status possible explanations for the current data, and the implications for Beyond the Standard Model physics.