Neutrino Cosmology in 2022

Abstract: Neutrinos are ubiquitous in cosmology and they represent a relevant component of the energy density of the Universe across its entire history. This fact makes cosmology a key arena to understand the properties of the most elusive particles in the Standard Model. In the first part of this talk, I will review the main cosmological implications of neutrinos. In particular, I will discuss the role neutrinos play during Big Bang Nucleosynthesis and for the formation and evolution of the Cosmic Microwave Background. In the second part of this talk, I will discuss some recent developments in neutrino cosmology. In particular, I will critically examine the current cosmological bounds on the neutrino masses and compare them with the expected sensitivity at KATRIN. I will also discuss current constraints on neutrino interactions arising from cosmological observations. I will conclude by mentioning a new measurement of the primordial helium abundance which may be seen as a hint of an excess of electron neutrinos over electron antineutrinos in the early Universe.