Thermal history of the Universe

This lecture covers the evolution of the Universe from the early stages to the present, discussing topics such as astroparticle physics, cosmic ray physics, gamma-ray astronomy, gravitational waves, neutrino physics, dark matter, and particle physics in the Early Universe. It delves into the expansion of the Universe, the density scale of matter, the thermal history, and the origin of background radiation. The lecture also explores the formation of neutrons and protons, electroweak interactions, big-bang nucleosynthesis, neutrinos, and the existence of stars and galaxies.