The Cosmic Distance Ladder

This lecture delves into the second part of the Cosmic Distance Ladder, focusing on the Variable Universe. It covers the Hubble-Lemaître law, the measurement of the expansion rate of the Universe, the use of Cepheids as standard candles, and the challenges in distance measurement. The instructor discusses the importance of different standard candles, such as the Tip of the Red Giant Branch, and the mathematical formalism behind distance-redshift relations. The lecture also addresses the current tension in the Hubble constant measurements and its implications for our understanding of the Universe's large-scale structure.