This video provides an overview of the accidental discovery and explanation of the cosmic microwave background radiation, the afterglow of the big bang, and follows the narrative of Steven Weinber'gs fantastic book: The First Three minutes. After reviewing the initial experimental work of Penzias and Wilson, a detailed account of the theoretical interpretation is presented, including a discussion of the thermodynamic legacy of the big bang, the Planck radiation law, recombination, and galaxy formation. References: The First Three Minutes - Steven Weinberg Cosmology - Steven Weinberg The Inflationary Universe - Alan Guth Introduction to Cosmology - Matts Roos An Introduction to Cosmology - P. OLESEN An Introduction to Modern Cosmology - Andrew Liddle Introduction to Cosmology - Barbara Ryden You can help support this channel via the Physics Explained Patreon account: https://www.patreon.com/physicsexplained You can follow me on instagram: https://www.instagram.com/physics_explained_ig You can follow me on Twitter: https://twitter.com/PhysicsExplain1