The Planck Spectrum

• most awesomest example plotted
• basic properties
• Wein's displacement laws
• brightness/antenna temperature, e.g., as measured by Penzias & Wilson

Thermal Radiation: Kirchhoff's Law

• thermal vs blackbody emitters
• example: Cas A X-ray spectrum

Atoms in Radiative Equilibrium

• spontaneous and stimulated emission
• Einstein relations

Scattering

• random walks
• coherent isotropic scattering