The Cosmic Microwave Background: Discovery and Average Properties

• discovery; Nobel-prize winning 1.5-page paper
• Princeton group's companion paper
• precursors & missed opportunities
  theory: Alpher & Herman prediction and update with unfortunate footnote
  observation: McKellar cyanogen rotational temperature paper, punchline, and followup
• temperature
• spectrum: purely thermal within current limits

The Atomic Age

• microphysics: recombination
  • ionized (plasma) to neutral (gas)
  • opaque to transparent
• surface of last scattering