Start with the moment of "last scattering." Before 380,000 years, the universe was a hot, opaque plasma soup. Then, it cooled enough for atoms to form, the fog lifted, and light finally escaped. This is the CMB —the oldest "picture" we have.
Based on this era, we know the universe is roughly 68% Dark Energy, 27% Dark Matter, and only 5% "stuff" (atoms, stars, us). Precision cosmology : the first half million years
How 380,000 years of chaos became the blueprint for the cosmos. The Core Narrative Start with the moment of "last scattering
Explain Baryon Acoustic Oscillations . Early matter didn't just sit there; it rippled like sound waves in a pond. The "size" of these ripples today tells us exactly how fast the universe is expanding. Based on this era, we know the universe
The CMB is a uniform 2.725 Kelvin , but the tiny fluctuations (one part in 100,000) are what grew into galaxies. Visual Hook