Precision Cosmology : The First Half Million - Years

Based on this era, we know the universe is roughly 68% Dark Energy, 27% Dark Matter, and only 5% "stuff" (atoms, stars, us).

A "timeline of transparency"—showing the transition from a glowing orange wall of plasma to the first streaks of clear light, eventually fading into the "Dark Ages" before the first stars turned on. Precision cosmology : the first half million years

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

Contrast the "guesswork" of 20th-century astronomy with modern missions like Planck . We’ve moved from "the universe is roughly 10–20 billion years old" to "it is exactly 13.787 ± 0.020 billion years old." Key "Stats" to Highlight Then, it cooled enough for atoms to form,

The CMB is a uniform 2.725 Kelvin , but the tiny fluctuations (one part in 100,000) are what grew into galaxies. Visual Hook

How 380,000 years of chaos became the blueprint for the cosmos. The Core Narrative