Precision Cosmology : The First Half Million Years Link

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

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. Precision cosmology : the first half million years

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. The "size" of these ripples today tells us

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