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.

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

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

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
 

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.

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

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

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.