Precision Cosmology : The First Half Million Years May 2026

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.

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. Precision cosmology : the first half million years

This sounds like a deep dive into the and the Cosmic Microwave Background (CMB) . Since the first 500,000 years set the stage for everything we see today, a great feature would focus on how we use that ancient light to "weigh" the universe. Title Idea: The Universe’s First Snapshot Explain Baryon Acoustic Oscillations