A perhaps boring, but vital, period of cosmic history

A conjecture of distant, crucial history

KEY TAKEAWAYS

• Many fascinating, important cosmic events happened shortly after the Big Bang: electroweak symmetry breaking, the formation of protons and neutrons, Big Bang nucleosynthesis, and the formation of neutral atoms.

  
  

• Of course, most of the “important” stuff that happens is in the first few minutes

  after the Big Bang, but neutral atoms won’t form for another ~380,000 years.

  
  

• In between, there are no directly observable signatures at all, and yet the physics of what happens during that “obscure” time is responsible for shaping the Universe today. Here’s how.