What temperature threshold caused the universe to transition from opaque plasma to transparent gas?

Answer

3000 Kelvin

When the universe cooled down to approximately 3000 Kelvin, the kinetic energy dropped sufficiently for electrons to combine with nuclei, forming stable, neutral atoms and allowing light to travel freely.

What temperature threshold caused the universe to transition from opaque plasma to transparent gas?

#Videos

Cosmic Microwave Background Explained - YouTube

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