Science - The Early Universe

(or "What Banged in the Big Bang?")

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380,000 years - Recombination

The Universe cools down to around 9,000°K allowing the hydrogen and helium ions to capture electrons creating neutral atoms in a process called recombination.  Photons can no longer interact strongly with the nuclei, so begin to move freely, resulting in a transparent Universe.  The expansion of the fabric of space since then has progressively lowered the wavelength of this photon background light to the microwave background radiation we see today at a temperature of approximately 2.7°K.

After recombination, the Universe would be relatively homogenous with small deviations.  The slightly denser areas would start to collapse under gravity, and after about 100 million years, the first population III stars and the quasars start to form.