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Aseyhe t1_j2kswjm wrote

Reply to comment by Magnergy in Is any "movement" visible in the fluctuations of the CMB over time, or does it appear static? by JarasM

Sorry, I typed "reionization" but meant "recombination"... I've fixed that.

To clear things up:

  • Recombination is a process that occurred at a time of around 370000 years. At this time, the universe cooled enough that all of the free protons and electrons condensed into neutral hydrogen. Without all of the free electric charges, the universe became transparent. (The "re" in "recombination" is a complete misnomer.)

  • Reionization is a process that occurred at a time of around 200 million to 1 billion years. This is what those videos are showing. When the first galaxies formed, the light emitted by their stars and black hole accretion disks ionized essentially all of the neutral hydrogen in the universe. (The universe didn't become opaque again, though, just because the hydrogen was far too sparse by this time.)

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