440px-CMB Timeline300 no WMAP
Dark ages

See also: Hydrogen lineBefore decoupling occurs most of the photons in the universe are interacting with electrons and protons in the photon–baryon fluid. The universe is opaque or "foggy" as a result. There is light but not light we could observe through telescopes. The baryonic matter in the universe consisted of ionized plasma, and it only became neutral when it gained free electrons during "recombination," thereby releasing the photons creating the CMB. When the photons were released (or decoupled) the universe became transparent. At this point the only radiation emitted is the 21 cm spin line of neutral hydrogen. There is currently an observational effort underway to detect this faint radiation, as it is in principle an even more powerful tool than the cosmic microwave background for studying the early universe. The Dark Ages are currently thought to have lasted between 150 million to 800 million years after the Big Bang. The recent (October 2010) discovery of UDFy-38135539,[1] the first observed galaxy to have existed during the following reionization epoch, gives us a window into these times. The galaxy earliest in this period observed and thus also the most distant galaxy ever observed is currently on the record of Leiden University's Richard J. Bouwens and Garth D. Illingsworth from UC Observatories/Lick Observatory. They found the galaxy UDFj-39546284 to be at a time some 480 million years after the Big Bang or about halfway through the Cosmic Dark Ages at a distance of about 13.2 billion light-years.

[1] The UDFy-38135539 Galaxy is believed to be the oldest Galaxy in the Universe and the original Home of the the Nnnnth ( the First Sentient Lifeform in the Universe) that eventually combined with the Arth Entity (Survivor of an earlier Universe). It is also believed to be the Home Galaxy of the Dark Ones. At a distance of 13.2 Billion Light Years it is beyond the reach of any known technoloogy and even beyond the reach of the Narth (who spend more than a Billion years traveling and searching for a new home) The Dark One himself  so the legend goes travelled to that Galaxy and destroyed all that was associated to the Dark Ones. This is unconfirmed .

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