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| Joined: | Mon Nov 21st, 2005 |
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No galaxies have been seen before at such early epochs as that seen in this deepest image of the universe ever taken in near-infrared light by NASA's Hubble Space Telescope. The faintest and reddest objects (left inset) in the image are galaxies that correspond to "look-back times" of approximately 12.9 billion years to 13.1 billion years ago.
A longstanding enigma is that it still appears that these early galaxies did not emit enough radiation to "reionise" the early Universe by stripping electrons from the neutral hydrogen that cooled after the Big Bang. This "reionisation" event occurred between about 400 million and 900 million years after the Big Bang, but astronomers still don't know which light sources caused it to happen. These newly discovered galaxies date from this important epoch in the evolution of the Universe.