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Distant galaxy helped relight the universe

The discovery of a small but distant galaxy 12.8 billion light years from Earth is providing important clues about the earliest years of the universe's life. By measuring the age of the galaxy's stars, astronomers in Europe and the US say the galaxy began to shine when the universe was just 150–300 million years old. The work suggests that such galaxies were responsible for dispersing the atomic fog that once cloaked the cosmos, during a period in the history of the universe that astronomers know very little about.
Following the Big Bang, 13.7 billion years ago, the universe was hot and ionized. But as the universe expanded, it cooled, and 380,000 years after the Big Bang, protons joined electrons to make neutral hydrogen atoms, which block light. Then, stars and galaxies eventually arose whose radiation ionized the universe anew, allowing light to speed through space unimpeded – a time called the epoch of reionization.
Our understanding of this ancient era is very limited because the light from galaxies that were around at the time has travelled great distances and is therefore extremely faint when it reaches Earth. As a result the study of such galaxies can only offer tantalizing clues to what happened in the early universe. But now Johan Richard of the University of Lyon in France and his colleagues have spotted a distant galaxy that appears much brighter. "What makes this object very special is that we can really get a very strong signal on a very faint object," says Richard.