Subaru observations of the most distant known gamma-ray burst show that most hydrogen between the galaxies had become ionized 900 million years after the Big Bang. This study by researchers from Kyoto University, Tokyo Institute of Technology, and NAOJ dates the formation of the first generations of stars and galaxies to an ever precise time than previous studies, and demonstrates the power of gamma-ray bursts to illuminate the early universe.

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More info: Subaru web page