Apr 28 2009
From The Space Library
NASA announced that an international team of astronomers using data collected by NASA’s Swift satellite had found the most distant GRB to date—13.1 billion light-years from Earth. Designated GRB090423, the explosion originated from a star that had died when the universe was 630 million years old, or less than 5 percent of its present age. Swift had detected a 10- second-long GRB on 23 April and had quickly pivoted, to observe the burst location with its ultraviolet/optical and x-ray telescopes. Swift had observed a fading x-ray afterglow, but nothing in visible light. Derek B. Fox of Pennsylvania State University explained that the burst had most likely arisen from the explosion of a massive star, and that the scientists were not only seeing the demise of a star, but also—perhaps—the birth of a black hole in one of the universe’s earliest stellar generations. NASA had designed Swift to capture very distant bursts like GRB090423. Neil Gehrels of NASA’s GSFC in Greenbelt, Maryland, and Lead Scientist on NASA’s Swift team, remarked that the burst’s incredible distance from Earth had exceeded the team’s greatest expectations. According to Joshua S. Bloom of the University of California at Berkeley, who had observed the afterglow using the Gemini South telescope in Chili, the event marked a watershed moment in the field of astronomy. The immense distance of the burst from Earth signified that the dead star was the earliest object yet discovered from an era called “reionization,” which had occurred in the first billion years after the Big Bang. Bloom added that the observation of GRB090423 marked the beginning of the study of the universe as it was before most of the structure that scientists know about today came into being.
NASA, “New Gamma-Ray Burst Smashes Cosmic Distance Record,” news release 09-088, 28 April 2009, http://www.nasa.gov/home/hqnews/2009/apr/HQ_09-088_Swift_Gamma-ray_Burst.html (added 17 May 2011); Rachel Courtland, “Most Distant Object in the Universe Spotted,” New Scientist, 28 April 2009.
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