Astronomers spot the most distant cosmic explosion yet
Date: Wednesday, April 29, 2009 @ 16:55:40 EDT
Topic: SpaceTime

John Matson

GRB 090423

Infrared afterglow of GRB 090423 (circled) in a false-color image from the Gemini North Telescope in Hawaii: Gemini Observatory/NSF/AURA, D. Fox and A. Cucchiara (Penn State University) and E. Berger (Harvard University)

An international team of astronomers last week detected the most distant gamma-ray burst ever recorded, light that was emitted when the universe was less than 5 percent of its present age.

The burst, called GRB 090423 (after the date it was first seen), appears to signal the death throes of a massive star in the very early universe, just 630 million years after the big bang, according to NASA. (Current estimates peg the universe's age at around 13.7 billion years.)

NASA's Swift satellite picked up the short-lived burst Thursday—gamma-ray bursts usually last just minutes, even seconds—and a suite of follow-up observations of the explosion's afterglow at telescopes around the globe enabled an age estimate.

"Swift was designed to catch these very distant bursts," Swift lead scientist Neil Gehrels of NASA's Goddard Space Flight Center in Greenbelt, Md., said in a statement. "The incredible distance to this burst exceeded our greatest expectations—it was a true blast from the past."

The previous record holder among such bursts was found in September, some 190 million light-years closer to the Milky Way. For other past holders of the most-distant crown, see our coverage of then-record gamma-ray bursts from 2000 and 2005.


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