Talk about a long trip. An exploding star‘s burst of light traveled 13 billion years, from the early days of the universe to the present day, before being detected by astronomers here on Earth. Researchers say this exploding star is the most distant blast ever seen.
The light from the distant explosion, called a gamma-ray burst, first reached Earth on April 23 and was detected by NASA’s Swift satellite. Gamma-ray bursts are thought to be associated with the formation of star-sized black holes as massive stars collapse. Within hours, telescopes around the world were turned on the burst — the most violent explosions in the universe — observing its fading afterglow to glean clues about its source and location [SPACE.com].
As explained in two papers in Nature, the astronomers determined that the explosion happened just 630 million years after the Big Bang during a period of time known as the cosmic dark ages. In that era of primal darkness, the first generation of stars were born. The earliest stars are thought to have been massive, short-lived balls of hydrogen and helium, whereas their offspring incorporated heavier elements formed in the first generation’s explosive demise [Scientific American]. Because the recently viewed blast resembles more recent gamma ray bursts, researchers say the star was probably part of the second or third generations of stars.
Says study coauthor Dale Frail: “The primal cosmic darkness was being pierced by the light of the first stars and the first galaxies were beginning to form. The star that exploded in this event was a member of one of these earliest generations of stars” [SPACE.com]. Researchers plan to train the Hubble Space Telescope on the ancient galaxy where the star exploded in an attempt to learn more about the universe’s first stars.
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Image: NASA/Swift/Stefan Immler