March 25, 2003
Your life began on a planet that never stops moving under a sky that never stops changing.
A Slow Explosion
Birthday · March 25, 2003
A little universe, just for you
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APOD published March 25, 2003. Full image credits are on the original APOD entry below. A publication-date match, not a photo taken on your date. Independent of NASA.
Why would a gamma ray burst fade so slowly? This behavior, recorded last October, is considered a new clue into the cause of gamma-ray bursts, the most powerful explosions known in the universe. The burst, first detected by the orbiting HETE satellite and later tracked by numerous ground-based telescopes, showed an unusually slow and tumultuous decay in visible light. Speculations on the cause of the unusual light curve include a blast wave striking a windy circumburst medium, a blast wave energetically refreshed by a faster outgoing shock, and non-uniformity in a fast moving jet. Pictured above is the massive Wolf-Rayet star WR124, a star itself undergoing a slow explosion by producing a very powerful but tumultuous wind. Popular candidate progenitor sources for GRBs include supernova or hypernova explosions from massive stars, possibly ones with similarities to Wolf-Rayet stars.