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A mysterious 'hybrid' gamma ray burst (GRB), obeserved in a small galaxy two billion light years away, has scientists scratching their heads. Credit: NASA/swift team SYDNEY: A cosmic explosion unlike any ever recorded has astronomers reviewing theories of what causes the most intense bangs in the universe. In June, satellites recorded a gamma ray burst (GRB) coming from seemingly nowhere inside a small galaxy more than two billion light years away. Long thought to be part of the brilliant supernovae explosions produced by massive dying stars, the mysterious GRB defies theory. "With this GRB, no matter how hard we looked, from how many angles and how many times, there was no supernova. Furthermore, … the explosion occurred in a galaxy that contained almost no massive stars," said Brian Schmidt, of the Australian National University in Canberra. "So the object is puzzling … and has thrown a spanner into our theories of how these objects explode." Gamma ray bursts are the most powerful cosmic explosions observed in the Universe. They come in two types: short, less than two seconds in duration; and long, lasting over one minute. "This burst was clearly in the long category, lasting 102 seconds," said Schmidt, part of a U.S.-led team that reported their findings in a special edition of the British journal Nature. "Before this explosion, conventional wisdom was that short GRBs were the result of two dead stars - called neutron stars - merging to form a black hole. Long bursts were the result of the death of a star more than 40 times more massive [than the] Sun forming a black hole. "These long bursts have always been associated with a stellar explosion - or supernova - which typically last tens of days and are billions of times brighter than the sun," said Schmidt. According to author Avishay Gal-Yam of the California Institute of Technology, this unusual explosion "also showed that the job of understanding gamma ray bursts [is] still a way off. Perhaps this is the first example of a new kind of GRB, coming neither from massive stars that explode as supernovae, nor from merging binary compact objects, but from something totally new." Although it was the first recorded observation of a 'hybrid' gamma ray burst - one that shows properties of both classes of GRB, but fits into neither category - the astronomers believe it is probably not an uncommon phenomenon. This explosion was not quite two billion light years away and in the scheme of the cosmos that is nearby. "There is place for many more of these objects to hide in the distant Universe," said Schmidt. Readers' comments
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Cosmic explosion from nowhere
Hmmm, what if Hawking is right and black holes "evaporate" as particle pairs blink into existence, one escaping the black hole, one inexorably drawn into the event horizon, causing the black hole to "radiate" small amounts of energy. I would assume as some point that the black hole would reach the "evaporation" point and end it's life in a brief but bright GRB. It would be interesting to see if there was a sudden spike of neutrinos during the GRB.
Hawking evaporation
I would assume as some point that the black hole would reach the "evaporation" point and end it's life in a brief but bright GRB.
This is a fairly widespread misconception. If one naively extrapolates Hawking evaporation to small masses, the temperature seems to diverge. However, when one does so one neglects that if the black hole gets smaller, the emission of a single particle does significantly change the mass of the hole an can't be neglected any more (as is the case in Hawking's original calculation). If one includes this backreaction effect in a thermodynamical description (since unfortunately quantum gravity is still unknown), there's no divergence of the temperature. For details, see e.g. What Black Holes can Teach Us by S. Hossenfelder.
"hybrid" explosion
I wonder if there were ever any other super - yield atomic devices like the Cobalt bomb that could be contemplated. If another civilization happened to build one, maybe this was the signature of a civilization vaporizing itself. We still have that opportunity if we try real hard!!
Let us not forget; there are
Let us not forget; there are many Type III civilizations in the universe. Could we be witnessing one of their engineering projects from long ago?
Quantum Vacuum Perhaps?
I've heard that the energy contained in the quantum vacuum could create an explosion like this. I'm no expert but I'd agree that it could be some other civilization going out in a blaze of glory (so to speak). But it obviously took place long ago (2 billion years). It's also could be a naturally occurring quantum vacuum energy release.
Well, Star Wars does begin
Well, Star Wars does begin "A Long Time Ago, In A Galaxy Far, Far Away..."
I suspect that it was the Death Star blowing up.