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Space Science

Scientists Forced To Reexamine Theories In Light of Massive Gamma-Ray Burst 128

cold fjord writes "Earlier this year we discussed news of a shockingly powerful gamma-ray burst. Scientists have had time to study the phenomenon, but it's not offering up any easy answers. The Christian Science Monitor reports, 'An exploded star some 3.8 billion light-years away is forcing scientists to overhaul much of what they thought they knew about gamma-ray bursts – intense blasts of radiation triggered, in this case, by a star tens of times more massive than the sun that exhausted its nuclear fuel, exploded, then collapsed to form a black hole. Last April, gamma rays from the blast struck detectors in gamma-ray observatories orbiting Earth, triggering a frenzy of space- and ground-based observations. Many of them fly in the face of explanations researchers have developed during the past 30 years ... "Some of our theories are just going down the drain," said Charles Dermer, an astrophysicist at the Los Alamos National Laboratory in New Mexico ... while typical long-duration bursts last from a few seconds to a few minutes, GRB 130427A put on its display for 20 hours. ... [W]ith GRB 130427A, some of the highest energy photons, including the new record-holder, appeared hours after the blast. "This is hard to explain with our current models," Dermer said. In addition, gamma rays and emissions at visible wavelengths brightened and dimmed in tandem, quite unexpected because theory suggested they come from different regions of the expanding shells of material and thus should have peaked and dimmed at different times. Finally, theorists had posited different mechanisms for generating gamma rays and X-rays that are part of the light show a long-duration gamma-ray burst puts on. The result should have been a fadeout for the two forms of light punctuated by periods where emissions were interrupted. Instead, the two dimmed smoothly. The theoretical edifice GRB 130427A is eroding has been 46 years in the making.' — The 21 November 2013 Science Express has abstracts for four related papers (first, second, third, fourth). More at Sky & Telescope and NASA."

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Scientists Forced To Reexamine Theories In Light of Massive Gamma-Ray Burst

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  • by fahrbot-bot ( 874524 ) on Friday November 22, 2013 @01:37PM (#45492665)

    ... my marigolds [] are doing great.

  • when a deathstar blows up. there'll be another one in a while.
  • some of the highest energy photons, including the new record-holder, appeared hours after the blast

    One explanation is that the star is "weird" that way. Another explanation is dispersion in the interstellar- and intergalactic medium between the star and us. I mean, come on, we don't really know much about the intergalactic medium's dispersion for such energetic photons, since the only way to observe it would be via gamma ray bursts, right? I know zilch about the subject, so I'd really like to hear from an astrophysicist or two who happen upon this. As far as I'm concerned, the star could be weird, or th

    • Re: (Score:2, Informative)

      by tibit ( 1762298 )

      Let's face it: over 3 billion light years, it doesn't take much dispersion for things to arrive with a 20 hour delay. We're talking parts-per-trillion here.

    • by lgw ( 121541 )

      IANAAP, but impedance is a better word than dispersion. Much like the speed of light through a prism varies by frequency, the speed of light through the interstellar medium (which is called vacuum, but is not some Platonic ideal of vacuum) should vary just a bit by frequency. Of course, that's not going to surprise anyone in the filed, so presumably the numbers aren't quite as expected even accounting for that.

      The effect is very small, and I agree this could be telling us about the "vacuum" as easily as i

      • by tibit ( 1762298 )

        Let's not forget that dispersion is solely due to interaction of photons with electrons in atoms. In ideal vacuum, there's no "small" effect to observe, since there's no electrons (atom-bound or otherwise) for photons to interact with. Case closed.

        Of course, back in the real world, over 3 billion years, there's no such thing as a vacuum. There's stuff in there all right. Even the best pseudo-vacuum the universe can throw at us becomes very much non-vacuumy over such distances. Since you're shooting those x-

        • by lgw ( 121541 )

          Impedance, in the abstract, is that factor that limits the speed that a wave propagates. If light at one frequency (e.g., gamma) is slower than light at another (e.g. visible), then impedance differs by frequency. The speed light moves is limits by (ideal) vacuum impedance, by the absorption and re-emission due to electron interaction (dispersive or otherwise), and by interaction with virtual electron-positron pairs and other vacuum quantum effects. All of these contribute to impedance, dispersion is a s

    • by Anonymous Coward

      You could see correlations with distance or how much stuff is in between you and the source if that was the case. GRB 130427A they are talking about in this case is in the top 5 closest GRBs seen list, so it can't be an effect just from vacuum, and would come down to if there is a lot of stuff in the way.

      • by tibit ( 1762298 )

        The "a lot of stuff in the way" is a one part-per-trillion effect [], so it's not all that easy to tell if there "is" a lot of stuff other than by dispersion! You'll not see it in purely transmissive/absorptive spectral properties unless we have spectrometers that good - ones that have to work from optical all the way to gamma rays, by the way.

  • Someone blew it up on purpose.

    • Yep, we may be looking at the results of a long ago war or terrible accident. Of course, maybe we don't know Jack.

  • by Anonymous Coward

    Seriously? Like they'd sit around in their labs all day doing nothing but now! - oh noes, they are forced to reexamine theories! Yup, that's not at all what science is about.

    In other news: Programmers forced to refactor ancient code!

  • They won't be reexamining much for very long if they keep standing in the light of a massive gamma-ray burst (by which, of course, I mean that it's hard to take the time to examine anything if you're constantly flipping out and going on green-skinned rampages).

  • There is a Google Hangout with the principal investigators on this going on right now. Search for "supernova" in Hangouts or catch the YouTube later.
  • the model for GRB's is not one that's been carved in stone. to be honest, GRB's are not very well understood. the reason for this is that you have to be lucky to detect one AND then be fast enough to point enough telescopes at it to gather enough data for a somewhat stable mathematical model. not so long ago, we didn't really have any clue WTF happened, so I'm not surprised that the models fall short to explain rare occurrences. i've had gamma ray astronomers in the offices next door using satellites like G

  • We are developing this exciting new energy source and will continue testing it in the outer spiral arms of the Milky Way, where there's no intelligent life.

  • Zero Hulks were reported having been seen.
    • Zero Hulks were reported having been seen.

      Just wait for Thanksgiving/Black Friday, they're not under stress yet.

      Also...I for one welcome our green testosterone filled overlords.

  • With Adam, Noach (rhymes with Coach?) and the whole
    Christian Science monitored lot.

  • While typical long-duration bursts last from a few seconds to a few minutes, GRB 130427A put on its display for 20 hours. ... [W]ith GRB 130427A, some of the highest energy photons, including the new record-holder, appeared hours after the blast.

    Maybe light speed varied for particles that arrived here so that "typical" couple minute burst now looks like 20 hour burst ? Reason for that could be particles crossed some dust clowd or some other fenomen.

  • Always proving our theories wrong and making mankind look dumb.

    Heaven forbid our scientific community should just admit 90% of what they "know" is nothing more than a reasonable guess based on virtually no evidence on the cosmological scale.

  • It's clear that our failure to respond to the extraterrestrials shorter burst of gamma rays have led them to try to get our attention with much bigger and more powerful technology.

    Will someone please answer that phone?!

  • Do other distant gamma ray bursts display these odd characteristics, or just this one?

Just about every computer on the market today runs Unix, except the Mac (and nobody cares about it). -- Bill Joy 6/21/85