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Fermi and Swift Observe Record-setting Gamma Ray Burst 107

Posted by timothy
from the where-do-we-send-the-medal? dept.
symbolset writes "Phys.org shares a visual image of a 'shockingly bright' gamma ray burst observed April 27th, labelled GRB 130427A and subsequently observed by ground optical and radio telescopes. One gamma ray photon from the event measured 94 billion electron volts — three times the previous record. The burst lasted four hours and was observable for most of a day — another record. Typical duration of a gamma ray burst is from 10 milliseconds to a few minutes. Astronomers will now train optical telescopes on the spot searching for the supernova expected to have caused it — typically one is observed some few days after the burst. They expect to find one by the middle of May. The event occurred about 3.6 billion lightyears distant which is fairly close as gamma ray bursts go. Click on the GIF to view the actual burst."
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Fermi and Swift Observe Record-setting Gamma Ray Burst

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  • Need expert opinion (Score:5, Interesting)

    by paiute (550198) on Saturday May 04, 2013 @07:55PM (#43632239)
    How close would one of these events have to be to us to fuck us up?
    • by mbone (558574) on Saturday May 04, 2013 @07:57PM (#43632247)

      Anywhere in the Galaxy, if it were pointed in our direction. Maybe anywhere in the Local Group, if it were pointed right at us.

      • by Dunbal (464142) *
        I guess this is probably related to the neutrinos that were detected a few days ago?
        • by mbone (558574) on Saturday May 04, 2013 @09:31PM (#43632493)

          No. They may have detected something, and it's not gone through the pipeline yet, but Bert and Ernie were much before this event.

          They [lanl.gov] were August 8, 2011 (Bert) and January 3, 2012 (Ernie).

            Even if they didn't see a thing, I am sure there will be an IceCube press release about this in a few months, as they will be able to improve the GRB neutrino limit.

        • by mbone (558574)

          This is late, I know, but for the record IceCube (the most sensitive neutrino telescope) has announced [nasa.gov] that it did not see any neutrinos from this GRB,

      • Re: (Score:2, Insightful)

        by Anonymous Coward

        I read 200 light years from a typical supernova lasting a few milliseconds.

      • Re: (Score:2, Interesting)

        by J'raxis (248192)

        Score 5; insightful?

        All the GRBs we see are pointed right at us. They're highly directional; any GRBs that aren't pointed right at us we can't even detect.

        • by fisted (2295862)
          Your point being?
        • by HiThere (15173) <`charleshixsn' `at' `earthlink.net'> on Sunday May 05, 2013 @01:26PM (#43635719)

          IIUC, while any that we can detect are pointed in our direction, there's a lot of halo around the core of the emission. We generally pick things up from that halo, but the core would be a lot more intense. If it were pointed right at us, that would mean that the most intense portion of the beam was pointed at us. There isn't much spread, but the signal has been spreading out slowly for many light-years. (Hundreds? Thousands? Millions? Pick your incident to get your answer.) Even a laser spreads given that much distance. If there's no other reason, then there's bumpy space around stars, and variations in the galactic magnetic field.

          So, yeah, unless they're very close we can't detect them unless they're pointed at us. But the directionality is sufficient that at sufficient distance there's a sufficient spread that most of the space where the signal can be detected is relatively weak compared to the central part of the beam.

          OTOH, this is just "IIUC". I could be wrong. But I don't think so.

      • by dkleinsc (563838)

        If it's pointed right at us, I say we do the only sensible thing and shoot back!

    • If it were pointed right at us, my understanding is our ozone would be ionised pretty quickly. Clearly that would not be a good thing.
      • by Bengie (1121981)
        Depending on close one is, it could ionize our entire atmosphere, not just the ozone. But from what I understand, ionizing a significant part of our ozone is all that is needed to mess things up really badly.
  • by mbone (558574) on Saturday May 04, 2013 @08:19PM (#43632301)

    The brightest Gamma ray bursts (GRB) are important for quantum gravity, as the photons have a short enough wavelength and go over long enough distances that spacetime foam [arxiv.org] should give them dispersion. The best test so far is based mostly on GRB 080916C [skyandtelescope.com], and from what I hear this new burst may be able to do better.

    A little background.

    The Heisenberg uncertainty principle predicts "virtual" particles. The time part of the uncertainty principle is delta T delta E > h, where E is energy, T is time and h is Planck's constant (I am ignoring factors of 2 pi). As the time of an event (say, the time for a photon to travel one wavelength) gets shorter, the energy of the virtual particles allowed (delta E) gets bigger. For short enough time periods (i.e., near the Planck time), the energy is enough that the virtual particles are black holes, popping in and out of existence, and severely mangling the spacetime on that time / distance scale. This mangling is called "spacetime foam". The wavelength of the GRB photons is much larger than the Planck distance (roughly, the virtual black holes should live for a Planck time and have an event horizon the size of the Planck distance), but the GRBs are very far away, and the GRB photons pass over many, many, Planck distances along the way, and each adds a little nudge. This effect depends on the photon energy (it is larger for higher energies, as these are smaller photons), thus the "dispersion" mentioned in these papers.

    The really cool thing is that the existing dispersion limits seem to be less than many people's expectations. If this is confirmed (and pushed down to a little smaller distance scale), then the conventional spacetime foam ideas I outlined above here may not be correct. This, in fact, may be the first evidence for the "holographic principle," which implies a smoother spacetime than the above ideas. In any case, this is the only way we have at present to say anything experimental about quantum gravity, so the more data the better.

    • by Ultra64 (318705) on Saturday May 04, 2013 @08:40PM (#43632347)

      Mmm, hmm. I recognize some of these words.

      • Re: (Score:3, Funny)

        by rmdingler (1955220)
        Thank you, kind sir, for the much needed belly laugh!
    • by KGIII (973947)

      Thank you.

    • by MickLinux (579158)

      So basically, the spacetime foam theory is not playing out?

      That's comforting, because it implies that the Heisenberg uncertainty principle is a bit more mundane than we think. I like to take it as an experimental practicality to "energy can be neither created nor destroyed"; but what I like is irrelevant to reality. However, if the spacetime foam is invalid, then the reality happens to be closer to what I imagine: a definition of existance and indeed space based on interactions between energetic particles,

      • by mbone (558574)

        So basically, the spacetime foam theory is not playing out?

        It's too soon to be sure, but, as the paper says,

        Such limits constrain dispersive effects created, for example, by the spacetime foam of quantum gravity. In the context of quantum gravity, our bounds set M1c2 greater than 525 times the Planck mass, suggesting that spacetime is smooth at energies near and slightly above the Planck mass.

        That sure isn't what I would expect. Now, maybe the current thinking (really, just dimensional analysis) is missing something important, but if we can push that "slightly abov

        • by MickLinux (579158)

          Got a question : as a proton, one among many, accelerates into a black hole, what is going on with the individual quarks? What shape do they form? What virtual particles are materialized, in what pattern? What structure do they develop?

          • by mbone (558574)

            Got a question : as a proton, one among many, accelerates into a black hole, what is going on with the individual quarks? What shape do they form? What virtual particles are materialized, in what pattern? What structure do they develop?

            Don't know. Nobody knows.

            In GR, nothing much, until they fall into the singularity at the center of a black hole (although tidal forces would rip even a proton apart as it got close to the singularity, and that would generate a lot of particle production). At the singularity itself, the equations fail, and so GR makes no predictions.

            In string theory there may be holographic effects that turn the event horizon into a "firewall," which has been in the scientific news a lot lately (search on "black hole firewa

            • by MickLinux (579158)

              Well, consider this: whichever quark (R/G/B) is closest to the black hole, will experience the greatest acceleration. Therefore, it will be accelerated away from the other two, until the energy is enough to cause particle/antiparticle pair creation. But the particle/antiparticle pair will also be created between the quark and its partners... therefore, you will not get pair annhiliation of the outer two. The new pair can't catch the old pair.

              Still, any distance between the new quark/antiquark (say, R/*R

    • I do very casual reading on such topics, the stuff generally meant for the layman. Since you appear to be much more knowledgeable, maybe you can answer this for me: any chance this could be a signal from evaporating primordial black holes? What kind of signal do we expect to see for those? Other than not finding a supernova in the direction of the burst, that is.
      • by mbone (558574) on Sunday May 05, 2013 @09:32AM (#43634365)

        No, although that was entertained (by some) in the fairly long history of these bursts.

        In the early days (after GRB were detected by US satellites sent up to look for nuclear explosions) there were lots of theories, as we knew basically nothing about them. The consensus was that GRB were probably fairly close to us, in the galaxy (which kept the burst energy reasonable). The early satellites could only see the brightest bursts, so there weren't many bursts observed, and statistics were very poor, so you couldn't say much more. (At this time I remember some people proposing primordial black hole explanations.) One of the major goals of the Compton Space Telescope BATSE experiment was to be sensitive enough to GRB to be able to observe hundreds to thousands of them, with decent positions, enough data so that you should be able to see the Milky Way (the galactic disk) in the burst locations (i.e., that you would see more bursts along the Milky Way in the sky than in other directions). At the time, the consensus opinion was very strongly that BATSE would see the plane of the Milky Way in the aggregate burst positions, as they accumulated.

        The experiment was flown and worked well and recorded an isotropic (random) distribution of bursts. (So much for conventional wisdom.) This meant that the bursts were either very far away (and thus very powerful) or very close (and thus relatively weak, weak enough that you could only see them up to a few light years, where everything is in the galactic disk, and thus can look random in direction, the way the brightest stars in the night sky appear more-or-less random in direction). I actually toyed around with an extraterrestrial intelligence explanation for close bursts at that time (the bursts would be some side effect of power generation or space travel, which would have implied that the ETIs were close and ubiquitous), but most people started thinking about extremely distant (to be random), and thus very powerful events. (IIRC, this was bad but not quite fatal for the primordial black hole explanation, as those bursts are strong enough that you would expect to see the galactic disk in the accumulated BATSE data, but maybe you could adjust things enough to get around that.)

        This conundrum was resolved by the orbiting Swift telescope, which could not only see GRB, but could report a position back to Earth quickly enough to train an optical telescope on the spot within a few seconds. This was flown, and some GRBs were observed in the optical. (This also required some serious work on rapid response optical telescopes.) Swift + optical meant that we knew their positions very accurately, so the biggest telescopes could be used to see where, exactly, they were coming from (which turned out to be distant galaxies) and thus get a red shift, and thus a distance (the GRB of the OP is apparently at a red shift of 0.34). That, among other things, showed very clearly that these bursts could not be primordial black holes (or local ETI!), as those are much too weak to see bursting across cosmological distances.

    • by cundare (1141279)
      Interesting, but what do you mean when you say that the virtual particles are "black holes"? Stellar black holes have a heckuva lot of unusual characteristics -- which ones do you reference here?
      • by mbone (558574)

        This is very late, but just in case, a brief answer.

        The virtual particles in question would be massive enough and small enough that in GR they would be full fledged black holes.

  • by Anonymous Coward on Saturday May 04, 2013 @09:33PM (#43632499)
    It happened 3.6 billons of years ago, isn't time to get a bit fresher news?
  • How can a photon have volts? Aren't all photons created equal?

    • by Dunbal (464142) *
      electron volts, not volts. Wikipedia is your friend. It's how energy is measured when you talk about small things.
    • by femtobyte (710429) on Saturday May 04, 2013 @10:02PM (#43632581)

      "electron volt" is a unit of energy --- specifically, the energy required to move one electron charge across one volt of electrical potential. 1 joule is ~6.2*10^18 electron volts. And no, all photons aren't "equal" --- they have different energies (equivalently, different wavelengths, frequencies, momenta, or colors for visible-range photons). For comparison, visible light photons are ~2 electron volts energy.

    • Colour (Score:4, Funny)

      by Roger W Moore (538166) on Saturday May 04, 2013 @11:32PM (#43632833) Journal

      Aren't all photons created equal?

      No, that was the early black and white universe: for the last 13.8 billion years we've had colour.

    • by Bengie (1121981)
      All photons of the exact same frequency are equal. Higher frequency GRB photons are more equal than lower frequency ones. They are the 0.1%.
  • by StupendousMan (69768) on Saturday May 04, 2013 @09:55PM (#43632557) Homepage

    I wrote up a short summary of the observational details for one of my classes -- you can find it at

    http://spiff.rit.edu/classes/phys443/lectures/grb130427a/grb130427a.html [rit.edu]

    You can also follow a nice summary of the latest results by following Don Alexander's thread on the Cosmoquest forum:

    http://cosmoquest.org/forum/showthread.php?143754-GRB-130427A-burst-of-the-(quarter)-century [cosmoquest.org]

  • I have just imagined http://en.wikipedia.org/wiki/Enrico_Fermi [wikipedia.org] and http://en.wikipedia.org/wiki/Jonathan_Swift [wikipedia.org] looking at a supernova. Maybe someone can guess what they would say to each other about it, but I have no idea.

  • wavelength (Score:4, Informative)

    by Spinalcold (955025) on Sunday May 05, 2013 @01:59AM (#43633215)
    To me one of the most surprising things is the wavelength. Back of the envelope calculation gives me 4.4 *10^-26m. That is amazingly small, 8 orders of magnitude smaller than the proton. This also came from 1/4 of the universe away, which makes me wonder how much smaller it is due to the expansion of the universe. Probably not much, but DAMN that is small.
    • Yet still 12 orders of magnitude greater than the Planck size. It is boggling how much we don't begin to know.
      • by mbone (558574)

        Yes. Trying to constrain spacetime foam with these photons (see my post way above) is harder than trying to learn something about atoms using your hands (only 10 orders of magnitude or so), and yet over 3 billion years of travel, even little things add up.

    • by Skapare (16644)

      Should "how much smaller it is due to the expansion" be "how much smaller it originally was before the red-shift expanded it to give us this still amazingly small wavelength" ?

  • a long time ago...The Death Star destroyed a planet, and here is the result, a sudden disturbance in the Force.
    • by Skapare (16644)

      This event seems to be powerful enough to rip part of a galaxy apart, and kill everything that might have been alive in the rest of it. But given how far back in time it is, I don't think life had emerged, yet.

  • The article says it is 3.6 billion light years away. But when is that distance applicable? This event happened long, long ago and we are just now seeing it. But was the 3.6 Gly the distance back when it happened? Or is the 3.6 Gly the distance today, when we see it? Given the purported expansion of the universe, this matters.

    We can see these past events happen because they were far enough away when they happened. We cannot see most recent events because the light has not gotten here yet (unless the ev

    • by mbone (558574)

      Go on the Cosmology Calculator [ucla.edu], put in the red shift (z = 0.34) and (for the default cosmological model, which is pretty good now-a-days) you get

      The light travel time was 3.751 Gyr.

      The comoving radial distance, which goes into Hubble's law, is 1330.7 Mpc or 4.340 Gly.

      The angular size distance DA is 993.0 Mpc or 3.2389 Gly.

      One big question is, how far back can we see. We cannot see back to the big bang, so there is a limit, if we confine the question to seeing events within the mass that emerged from the big

  • I see already some politicians in the US asking for a military intervention to all possible supernovae as they are an external treat to the US...

It was kinda like stuffing the wrong card in a computer, when you're stickin' those artificial stimulants in your arm. -- Dion, noted computer scientist

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