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Earth Space Science

Earth May Have Been Hit By a Gamma-Ray Burst In 775 AD 157

Posted by samzenpus
from the charlemagne-smash! dept.
The Bad Astronomer writes "Studies of carbon-14 in Japanese trees and beryllium-10 in Antarctic ice indicate the Earth was hit by a big radiation blast in 775 AD. Although very rare, occurring only once every million years or so, the most likely culprit is a gamma-ray burst, a cosmic explosion accompanying the birth of a black hole. While a big solar flare is still in the running, a GRB from merging neutron stars produces the ratio of carbon and beryllium observed, and also can explain why no bright explosion was seen at the time, and no supernova remnant is seen now."
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Earth May Have Been Hit By a Gamma-Ray Burst In 775 AD

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  • by Anonymous Coward

    I thought a nearby GRB would wipe out all life, all the way down to viruses.

    At least that's what Michia Kaku and his bullshit "science" documentaries on Discovery Channel have been telling me.

    • by Electricity Likes Me (1098643) on Monday January 21, 2013 @04:47PM (#42650725)

      Depends on intensity I imagine. The article notes it had to be further then 3000 light years away or they'd have expected it to cause an extinction event - and also that there are "short" and "long" GRBs.

      • It is also very likely to be far away because the gamma ray burst is thought to be generated along the axis of the rotating star. So the chance that a nearby star will happen to point exactly towards us is very low indeed. http://en.wikipedia.org/wiki/Gamma-ray_burst [wikipedia.org] One that might be a danger at some point apparently is http://en.wikipedia.org/wiki/WR_104 [wikipedia.org] but most likely it is angled more like 30 degrees to us so not a danger (just summarizing the info you find on wikipedia about them)
    • by Chris Burke (6130) on Monday January 21, 2013 @04:58PM (#42650841) Homepage

      I thought a nearby GRB would wipe out all life, all the way down to viruses.

      It would. But if it was farther away, it would just create a bunch of radioactive isotopes in the upper atmosphere while leaving life on the ground mostly unmolested.

      If only someone had an estimate of how far away this one was, and had presented it in something that would describe this news item in detail. We could call it an "article".

      For non-douches who also didn't RTFA, it's estimated at 3000 to 13000 ly away. For comparison, in Phil's book "Death from the Skies" he discusses what would happen as a result of a GRB from 100 ly away, and the result is Very Bad(tm).

      • by Kjella (173770) on Monday January 21, 2013 @05:51PM (#42651291) Homepage

        For comparison, in Phil's book "Death from the Skies" he discusses what would happen as a result of a GRB from 100 ly away, and the result is Very Bad(tm).

        Of course for all the preppers out there it should also be said that the closest confirmed GRB is 1.3 billion light-years from Earth, the observation period isn't very long but it's hardly a common occurrence. Which is also why I'm a little sceptic that we've had one right on our doorstep only a few thousand light years away.

      • by mikael (484) on Monday January 21, 2013 @07:16PM (#42652003)

        There was another event that led to modification of the natural isotopes in North America:

        http://ie.lbl.gov/paleo/paleo.html [lbl.gov]

        http://abob.libs.uga.edu/bobk/nuclear.html [uga.edu]

      • by melikamp (631205)
        I think even a nearby long GRB would only fry half the planet, being 30 seconds long.
        • Re: (Score:3, Informative)

          by Chris Burke (6130)

          Well, IIRC from the book, basically everything on the facing side of the earth would be dead and on fire. It would also entirely destroy the ozone layer in that hemisphere. Once the atmosphere had equalized, what would be left wouldn't be enough to protect the survivors from the sun, so they'd all die too, just more slowly and painfully.

          • by tragedy (27079)

            Half the world on fire is still only half the world on fire. This planet is broken up into land masses separated by ocean. There would be a lot of soot and byproducts causing terrible air quality, and probably some "nuclear winter" style weather for a while. Lots and lots of things would die, but certainly not everything. As for the loss of the ozone layer, the soot would probably make up for that. The ozone layer would recover and animals would modify their behaviour to avoid excessive sun damage in the me

            • by Chris Burke (6130)

              Half the world on fire is still only half the world on fire. This planet is broken up into land masses separated by ocean.

              If the earth were oriented favorably such that only some of the landmasses were facing, rather than parts of all of them, that would be helpful, yes.

              As for the loss of the ozone layer, the soot would probably make up for that. The ozone layer would recover and animals would modify their behaviour to avoid excessive sun damage in the meantime.

              You are grossly underestimating the time it would take for the ozone layer to recover from this kind of depletion, and how devastating the sun's UV would be without it. The ozone layer hasn't fully recovered since the CFC ban in the 90s and that was comparatively tiny. More than half the ozone layer would be gone (because the ozone layer is in the upper atmos

              • If the earth were oriented favorably such that only some of the landmasses were facing, rather than parts of all of them, that would be helpful, yes.

                OK - I give up after much staring at a globe ...

                I can get the Pacific Rim on one side ... so Asia, Australia and North America but can not for the life of me see how you would extinct Europe and particularly Great Britain.

                Or I can center Sri Lanka and wipe out Australia, Africa, Asia and possibly Europe ... but not a hope of impacting the Americas.

                Or center the Antarctic and EurAsia is safe.

                Or center Northern Europe, I get everything except SE Asia ... Indonesia, Malaysia, Australia, etc

                etc ... etc

                How woul

                • Use a map instead of a globe. Makes it much easier. :P
                • by Chris Burke (6130)

                  You don't need to get Asia and Europe, they're connected.

                  There will always be islands on the far side of the GRB and far enough from the major landmasses that there's little chance the global-scale fires would reach them.

                  That's really a secondary effect to death-by-Sun.

              • by tragedy (27079)

                The soot clearly wouldn't provide protection for long, I certainly concede that. Just how completely the ozone layer would be depleted isn't really clear, however. Even in a worst case scenario, loss of the ozone layer doesn't mean all UV light gets through. The UVC gets blocked by the rest of the atmosphere regardless, the major rise would be in UVB. The direct effects would be very bad for the short term and long term health of non-nocturnal land animals incapable of finding shelter. The nocturnal ones or

      • by ignavus (213578)

        If only someone had an estimate of how far away this one was, and had presented it in something that would describe this news item in detail. We could call it an "article".

        I would still call it an article if it just contained the word "the".

    • I've heard the 775 C14 anomaly attributed to a very large solar storm period too, even those these guys dismiss the idea.
      • Re:93 million miles (Score:4, Informative)

        by smpoole7 (1467717) on Monday January 21, 2013 @06:57PM (#42651847) Homepage

        > I've heard the 775 C14 anomaly attributed to a very large solar storm period too, even those these guys dismiss the idea.

        The article claims that it would have to be 10 times more intense than any solar storm ever recorded. The article admits that it's a possibility, but (for various reasons) unlikely.

    • It would be pretty grim for anything near the surface.

  • by Anonymous Coward

    The Incredible Hulk was hit by a gamma-ray burst in 1962 AD.

  • by Anonymous Coward

    became ye olde incredible hulke...

  • by Anonymous Coward on Monday January 21, 2013 @04:49PM (#42650735)

    But you not like earth when EARTH ANGRY! RAAWWWRR

    • What more do we have to do to annoy it?

      We've been drilling into it, scooping out large parts of it, flooding parts, draining parts, sucking stuff out of it, injecting stuff into it, etc...

      I suppose if we actually built those 'elevators' from the new Recall movie, that might do the trick.

  • by oodaloop (1229816) on Monday January 21, 2013 @04:53PM (#42650801)
    Did we get struck twice in 775? I bet samzenpus knows.

    http://news.slashdot.org/story/12/06/04/1147201/what-struck-earth-in-775 [slashdot.org]
    • Well, at least the dupes are a half year apart now...

    • by PipianJ (574459)

      If samzenpus doesn't know, Soulskill might. I heard he even has a hypothesis as to what happened then!

      http://science.slashdot.org/story/12/06/28/1356230/has-a-biochem-undergrad-solved-a-cosmic-radiation-mystery [slashdot.org]

      • This link also makes clear that the press release referenced in this submission got the Anglo-Saxon Chronicle date wrong, saying it was 776 when it is actually 774 and therefore *is* a valid candidate for the explosion. Has anyone fired up Stellarium yet to check out the area of the western sky after sunset as viewed from Britain in 774?

    • Hmmm. This event: Black hole formation or giant solar flare.

      Other article: C14 creation: Supernova or giant solar flare.

      I hereby declare the 775 event a giant solar flare.

      • by smpoole7 (1467717)

        > I hereby declare the 775 event a giant solar flare.

        I can't remember if the article specifically mentions this (yes, I did read it), but you'd think that someone would have recorded the event. We have some half-decent written records from that period, from the Chinese, if nothing else. If it was a solar event, you'd think we'd have the Mother Of All Auroras in the sky that evening. Surely someone would have noted it?

        After all, the Crab Nebula was finally declared as the probable result of a supernova ex

  • by Scutter (18425) on Monday January 21, 2013 @05:02PM (#42650881) Journal

    ...why everything tastes like blue.

  • Now we know (Score:5, Funny)

    by Anonymous Coward on Monday January 21, 2013 @05:06PM (#42650897)

    They were really the Glow-In-The-Dark Ages.

  • by JerryLove (1158461) on Monday January 21, 2013 @05:07PM (#42650911)

    FTA: "In the last 3000 years, the maximum age of trees alive today, only one such event appears to have taken place."

    The actual oldest trees are about 5,000 (http://en.wikipedia.org/wiki/List_of_oldest_trees)

    Though that doesn't devalidate his main point (that this has only happened once in 3,000 years). I just wish he'd fact-check a bit more.

  • Clearly, it must have been aliens! [knowyourmeme.com]

  • by MichaelSmith (789609) on Monday January 21, 2013 @05:27PM (#42651081) Homepage Journal

    Neither of the articles discuss what might have happened to living things at the time. Could some people have had radiation sickness for example? Could this have caused mutations?

    • by Megahard (1053072) on Monday January 21, 2013 @05:42PM (#42651185)

      It killed off all the creatures that only lived back then - dragons, elves, fairies, witches and the like.

    • by reverseengineer (580922) on Monday January 21, 2013 @06:18PM (#42651525)

      According to this article [nature.com] from last year on the same event, the event caused an increase in the concentration of carbon-14 in the atmosphere of about 1.2%. That's apparently about 20 times the normal rate of variation, but the baseline level of carbon-14 is about a part per trillion, so we'd be talking about increasing the concentration of carbon-14 by about 10 parts per quadrillion. In contrast, the period of above-ground nuclear testing almost doubled the concentration at its peak in the early 1960s.

      Given our indirect knowledge of the event in 775, it's unknown whether other radiological hazards would have been present in addition to the C14 spike, but there don't seem to be indications of mass dieoffs or famines.

  • that's older than one day.

  • Or else they would have come alive & trapped Emilio Estevez in a gas station.
  • http://en.wikipedia.org/wiki/774%E2%80%93775_radiation_burst [wikipedia.org]

    The part about witness accounts to a red cross like image in the sky, meaning someone may have actually seen the event...

  • Article says 3000 years is the maximum age for trees. http://en.wikipedia.org/wiki/Old_Tjikko [wikipedia.org] http://en.wikipedia.org/wiki/List_of_oldest_trees [wikipedia.org]
  • I just skimmed two-thirds of the comments here. AFAIK, no one read the link.

    To sum up: they say the event they think occured was between 3k and 12k ly away.

    Oh, and Michio Kaku is a better physicist than you are, regardless of what he dumbed down for the whatsit channel.

                mark

  • It seems to be possible to use space based solar power to displace fossil fuels. The concept is to bootstrap by building one power satellite with conventional rockets and equip it with propulsion lasers. The laser is used to heat hydrogen reaction mass in a fleet of vehicles. The improved performance drops the cost of building power satellites to where they undercut coal by half. With that much of an advantage, energy from space would rapidly take most of the market.

    However, a GRB like the 774-775 ev

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