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  1. Did the 12-27-2004 gamma ray burst cause any illness affects upon life on earth?

  2. Do we know what hemisphere of the earth or portions of the earths surface received the highest radiation?

  3. What was the time duration of the radiation as observed on the earth?

If one hemisphere was exposed to the majority of the radiation perhaps a significant disparity in illness after the event is / was measurable

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    $\begingroup$ 230,000+ people were killed around that time because of the tsunami the day before, possibly hampering research on health effects by comparing regions. Time: 21:30 UTC lb.wikipedia.org/wiki/Gammabl%C3%ABtz. With the location en.wikipedia.org/wiki/SGR_1806-20 (Sagittarius), one should be able to work out which hemisphere was facing the blast. fourmilab.ch/cgi-bin/Yoursky gives 35S , 130W facing the blast. That seems south of the Pitcairn Islands. $\endgroup$ – Keep these mind Apr 9 '17 at 17:43
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    $\begingroup$ I'm voting to close this question as off-topic because it is not a question about any concept of physics, it is asking for information about the biological effects of a particular event. $\endgroup$ – sammy gerbil Apr 9 '17 at 20:33
  • $\begingroup$ @sammygerbil - You have a point. But there is some physics on the side. How much radiation is in a burst? How far? Etc. A biology site could make a case for migrating it here. $\endgroup$ – mmesser314 Apr 9 '17 at 20:48
  • $\begingroup$ A neutrino from that burst damaged the DNA of a microbe, causing it to die. $\endgroup$ – Count Iblis Apr 9 '17 at 21:29
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Any health effects were too small to be noticed.

According to this NASA article, the gamma ray burst lasted a few minutes with a peak that lasted 0.1 seconds. That peak was huge, containing all the energy the sun would produce in 100,000 years. It was far brighter than the second brightest short burst.

It was also very close as gamma ray bursts go. Bursts are extremely rare, typically a few per million years in a galaxy. But space is huge. There are enough galaxies that hundreds of bursts a year can be detected. Most are from extremely distant galaxies, and are so faint they are only noticeable to sensitive instruments in space designed to detect them. This was from the far side of our galaxy, "only" 50,000 light years away.

So the peak power outdid the sun by a factor of $3 * 10^{13}$. The distance was $3*10^{9}$ times farther than the sun. The upshot is the intensity was $3*10^{-6}$ as bright as the sun. However this was gamma rays. In the gamma ray spectrum, the burst was brighter than the sun. Gamma ray detectors in space were saturated. There were strong effects in the upper atmosphere.

Earth's atmosphere does a really good job of shielding us from the primary gamma radiation. However gamma rays excite UV radiation that does reach the surface. But it was faint, not nearly strong enough to cause, say, a suntan.

Any long term health effects would be from damage to the atmosphere. Gamma rays ionize molecules. Models show this produces nitrogen oxide and nitrogen dioxide. This can deplete ozone, create photochemical smog, and cause acid rain. Smog could darken the sky, reducing photosynthesis and causing global cooling. If bad enough, it would take years to recover.

In this case, ionization was significant down to an altitude of 20 km, just above where commercial airlines fly. At 60 km, ionization changed from 0.1 free electrons per cubic foot to 10,000. It took an hour for ionization to recover.

The disruption of the ionosphere was enough interfere with communications. The ionosphere is the highest part of the atmosphere, nearly vacuum. Radiation ionizes molecules, and air is so thin that it takes a long time to recombine. Ions are conductive, so radio waves are reflected. The ionosphere forms a wave guide. This can be used to talk over the horizon. When the burst ionized the atmosphere down to 20 km, the wave guide changed.

Here are a few links - A Gamma-ray burst Wikipedia article talks about bursters in general. The difference between long and short bursts. Potential effects of life on Earth. Possibilities that Ordovician-Silurian extinctions 450 million years ago might fit the profile of a gamma ray burst.

SGR 1806-20 is a short Wikipedia article on the neutron star where the burst originated. Neutron stars can have immensely strong magnetic fields. This star has the strongest - $10^{11}$ Tesla, 1000 times stronger than a typical neutron star. Compare it to a strong superconducting magnet with 10 Tesla.

Big gamma-ray flare from star disturbs Earth's ionosphere is an article from Stanford Digest on the effects of this burst.

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  • $\begingroup$ "The star responsible for the 2004 burst was about the same distance as the star responsible for the 1998 burst but was within 5 degrees of the sun as viewed from Earth. Therefore its gamma rays arrived on the day side of our planet. Neither star's gamma rays reached the Earth's surface, according to Inan. Neither flare posed a danger to people, he said." This seems quotable in the answer. $\endgroup$ – Keep these mind Apr 9 '17 at 18:17
  • $\begingroup$ "Bursts are extremely rare, typically a few per million years in a galaxy." These are different from the much more frequent events (flares?) in our galaxy. $\endgroup$ – Keith McClary Apr 9 '17 at 20:57
  • $\begingroup$ @KeithMcClary - See this - en.wikipedia.org/wiki/Gamma-ray_burst_progenitors. This burst is described as a rare kind of flare. But most are not. $\endgroup$ – mmesser314 Apr 9 '17 at 23:56

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