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Fermi and Swift Observe Record-setting Gamma Ray Burst
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."
How close would one of these events have to be to us to fuck us up?
If Slashdot were chemistry it would look like this:Cadaverine
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 should give them dispersion. The best test so far is based mostly on GRB 080916C, 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.
Nope, I am going to go with the scientists here and say its very credible that it was a Galaxy far far away. Also a long long time ago.
So I'm going to further speculate that it was the death star blowing up the Aldebaran system. Or perhaps the deathstar being blown up it self.
Now how the Ewoks would survive such a massive gamma burst is anyones guess.
It happened 3.6 billons of years ago, isn't time to get a bit fresher news?
I believe the Ewoks survive it by chortling, giggling, and jumping up and down. Did you wish to propose an alternative survival method?
Correct Horse Battery Staple: 72 bits of entropy. Enter "Correct H" into google. When it generates the phrase, that's
Very appropriate for Star Wars Day!
On a (very slightly) more serious note, Kardashev type III civilizations might be able to weaponize Gamma Ray Bursts, and take out an entire Galaxy the way the Death Star took out Alderaan. I suspect that even Darth Vader would find that impressive.
How can a photon have volts? Aren't all photons created equal?
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
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
Michael Richmond "This is the heart that broke my finger."
mwrsps@rit.edu http://stupendous.rit.edu
I thought we dodged Betelgeuse in 1988.
Hehe, thanks for catching the misspelling of Alderaan (bad me). I knew I got it wrong. But yeah, I like the Kardashev scale also.
TBH I didn't realize it was Star Wars Day. Though I do like Star Wars quite a bit =) so my coincidental celebration of it is great!
As shown in historical media, the blast of the exploding Deathstar expanded on a two dimensional plane. This plane obviously did not bisect the ewok's midichlorians.
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May the 4th... be with you.
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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.
If it was Betelgeuse, you would know it. It would probably be bright enough to be seen during daylight in the visible light range, let alone invisible GRBs.
Thing is, unless Betelgeuse happened to have it's axis pointed right at us, we wouldn't be hit by a beam of radiation that sometimes forms at the poles of a supernova/black hole. If that beam was not pointed right at us, we are far enough away that the rest of the supernova products would not cause us more than a light show.
Supernovae need to be around 50 light years away or less to cause serious issues for us, unless the energy was very concentrated (like the jets from certain types of black holes). Betelgeuse is not that close. Indeed, no candidates for a supernova are known to be within that radius at this time.
This Gamma Ray Burst (GRB) was stronger than a typical GRB, and a typical GRB is much stronger than a typical supernova, at least in the beam. This paper considers the effects of a GRB at 2 kpc, or 6000 light years, or over 100 times further away than the 50 ly supernova limit. I don't know any details of the new GRB, but if it was as bright as they are implying, it could have been dangerous from the galactic center or beyond.
There is one asterisk here - a supernova will be dangerous for some time (possibly months), while a GRB lasts seconds. A GRB, even if it totally roasts one hemisphere of a planet, would miss the other side, while a SN could get both sides. There might be second order effects from the GRB (such as some sort of nuclear winter) that could cause havoc, but a single GRB just might not be able to totally sterilize a planet from 20,000 light years away. (The 50 ly supernova limit is not that firm, either). We don't know for sure in either case, and I for one would not like to find out.
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.