From the AGU weekly highlights:
Large solar proton event explains 774-775 CE carbon-14 increase
Tree ring records indicate that in 774-775 CE, atmospheric carbon-14 levels increased substantially. Researchers suggest that a solar proton event may have been the cause. In solar proton events, large numbers of high-energy protons are emitted from the Sun, along with other particles. If these particles reach Earth’s atmosphere, they ionize the atmosphere and induce nuclear reactions that produce higher levels of carbon-14; the particles also cause chemical reactions that result in depletion of ozone in the ozone layer, allowing harmful ultraviolet radiation to reach the ground.
A previous group of researchers suggested that to cause the observed eighth century carbon-14 increase, a solar proton event would have had to be thousands of times larger than any that has been observed from the Sun. However, Thomas et al. believe that group’s calculations were incorrect. They modeled the atmospheric and biologic effects of three solar proton events with different energy spectra and fluences (number of protons per area). They find that an event with about 7 or more times greater fluence (depending on the spectrum) than an observed October 1989 solar flare event could explain the 774-775 CE carbon-14 enhancement. With a hard (high-energy) spectrum, an event with this fluence would result in moderately damaging effects on life but would not cause a mass extinction. They rule out an event with a softer spectrum because such an event would cause severe ozone depletion and mass extinction, which were not observed in the eighth century. The authors estimate that solar proton events of this magnitude occur on average once in a thousand years, and more often if the estimate is based on astronomical observations of flares on Sun-like stars. They note that although that may seem low, such an event would have severely damaging effects on the technology on which society relies.
Source:
Geophysical Research Letters, doi:10.1002/grl.50222, 2013 http://onlinelibrary.wiley.com/doi/10.1002/grl.50222/abstract
Title:
Terrestrial effects of possible astrophysical sources of an AD 774-775 increase in carbon-14 production
Abstract:
We examine possible sources of a substantial increase in tree ring14C measurements for the years AD 774-775. Contrary to claims regarding a coronal mass ejection (CME), the required CME energy is not several orders of magnitude greater than known solar events. We consider solar proton events (SPEs) with three different fluences and two different spectra. The data may be explained byan event with fluenceabout one order of magnitude beyond the October 1989 SPE.Two hard spectrum cases considered here result in moderate ozone depletion, so no mass extinction is implied, though we do predict increases in erythema and damage to plants from enhanced solar UV.We are able to rule out an event with a very soft spectrum that causes severe ozone depletion and subsequent biological impacts.Nitrate enhancements are consistent with their apparent absence in ice core data. The modern technological implications of such an eventmay beextreme, and considering recent confirmation of superflares on solar-type stars, this issue merits attention.
Authors:
Brian C. Thomas, Keith R. Arkenberg and Brock R. Snyder II: Department of Physics and Astronomy, Washburn University, Topeka, Kansas, United States;
Adrian L. Melott: Department of Physics and Astronomy, University of Kansas, Lawrence, Kansas, United States.
Alberta Slim says:
March 12, 2013 at 8:32 pm
“Vuk is behaving himself [for a change].”
That remark is in itself arrogant and condescending.
It was meant that way. What’s in it for you that you should complain?
wow, great thread! mix of science and spirituality and good humour (mostly), which is catnip for mois.
speaking of ‘proton events’ though, I see we’re likely to be clipped by a filament erupted this morning from somewhere near SS 1690 and 1691, sometime around midnight UT – 1:00 UT on the 14th…expected long duration C-class. And yet another event about an hour ago (2:45 UT) from SS 1692, but not clear where it’s headed. Gonna check Stereo Behind COR2 imagery, and the density and radial velocity on the CME predictor, though I doubt that’s updated yet.
Nice pics here: – http://www.solarham.net/
make that 1:00 to 3:00 UT on 15th and this evening’s was also a long duration C-class.
So far no worries. Feed the horses though. 😉
I’ve always wondered about Carrington level events – – modern cars lack ‘points’ (remember those, anyone?) to replace, rather computers only for ignition. Would a hi-level X-class light up the circuit boards enough to fry, even if turned off? Makes for an interesting mental picture, if several hundred million cars can’t be started (except those parked in Faraday cages, I suppose… ;-))
Something about the Dr M Kaku audio clip posted, that I don’t get/understand: – He mentions ‘eight minutes’ later… I get ( I think) that X-rays move quick, flare-wise, and that CME’s can, on rare occasion, hit 1/4 speed of light, but isn’t it true that CME’s are moving about 500 km second, so we’d have a day or two before things start interacting with our magnetic field?
And on the positive side, isn’t it true there’s some evidence that our field has some sort of ‘muting’ effect the facing sun’s SunSpots? As yet fully understood, that is, but I believe it was Maunder who lent weight to this postulate.
Tiburon,
I saw a show on the military channel on which they demonstrated a prototype EMP weapon. The range of the prototype wasn’t that great and the machine was pretty massive, but they drove a modern car through the pulse and while it killed the engine, the car started right back up after. While a Carrington level even is much bigger, the car was only 10-20 meters from the pulse emitter when the device was fired.
My understanding is that a big part of the vulnerability of the power grid is thousands of miles of wire that will act as a massive antenna. The strength of the current surge is proportional not only to the strength of the magnetic pulse, but the length of the affected conductor. I think it is highly unlikely that computer chips not directly connected to the power grid (or something else that will act as a large enough antenna) will be permanently damaged even if active when the pulse hits.
Tiburon says:
March 12, 2013 at 9:14 pm
Would a hi-level X-class light up the circuit boards enough to fry, even if turned off?
No, as the particles will mostly not penetrate the atmosphere and the effect from induction from a rapidly changing magnetic field will be small because the size of the board is small. Telegraph lines were affected back then, because they were looooong.
A highly unlikely but relevent risk: – (the author often references WUWT)
about 6 min.
Tiburon says:
March 12, 2013 at 9:22 pm
Something about the Dr M Kaku audio clip posted, that I don’t get/understand: – He mentions ‘eight minutes’ later…
Yeah, that was kind of nonsense too. It takes the light 8 minutes to get from the Sun to the Earth [and in those 8 minutes we have no idea what is going to hit us]
CMEs take usually a day or two the reach us. The speed record is 17 hours [Carrington’s was in this class]
And on the positive side, isn’t it true there’s some evidence that our field has some sort of ‘muting’ effect the facing sun’s SunSpots? As yet fully understood, that is, but I believe it was Maunder who lent weight to this postulate.
The Earth field is hundreds of times stronger than the strongest solar wind field so is a pretty good shield. What can cause problems is the electric currents induced in long conductors by rapid changes of the external magnetic field.
CE = Common Era
To remove religious standard, at least in name.
Dr Svalgaard – Thank you. I think I understand. Magnetic induction has to build up over long circuitry, ie power station transformers, transmission lines, and the like, and wouldn’t do so over tiny short length PC chips. That’s a relief then, but I’m still keeping my pocket siphon dust free as I doubt the pumps will be working down at the local Exxon 😉
Nature carried an article last summer on the subject. Hope no one objects. It’s a bit more satisfying than an abstract.
http://www.nature.com/news/mysterious-radiation-burst-recorded-in-tree-rings-1.10768
D.B. Stealey says:
March 12, 2013 at 3:55 pm
Duster says:
“…another good reason to use ‘CE’ is because it is a simple, proper English usage, as opposed to an inverted Latinism, without built-in religious assumptions that irritate Muslims…”
But what if I like to irritate Muslims?
That would be your fatwa 😉
Thank you also, MattS – – two knowledgable opinions make for me, ‘until disproven’ (G-d Forbid, of course, a real world test), fact.
I suppose wel’ll soon be learning much more about what generates Earthly weather, as we begin to understand more about the electrical/magnetic/chemical atmospheric interactions through the levels of the atmosphere from thermopause down to troposphere, in response to ‘inductions’ into our Earth’s magnetic “shield” by the solar “wind” (I’ve learned it’s anything but a ‘wind’, that being just a poor term that got entrenched – but rather charged particles, in arguably varying ‘balances’ between negative and positive charge – hence potentially ‘electrical current’….in turn generating a magnetic field…if one subscribes to that. I do ‘get’ that there’s heated debate as to whether plasma in vacuum can carry current, and cart versus horse debate about magnetic fields in space I’m not qualified to do more than observe at this juncture, while having my ‘suspicions’ about which way it’s leaning)
I find it fascinating, engaging and delightful, and comments like yours and from Dr. Svalgaard, and vukcevic and so many others are constantly expanding my horizons. Thanks!
“””””…..Mike McMillan says:
March 12, 2013 at 3:37 pm
Perhaps the 14C effect could have been achieved by a series of smaller proton events, rather than one large burst.
I note that the politically correct AGU uses Christian Era years, where the abstract uses Anno Domini years. Extra credit to Thomas et al. for placing the AD as a prefix……”””””
And here I thought that CE stood for “Common Era”, and you are telling us it is some religious connotation; so I assume that AD stands for “After the Death”.
Well I hope it gets sorted out soon.
“””””…..D.B. Stealey says:
March 12, 2013 at 3:55 pm
Duster says:
“…another good reason to use ‘CE’ is because it is a simple, proper English usage, as opposed to an inverted Latinism, without built-in religious assumptions that irritate Muslims…”
But what if I like to irritate Muslims?…..”””””
Well when I grew up, they were called Moslems, or Mohammedans, and muslim was a kind of sack cloth material; oh, I suppose that’s why they changed it. Maybe I was lucky to grow up!
“””””…..MattS says:
March 12, 2013 at 9:32 pm
Tiburon,
I saw a show on the military channel on which they demonstrated a prototype EMP weapon. The range of the prototype wasn’t that great and the machine was pretty massive, but they drove a modern car through the pulse and while it killed the engine, the car started right back up after. While a Carrington level even is much bigger, the car was only 10-20 meters from the pulse emitter when the device was fired.
My understanding is that a big part of the vulnerability of the power grid is thousands of miles of wire that will act as a massive antenna. The strength of the current surge is proportional not only to the strength of the magnetic pulse, but the length of the affected conductor. I think it is highly unlikely that computer chips not directly connected to the power grid (or something else that will act as a large enough antenna) will be permanently damaged even if active when the pulse hits……”””””
Well they aren’t likely to affect long distance power transmission lines because those lines are twisted up tightly , so em waves don’t induce any net currents in them of any consequence.
Next time you drive along a freeway with high Voltage transmission lines along it, watch the conductors spiral around each other as you move from pole to pole. Well it may take a mile to make one twist. They are typically three phase, and every few polses they will change the lay of the wires, and slip a third of a twist in; it’s really rather clever how they change the hardware to twist the cables without shorting everything out.
So nyet on the induced em currents. Remember at 60 Herz, the wavelength is 5,000 km, so those HV wires are twisted tighter than a pretzel, maybe 1,000 twists per wavelength.
Tiburon says: “(the author [Suspicous Observa] often references WUWT)”
That is remarkable to hear that SuspiciousObserver “often references WUWT.” If anyone drops by that channel be sure to “reference WUWT” too. Perhaps you might “reference WUWT” and mention that “Greedy Lying Bastards” is a box office fail and WUWT says “When they lie right on the cover, it speaks volumes about the content of the film.”.
Or you might “reference WUWT” to point out that we could actually be producing far more oil and coal than we are. In any event, be sure to “reference WUWT” right back, to return the favor, and enjoy the response. They are going to love you! (:
“Vuk is behaving himself [for a change].”
Yeah, that’ll be the day .
The Earth’s is dancing to the sun’s tune, beyond and above the TSI
http://www.vukcevic.talktalk.net/SGMF.htm
Joe
I agree with you.
“AD/BC has lasted over 2000 years already”, yeah i believe Jesus’ first words were, “This is year zero, I ‘ll explain later…”.
While we wait for a CME hit
Duster says:
March 12, 2013 at 3:34 pm
The entire second half of the first millennium CE is chaotic. It has been suggested that Krakatoa may have erupted on an even greater scale than the 1883 eruption in 535 CE.
—
I saw a show on one of the science channels this weekend that postulated a cometary impact just north of Australia in 535or 536AD. They’ve found two craters that date to that time just off the coast.
Duster says:
March 12, 2013 at 3:46 pm
—
Most of the non-Europeans that I talk to don’t mind the AD convention, they find the CE convention to be just silly and equally Euro-centric, since there is in reality nothing common about it. Every culture has it’s own dating system, it’s quite presumptous of us to proclaim that ours is the common one. It isn’t.
A.D. Everard says:
March 12, 2013 at 5:37 pm
—
The AD/BC system didn’t start until around 400 to 500 AD.
The Christian leaders got tired of numbering time by how long since the most recent Ceaser came to power, so they assigned a monk (who’s name I have forgotten again) to figure out when Christ was born. Given the quality of historical records available to him, he did a pretty good job.