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Iron Age Potters Accidentally Recorded the Strength of Earth's Magnetic Field (npr.org)
Solandri writes: We've only been able to measure the Earth's magnetic field strength for about two centuries. During this time, there has been a gradual decline in the field strength. In recent years, the rate of decline seems to be accelerating, leading to some speculation that the Earth may be losing its magnetic field -- a catastrophic possibility since the magnetic field is what protects life on Earth from dangerous solar radiation. Ferromagnetic particles in rocks provide a long-term history which tells us the poles have flipped numerous times. But uncertainties in dating the rocks prevents their use in understanding decade-scale magnetic field fluctuations.
Now a group of archeologists and geophysicists have come up with a novel way to produce decade-scale temporal measurements of the Earth's magnetic field strength from before the invention of the magnetometer. When iron-age potters fired their pottery in a kiln to harden it, it loosened tiny ferromagnetic particles in the clay. As the pottery cooled and these particles hardened, it captured a snapshot of the Earth's magnetic field. Crucially, the governments of that time required pottery used to collect taxed goods (e.g. a portion of olive oil sold) to be stamped with a royal seal. These seals changed over time as new kings ascended, or governments were completely replaced after invasion. Thus by cross-referencing the magnetic particles in the pottery with the seals, researchers were able to piece together a history of the Earth's magnetic field strength spanning from the 8th century BCE to the 2nd century BCE. Their findings show that large fluctuations in the strength of the magnetic field over a span of decades are normal. The study has been published in the journal PNAS.
Now a group of archeologists and geophysicists have come up with a novel way to produce decade-scale temporal measurements of the Earth's magnetic field strength from before the invention of the magnetometer. When iron-age potters fired their pottery in a kiln to harden it, it loosened tiny ferromagnetic particles in the clay. As the pottery cooled and these particles hardened, it captured a snapshot of the Earth's magnetic field. Crucially, the governments of that time required pottery used to collect taxed goods (e.g. a portion of olive oil sold) to be stamped with a royal seal. These seals changed over time as new kings ascended, or governments were completely replaced after invasion. Thus by cross-referencing the magnetic particles in the pottery with the seals, researchers were able to piece together a history of the Earth's magnetic field strength spanning from the 8th century BCE to the 2nd century BCE. Their findings show that large fluctuations in the strength of the magnetic field over a span of decades are normal. The study has been published in the journal PNAS.
From TFA: ''' "When dealing with such large-scale phenomena, we don't usually think it can occur within a few decades. We usually think it would take thousands or tens of thousands of years," Forman says. The finding, he adds, "opens up a big can of worms" because researchers just don't know how or why that would happen. So there's something missing about scientists' concept of goings on in the Earth's core.''' But hey, at least now we know we don't know :)
+Raider of the lost BBS
How do we boost the strength far enough to eliminate cancer?
Pretty nifty.
I'm a bit miffed about language: "[...] it loosened tiny ferromagnetic particles in the clay. As the pottery cooled and these particles hardened, [...]"
That's a pretty graphic description, but in a geek site... can't we just say Curie point, or Curie temperature?
If we don't keep the standards, who will?
(If you think some jargon is exclusive: insert a link to Wikipedia -- there's, as often, a very nice article on that).
Isn't this actually Paleomagnetism/Archaeology 101? I mean, reconstructing the magnetic field in shape and strength from the finds is a substantial endeavor, but the headline itself is no news to anyone in the field. It's been one of the bog-standard methods of how archaeological sites are surveyed.
Ezekiel 23:20
Then how do you explain the fact that clay with the same seal displays very similar effects, and with different seals display different effects, with the magnitude of the effect lining up with the years indicated by the seals on the pots?
Just a thought
Build a Man a Fire, and He'll Be Warm for a Day. Set a Man on Fire, and He'll Be Warm for the Rest of His Life.
. . . . back in my Geophysics days (early 1980s), we already knew that the current planetary magnetic field was in decline, and we were approaching a pole reversal "real soon now" (in Geologic timeframe, not human timeframe. . ).
Heck, we were routinely measuring fossilized magnetic remnant fields in far older rocks, not just strength, but orientation as well. And finding the proper orientation of the sample was always difficult, generally required microscopic examination of a thin slice of the sample. The advantage of pottery for recent sampling, is that it is far easier to determine the orientation of the sample. . .
There are a lot of red brick houses in the world. If only the date of the building of the house is known and the bricks are not repurposed from other buildings, similar information can be derived.
If they can measure the magnetic properties of the mortar you can even get the direction.
Hmm ... How are you going to determine field orientation at time of cooling below the Curie temperature for pottery? Wouldn't that require knowing the physical orientation of the item when it was being cooled after firing? Am I missing something, like there's a universal point-to-the-east orientation that all pottery is placed in when cooling?
I can see making a good guess for geological structures, but pottery?
Put my fist through my alarm clock with its ding-dong death inside my ear. - The Blackjacks.
Multiple samples from independent sources and locations help mitigate those concerns, along with a slowly-varying time course of the field strength.
What manufacturing circumstances would change the strength of magnetization for ferrous inclusions in cooling pottery that would be present before, say, 0 AD to pick a convenient, arbitrary and approximately relevant threshold?
Put my fist through my alarm clock with its ding-dong death inside my ear. - The Blackjacks.
How does the change in mag field strength jive with warming or cooling of Earth? Does the extra solar radiation heat us any?
"... to some speculation that the Earth may be losing its magnetic field -..."
Since the data ultimately suggests that fluctuations are completely normal, I submit that this also starts to explain why people are taking scientists less and less seriously.
Don't blame this on the researchers; blame this on the "science writers" (including the author of the summary here on Slashdot). The actual study - at least the abstract and the supplemental material, which was all I could read without a PNAS subscription - says no such thing and that particular wording is just a click-bait addition in order to garner more views. Science journalism - like so much journalism this day - has gone on a real decline over the past twenty years and tries to "spice up" every study rather than simply reporting the science. The end result is that scientists end up sounding inconsistent and hyperbolic ("Coffee Cures cancer!", no wait, "Coffee Causes Cancer"), when they usually are neither; it is the people reporting on their work that are to blame.
Also see for a more graphic comment on the same problem.
It's in the actual paper - unfortunately it seems paywalled, I don't know if there's an arXiv equivalent for this stuff but the table on page 4 is pretty conclusive - about 100 samples split into age categories based on their stamps.
Language, folks. Accidents are things you want to avoid, not things you just don't realize.
It really isn't that hard to consult a dictionary rather than impulsively posting something that turns out to be mostly incorrect. There are seven meanings for the word "accident" here, and five of them have no negative connotation at all. Several indicate it's a synonym for the things you say it doesn't mean.
Well, assuming you know the shape of the original pottery, or better still, have a whole piece or enough to reconstruct: simply MEASURE the orientation, then use paleomagnetic detection techniques to measure the remnant field. Then compare the observed field orientation against the physical orientation of the sample
Yes, words have meanings. Often, as in the case of "accident", words have more than one meaning. One of the meanings of "accident" is "any event that happens unexpectedly, without a deliberate plan or cause." In other words, "inadvertent".
Accidentally is an appropriate word in this context. It refers to something that happened by chance or was fortuitous. You do not specifically have to be trying to avoid something for it to be accidental. English is a wonderful language that has many ways to say the same thing.
Fluctuations in past magnetic field on decade basis was hard as heck to measure on short period basis, because it takes solidifying rock/clay to lock the magnetic particles, and these don't form neat linear progression over time - the stamped pottery was the first that allowed to set samples in chronological order with decade dating precision.
Past global temperature is much easier to estimate, as its 'records' are 'frozen' as yearly growth of trees; each ring recording how warm and how dry the year was, through changing cellular structure and amount of growth. Fossilized trees allow to determine that, year by year; and events like volcano eruptions depositing specific unique substances in given year's ring across all tree population of given world area allow correlating samples of different age. Similarly deposits at bottoms of lakes create similar records.
In other words: we *just* discovered wild fluctuations in magnetic field. Meanwhile, for a long time, we have *known* there were no similar fluctuations with global temperature.
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We need a new protocol that redistributes money from wealthy countries to poor ones who will be most affected by the loss of the magnetic field because the wealthy ones have a lot more electric motors and refrigerator magnets so they're ruining the Earth's field.
While the situation may be normal regarding Earth's history, and in past humanity history it would merely mean increased cancer incidence, magnetosphere primarily protects electronics from coronal mass ejections. This has only a history of several decades and was never exposed to diminished Earth magnetic field.
So, no, life on Earth won't be wiped by the demagnetization, and no enormous natural cataclysm will occur. But you might find electronics fried at nuclear power plants affect our daily life, especially when accompanied with fried satellites, fried electronics of tractors farming fields that provide our food, fried hospital equipment, and so on, and so on. The resulting cataclysm would be direct result of our reliance on electronics, the accompanying minor bump in cancer incidence negligible by comparison.
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Considering this is connected with Earth spin, any vehicle traveling east, pushing itself against the ground/water/air, is slowing Earth spin, while travel west increases it.
So we should tax all eastward travel and use the money to subsidize westward transportation.
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Before Common Era? WTF? As opposed to an "uncommon" one?
OK, I'm a (kinda) scientist, so I should maybe be "against" all the religious stuff, but I have no problem with "Before Christ" just as I have no problem with V for Volt(a) or A for Ampere. (Grant you, these were real people, and real scientists too...)
FFS, it's not like "BC" is insulting to Muslims or other people who use a different calendar (many also religion-based), since they're not aligned with the same time period. /rant
If anything, "BCE" seems more insulting, since it implies that their alternative calendars are "not common"...
I agree that if they prove a tight correlation it means something. I can't see anything about that in the links though, so is this an article which proceeds from the assumption that the correlation with earth magnetism is very tight(if we assume correlation is tight then we can conclude magnetic field has decreased 30%), or does it prove the tight correlation as well. There is statistics involved and I can't see what kind.
Testing that correlation can also be done with experiments today with new pottery. Have such experiments been done? I take it that fast variability of the earth magnetic field exists is already a given, because I doubt if old pottery by itself will carry enough weight to prove that the magnetic field can change quickly.
Well, as other posts have already replied to you, the strict distinction you're trying to make here doesn't really hold in English. Both accidentally and inadvertently can easily apply to something that was trying to be avoided.
But I sense a problem with the headline too, and I think the real issue is -- why are the POTTERS mentioned at all? There's a kind of implication with the way the headline is worded that the potters "recorded" information, except they had no concept of what such recording might amount to or what that information might be. Really, the potters had no intentionality here at all.
This is even worse in the original NPR headline, which is "Iron Age Potters CAREFULLY Recorded Earth's Magnetic Field -- By Accident." That's more problematic from an English usage standpoint, because "carefully" implies they did something with care... specifically they "recorded" with care. But they didn't know they were recording anything, so how could they do it with care?
The more clear way to word all of this would of course be to take the potters out of it completely, since they weren't "recording" anything -- intentionally or unintentionally. They were making pottery. A better headline might just be "Strength of Earth's Magnetic Field Recorded in Structure of Iron Age Pottery" or something. Even better, leave "record" out of it entirely, since that usually implies intentionally preserving information to begin with -- maybe "Historical Variance in Earth's Magnetic Field Strength Measured Using Iron Age Pottery" or something.
And you know that the pottery wasn't moved from its original orientation during cooling because .... ?
Put my fist through my alarm clock with its ding-dong death inside my ear. - The Blackjacks.
Let's be clear - I didn't blame it on the scientists.
I simply said that this is an example of "why people are taking scientists less seriously".
I totally agree it's science writing; part of it may be endemic to the democritization of information in the internet age. Formerly, these sorts of fascinating, cutting edge science information would be confined to the pages of discipline-specific journals (who were well able to cover it). If something was really big news, it might show up in the NYT or on the wire, to be parsed and conveyed to other publications by a few credible, experienced 'science' writers.
Now, there's a gajilliion science magazines out there (in print and web form) so there's no possible way that they can all have competent journalists. Further, the news outraces the discipline and shows up on everything from Gizmodo to Slashdot, at BEST getting a half-assed summary from someone who spent 2 mins speed-reading the exec summary of the (as you experienced) paywalled ACTUAL paper.
-Styopa
"Christ" is a title (meaning messiah), not a name. AD is similar in that "D" stands for Domini (Latin for Lord). So both BC and AD express a Christian belief about Jesus.
BCE/CE has been a standard in discussing historical time periods for a while now. There's nothing impolite about it, just as there's nothing impolite about using Before Christ/Anno Domini, or using a Hebrew calendar, or using a Chinese calendar, or using an Islamic calendar, or a Hindu one, etc.
Possibly because it might be a little too hot to move...what would be the purpose of moving pottery before it cools?...well I guess the could have made a kiln on a wagon...or...a spinning kiln...hmmm...
Yup, much better to assume the researchers are dumber than some armchair Slashdot experts.
It's not like this is a new thing. And it really doesn't matter in ordinary conversation, at least for most of us. But when publishing in the Proceedings of the National Academy of Science, it makes sense to use the terminology of science, which does not recognize Jesus as "Christ" with all of the associated baggage.
[1] http://www.todayifoundout.com/...
https://upload.wikimedia.org/w...
So what you're saying is that there haven't been radical near-instant (in geological terms) 'spikes' of warmth about every 120k for the last 3+ million years?
Funny, that's pretty much what that graph shows to me.
-Styopa
...nightmare...
church of the better resurrection... https://betterresurrectionchurch.wordpress.com/
In america! :)
Not in the rest of the world.
It makes no sense to give a certain point in time a different name depending if you refer to it 'before' or 'after'.
Evereyone, except americans, is saying before _christ_ and after _christ_.
That means we say AD or AC and BC. The american nomenclature is just confusing
Cost free eBook I read (by iBook/Kobo/Amazon/ObookO/Gutenberg etc.): "The Green Odyssey" by Philip Jose Farmer.
"near instant (in geological terms)" means timescales of 1000 years. Not 50. That graph gives resolution of 64 years per pixel at the smallest scale, and even then as NGRIP record might point large changes on 200 years time scale, EPICA follow a much milder change.
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So the supposition is that kilns have been found with pots inside, we can demonstrate that the pots have been left undisturbed since the start of their last firing many thousands of years ago so you can judge the orientation of the earth's field at the time of cooling, and, moreover, we know the kilns haven't been moved either?
Color me skeptical.
Note that the article talks about intensity not orientation. Intensity, I understand. Orientation seems implausible with this method.
Put my fist through my alarm clock with its ding-dong death inside my ear. - The Blackjacks.
I always find it fascinating when modern science and ancient history collide. There have been a number of stories like this over the years as technology advances. It hits me in both my science and technology spot as well as being a fan of ancient history and trying to piece together things from so long ago.
That said when I read it I some how saw some bearded ancient historian crying in the corner as scientists take irreplaceable artifacts of the past, smash them, and grind up the remains for magnetic analysis. I don't *know* how they actually did it, but that's the image in my head.... :)
There's a lot of people in the rest of the world who don't care about anyone named Jesus or Christ, but who have adopted our calendar because it's in very widespread use (the network effect).
Besides, if Jesus existed, he was born a few (we don't know how many) years BC, which makes no sense. We know when the commonly used calendar started We just go with it.
"When you have eliminated the unacceptable, whatever is left, however improbable, must be the truthiness" - Holmes
Doesn't change the fact that everyone says AC and BC. ... but perhaps you are one of the few non 'english historians' who uses out of political correctness or SJW syndrome 'CE'. /. ... rofl.
I really doubt you (yes, you as a person) say in real life CE
On the other hand I got already flamed for using the term BC on
Regarding your argument about Christus, well, I would really wonder if he has not lived. But using his 'narrowed' down time of birth for a new calendar and then calling it 'common era' ... erm, I really wonder what the bigger insult is to non Christians. The fact that you use his birth as starting date or that you call that date 'common'?
Most countries that have a different calendar btw. have no problem using their own and the 'internet calender' and probably a thrd one as in reign of the King or Emporer simultaniously.
Cost free eBook I read (by iBook/Kobo/Amazon/ObookO/Gutenberg etc.): "The Green Odyssey" by Philip Jose Farmer.
It's on PNAS Early - Sci-hub.io should be fine with it.
Birds are not dinosaur descendants;birds are dinosaurs, for all useful meanings of "birds", "are" and "dinosaurs"
Before then, the kiln was built around the charge of forms using basically the same clay as the forms, the fire started in the integrated hearth (chimney also integrated to draw the fire), and the charge fired up over several days before the fire was put out and the kiln allowed to cool to the point it could be torn down to unload. Posh kilns with a lot of clay supply might make a hearth and kiln floor of fire brick for re-use, but generally it was as efficient a system as building a space ship then throwing it into the ocean after using it once.
Birds are not dinosaur descendants;birds are dinosaurs, for all useful meanings of "birds", "are" and "dinosaurs"
Hanging a dating system off on specific person's birth date has certain problems for historical work, in particular, some historical facts are needed about this person (call him Cleese, and we can all perform the Parrot Sketch before shuffling off) - such as the day of year that Cleese was born on (not in any of the manuals - indications of winter, maybe around the winter solstice?) ; also the year would be a good idea (from 1952 to 1957 BP, as defined above, even according to people who accept the next point) ; and finally, it would be a good idea to be confident that this Cleese person actually existed.
To get around these multiple problems of historical detail, the Common Era is set up to align with the astronomical measures with 0 CE being 4713 years after the last time that the Solar, Metonic and indiction cycles of eclipses and the Moon combined. Simple.
Birds are not dinosaur descendants;birds are dinosaurs, for all useful meanings of "birds", "are" and "dinosaurs"
This is flat out untrue. It could only be true if you spoke to no-one in your "real life" experience who had any background or interest in one of the historical sciences. It's possible that you have such a benighted existence, but I hope you have a more varied life than you imply.
I do say CE / BCE in real life. Whenever we're talking about historical matters at the pub - e.g. with the digger-driver with his collection of locally found stone tools. Or when talking about the several Neolithic to possibly Iron Age burial structures in the area.
Why would you not use the correct terminology? The one thing we can be sure about is that the arrow-knappers and burial-makers were not Cleesian due to this being centuries to millennia before the claimed life of Cleese
Birds are not dinosaur descendants;birds are dinosaurs, for all useful meanings of "birds", "are" and "dinosaurs"
I would suggest to simply read stuff about historical events ..
Everyone is saying BC if it is before 0 and AC if it is after, in rarer cases AD.
It is only americans and hyper critical /. readers that use CE and BCE.
I'm 50 and had english in schools. This CE and BCE stuff occured in my life a few years ago. Before that everyone understood what BC is ...
Cost free eBook I read (by iBook/Kobo/Amazon/ObookO/Gutenberg etc.): "The Green Odyssey" by Philip Jose Farmer.
Erm, what point do you want to make?
Again: except for history freaks! no one is using those terms. And then again: it is only americans, probably on a 'social justice political correctness' trip.
Just read wikipedia about random events in history, people as in actual people say BC and AC (not AD as most people are not christians or simply don't remember that english/americsns prefer AD over AC)
In other words: it might be correct english to say BCE, but 90% of the english speakers on the planet don't speak 'correct english'. They use their own words. I'm german, e.g. And no one says in german 'before common aera' so every german will simply say 'before christ' as that is how it is called in german, or italian, or spanish or chinese.
Cost free eBook I read (by iBook/Kobo/Amazon/ObookO/Gutenberg etc.): "The Green Odyssey" by Philip Jose Farmer.