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Researchers Spot Fake Ancient Pottery Using the Earth's Magnetic Field

82 points by cisc 11d ago

flimflamm 7d ago
What prevents forgers from generating such magnetic fields? That might be worth while if people start to blindly believing that "pottery frozen magnetic fields are not possible to counterfeit". Note that "not possible to counterfeit" is not a claim in the article.
- po1nt 7d ago
  I would love to see such counterfeiting. The gear they would need to get and the scientists.
  - awesomeusername 7d ago
    Some wire and DC? and Claude et al
- adrian_b 7d ago
  From TFA: > “So it’s hard for us to be ahead of the forgers since they can read our papers and figure out ways to trick our methods.”
- Cthulhu_ 7d ago
  It's one of several techniques they can apply, at least. I for one don't even know why there's a forgery market for ancient pottery, or that there's a market for it.
  - p-e-w 7d ago
    > I for one don't even know why there's a forgery market for ancient pottery Because people desire owning ancient pottery and are therefore willing to pay for it.
    - charlieyu1 7d ago
      Forgery is so ancient that we have forgery ancient items made in ancient times
  - mschuster91 7d ago
    > I for one don't even know why there's a forgery market for ancient pottery People have paid top dollar for archeological artifacts for centuries. Humanity lost a lot of knowledge from graverobbers, illegal artifact hunting and unreported thefts of stuff getting exposed after stuff like forest fires.
    - fn-mote 7d ago
      > Humanity lost a lot of knowledge from graverobbers […] Don’t forget the major scale destruction wrought by wars (religious and otherwise) - eg in the Middle East. You might also want to count cultural theft. (Where are the gates of Babylon now??)
- bell-cot 7d ago
  > What prevents forgers from ... Cost. Same as them fooling carbon dating, electron microscopes, isotope analysis, and a host of other techniques. Forgery has always been about how cheaply you could make fakes, vs. the odds and consequences of them getting enough scrutiny to be identified as such.
  - brookst 7d ago
    It’s the banknote thing: at some point a great forgery costs more than the real thing.
mayneack 7d ago
The method of seems to involve hearing the artifacts which seems plausibly risky for an ancient artifact.
profsummergig 7d ago
can this clue be circumvented by using magnets oriented in a certain way around the workshop while constructing the pottery?
- comrade1234 7d ago
  There are two fields. The second very weak field is acquired over centuries, I assume when the piece is not moved. The primary stronger field is created when it's first formed. I think what you're talking about would orientate the primary field, not the weak field.
  - skew-aberration 7d ago
    The second field can probably be created by changing the first field while the piece is still cooling down.
thangalin 7d ago
https://impacts.to/downloads/lowres/impacts.pdf#page=23 https://impacts.to/downloads/lowres/impacts.pdf#page=23 Quoting my book: "Studying these layered strata is known as magnetostratigraphy and can be used to verify radioactive dating methods. Geologists used magnetostratigraphy to cross-check the dates of the Nakali Formation, where Nakalipithecus nakayamai’s jaw was found."
userbinator 7d ago
Because the location of the pole is constantly shifting, the TRM of ancient pottery points in a slightly different direction than that of pottery made today. Did anyone else have a strong "WTF?" reaction upon reading that sentence? Yes, the pole has moved. No, it's completely irrelevant given that not every piece of pottery even manufactured at the same time is going to be fired in the exact same orientation relative to the pole. The researchers determined that any sample older than a millennium had to be heated to at least 234 degrees Fahrenheit before its VRM was erased. New pottery samples’ VRMs, meanwhile, could be wiped at lower temperatures. That's a more useful difference which I would attribute to the ceramics having different Curie points in their compositions, and of course it's not something too difficult to change: https://en.wikipedia.org/wiki/Curie_temperature#Changing_a_material's_Curie_temperature https://en.wikipedia.org/wiki/Curie_temperature#Changing_a_m... Incidentally, this effect of temperature on magnetism is how the https://en.wikipedia.org/wiki/Magneto-optical_drive https://en.wikipedia.org/wiki/Magneto-optical_drive media records data.
- MadnessASAP 7d ago
  We should probably assume that the authors are aware of ceramics, Curie points, and the earth magnetic field. While the article isn't very clear on what effect causes the change in temperature needed to erase the VRM. I suspect is has something to do with how long the object has spent stationary with respect to the earth's field. At least that's my takeaway from having to periodically rotate magnetometers to prevent them from acquiring a bias.
  - Gibbon1 7d ago
    I'm reminded of thermoluminescence for dating objects. Radiation creates defects in the material over time. When heated the defects release light. Imprecise but will fink on ceramics that were fired 30 years ago vs 3000 years ago. Difficulty you need to heat a fair sized sample. "Reads article" Impression, author didn't understand any of what he was told. But yes similar, over time the object picks up a faint magnetic field superimposed on the one locked in when the ceramic was made.
- adrian_b 7d ago
huurtehoog 7d ago
I find it infinitely fascinating that everything that ever happens leaves a trail of information that we keep getting better at querying. From understanding what exactly stars are made of, to the evolution of life on Earth, and the exploits of humans living thousands of years ago. It's really uncanny the unreasonable effectiveness of mathematics, something we made up by manipulating abstract symbols, in modelling and helping us understand the universe in every minute detail we care to inquire. Truly miraculous.
- pif 7d ago
  Mathematics is a tool. What make such understanding possible are the relentless, disciplined, often-pointless-looking collection and categorization of data of any kind, by generations and generations of selfless scientists.
- Lord-Jobo 7d ago
  Inherent principles exist in any really high resolution system that are so hard to control they can usually be tracked and manipulated but never completely controlled. It’s why cancer is so prevalent and damn near unsolvable: an organism our size has about 7 octillion atoms, even forgetting the impacts of the stuff smaller than that. That’s 30ish trillion cells, many are multipurpose little motor vehicles inside our body running around doing stuff constantly. It’s just so much STUFF happening, take the brain out of someone and leave them a vegetable digesting on a bed and they still burn hundreds of kcal a day, and that’s a highly efficient system millions of years in production. So two things emerge from that, 1: extremely robust universal principles like electromagnetic gradients being used for travel, and 2: runaway feedback loops like black holes or cancerous cells. What that means is that you can view mathematics as a spontaneous emergence FROM a high resolution system, or the inverse. We usually think of the inverse, because it seems like no matter what we discover in the system it can be explained by increasingly complex math. But the inverse of that is very interesting to me: math emerges as a side effect from the high resolution system. It also passes the smell test, if you make a low resolution simulation of the solar system you will not see the effects of the high complexity systems, relativity works perfectly without any quantum dynamics. I just love these kinds of chicken and egg problems.
amelius 7d ago
Reminds me of this: https://boards.straightdope.com/t/sound-recordings-on-ancient-pottery/225466/2 https://boards.straightdope.com/t/sound-recordings-on-ancien... (sound recordings in clay)
rietta 7d ago
Fascinating! I wonder if cloth artifacts, such as the Shroud of Turin, would also exhibit similar signatures. Though I have read some extremely compelling multi-disciplinary evidence exist to its authenticity to 1st century Judea, not a forgery.

82 points by cisc 11d ago

What prevents forgers from generating such magnetic fields? That might be worth while if people start to blindly believing that "pottery frozen magnetic fields are not possible to counterfeit". Note that "not possible to counterfeit" is not a claim in the article.

po1nt 7d ago
I would love to see such counterfeiting. The gear they would need to get and the scientists.
- awesomeusername 7d ago
  Some wire and DC? and Claude et al
adrian_b 7d ago
From TFA: > “So it’s hard for us to be ahead of the forgers since they can read our papers and figure out ways to trick our methods.”
Cthulhu_ 7d ago
It's one of several techniques they can apply, at least. I for one don't even know why there's a forgery market for ancient pottery, or that there's a market for it.
- p-e-w 7d ago
  > I for one don't even know why there's a forgery market for ancient pottery Because people desire owning ancient pottery and are therefore willing to pay for it.
  - charlieyu1 7d ago
    Forgery is so ancient that we have forgery ancient items made in ancient times
- mschuster91 7d ago
  > I for one don't even know why there's a forgery market for ancient pottery People have paid top dollar for archeological artifacts for centuries. Humanity lost a lot of knowledge from graverobbers, illegal artifact hunting and unreported thefts of stuff getting exposed after stuff like forest fires.
  - fn-mote 7d ago
    > Humanity lost a lot of knowledge from graverobbers […] Don’t forget the major scale destruction wrought by wars (religious and otherwise) - eg in the Middle East. You might also want to count cultural theft. (Where are the gates of Babylon now??)
bell-cot 7d ago
> What prevents forgers from ... Cost. Same as them fooling carbon dating, electron microscopes, isotope analysis, and a host of other techniques. Forgery has always been about how cheaply you could make fakes, vs. the odds and consequences of them getting enough scrutiny to be identified as such.
- brookst 7d ago
  It’s the banknote thing: at some point a great forgery costs more than the real thing.

mayneack 7d ago

The method of seems to involve hearing the artifacts which seems plausibly risky for an ancient artifact.

profsummergig 7d ago

can this clue be circumvented by using magnets oriented in a certain way around the workshop while constructing the pottery?

comrade1234 7d ago
There are two fields. The second very weak field is acquired over centuries, I assume when the piece is not moved. The primary stronger field is created when it's first formed. I think what you're talking about would orientate the primary field, not the weak field.
- skew-aberration 7d ago
  The second field can probably be created by changing the first field while the piece is still cooling down.

thangalin 7d ago

https://impacts.to/downloads/lowres/impacts.pdf#page=23 https://impacts.to/downloads/lowres/impacts.pdf#page=23 Quoting my book: "Studying these layered strata is known as magnetostratigraphy and can be used to verify radioactive dating methods. Geologists used magnetostratigraphy to cross-check the dates of the Nakali Formation, where Nakalipithecus nakayamai’s jaw was found."

userbinator 7d ago

Because the location of the pole is constantly shifting, the TRM of ancient pottery points in a slightly different direction than that of pottery made today. Did anyone else have a strong "WTF?" reaction upon reading that sentence? Yes, the pole has moved. No, it's completely irrelevant given that not every piece of pottery even manufactured at the same time is going to be fired in the exact same orientation relative to the pole. The researchers determined that any sample older than a millennium had to be heated to at least 234 degrees Fahrenheit before its VRM was erased. New pottery samples’ VRMs, meanwhile, could be wiped at lower temperatures. That's a more useful difference which I would attribute to the ceramics having different Curie points in their compositions, and of course it's not something too difficult to change: https://en.wikipedia.org/wiki/Curie_temperature#Changing_a_material's_Curie_temperature https://en.wikipedia.org/wiki/Curie_temperature#Changing_a_m... Incidentally, this effect of temperature on magnetism is how the https://en.wikipedia.org/wiki/Magneto-optical_drive https://en.wikipedia.org/wiki/Magneto-optical_drive media records data.

MadnessASAP 7d ago
We should probably assume that the authors are aware of ceramics, Curie points, and the earth magnetic field. While the article isn't very clear on what effect causes the change in temperature needed to erase the VRM. I suspect is has something to do with how long the object has spent stationary with respect to the earth's field. At least that's my takeaway from having to periodically rotate magnetometers to prevent them from acquiring a bias.
- Gibbon1 7d ago
  I'm reminded of thermoluminescence for dating objects. Radiation creates defects in the material over time. When heated the defects release light. Imprecise but will fink on ceramics that were fired 30 years ago vs 3000 years ago. Difficulty you need to heat a fair sized sample. "Reads article" Impression, author didn't understand any of what he was told. But yes similar, over time the object picks up a faint magnetic field superimposed on the one locked in when the ceramic was made.
adrian_b 7d ago

huurtehoog 7d ago

I find it infinitely fascinating that everything that ever happens leaves a trail of information that we keep getting better at querying. From understanding what exactly stars are made of, to the evolution of life on Earth, and the exploits of humans living thousands of years ago. It's really uncanny the unreasonable effectiveness of mathematics, something we made up by manipulating abstract symbols, in modelling and helping us understand the universe in every minute detail we care to inquire. Truly miraculous.

pif 7d ago
Mathematics is a tool. What make such understanding possible are the relentless, disciplined, often-pointless-looking collection and categorization of data of any kind, by generations and generations of selfless scientists.
Lord-Jobo 7d ago
Inherent principles exist in any really high resolution system that are so hard to control they can usually be tracked and manipulated but never completely controlled. It’s why cancer is so prevalent and damn near unsolvable: an organism our size has about 7 octillion atoms, even forgetting the impacts of the stuff smaller than that. That’s 30ish trillion cells, many are multipurpose little motor vehicles inside our body running around doing stuff constantly. It’s just so much STUFF happening, take the brain out of someone and leave them a vegetable digesting on a bed and they still burn hundreds of kcal a day, and that’s a highly efficient system millions of years in production. So two things emerge from that, 1: extremely robust universal principles like electromagnetic gradients being used for travel, and 2: runaway feedback loops like black holes or cancerous cells. What that means is that you can view mathematics as a spontaneous emergence FROM a high resolution system, or the inverse. We usually think of the inverse, because it seems like no matter what we discover in the system it can be explained by increasingly complex math. But the inverse of that is very interesting to me: math emerges as a side effect from the high resolution system. It also passes the smell test, if you make a low resolution simulation of the solar system you will not see the effects of the high complexity systems, relativity works perfectly without any quantum dynamics. I just love these kinds of chicken and egg problems.

amelius 7d ago

Reminds me of this: https://boards.straightdope.com/t/sound-recordings-on-ancient-pottery/225466/2 https://boards.straightdope.com/t/sound-recordings-on-ancien... (sound recordings in clay)

rietta 7d ago

Fascinating! I wonder if cloth artifacts, such as the Shroud of Turin, would also exhibit similar signatures. Though I have read some extremely compelling multi-disciplinary evidence exist to its authenticity to 1st century Judea, not a forgery.