Carbon Dating, easy to be wrong?

Hello everyone,

I just read an article that had talked about carbon dating an ancient religious book. Apparently they were able to date the book by carbon dating the paper. I just don’t get it. What if the material used to make the paper had been sitting in a barn for 500 years? I realize that testing of this nature can narrow down the age of something, but it seems to me that this could have everything or nothing to do with how old a particular object is, just the carbon based components of the object. These carbon based components could have been around long before the object itself.

How does carbon dating work and is it really the best indicator of age?

Well, wouldn’t it help to at least get the maximum age possible of an artifact to be dated; if the paper is found to be only 800 years old, yet the claim was that the book is from 800CE, then clearly that claim is false.

Isn’t that one of the objections made after they tested the shroud of Turin, and found it could not have dated from the time of Christ?

I think the key is to remember what you’re testing. Scientists don’t usually forget that, but the media usually does. If a scientist tests the paper, then his results will read something like “The tree that made this paper ceased growing x +/- y years ago.” He won’t make any comment on the age of the book based on carbon dating - as you point out, the tree or paper might have sat around for quite some time before being made into a book.

And even then, a book that is in regular use has new carbon being added when people touch it and when bacteria or mold grows on it. So it might be totally unsuited for carbon dating as a technique.

I remember some discussion in school where an archaeological site was being dated and someone in the class thought we should be able to date their stone tools. That would be pointless because it would only show the age of the rock, not when it was made into a tool.

As a final note, because of the relatively short half-life for carbon, it’s not useful for ages past 50,000 years or so.

So… I would argue that carbon dating is never the “best” way to date something, especially something man-made. It’s just one more way to get an additional data point that can help narrow down the other available options.

You raise a worthwhile issue, and people have addressed the appropriate error bars around the date determination. But … can I trouble you to think critically about your specific objection? Someone manufactures paper, stores it for 500 years, then someone finds it and makes a document from it? A document of some importance? Where, in our world, with warehouses, and storage facilities and the like, can you find 500 year old consumables, like paper? Can you extrapolate that unlikely coincidence, to Ancient times to come up with something that isn’t even more likely? An ancient book would likely be made of parchment, prepared sheepskin, and hand written. Would someone make a sheepskin, and ignore it for 500 years, and then start writing on it? Were there stacks of prepared sheepskins in the monastery’s local Kinko’s outlet, and some just got misplaced in the illuminated ink bin?

Yes. Parchment was expensive.

(Link is to a 9th century Monk-scribe who erased and re-used a 5th century Greek parchment)

Actually, I believe you can’t carbon date the rock at all. In order to carbon date an item, it has to have carbon in it, which usually means organic material. What can be done it to date organic material from near a stone tool. So if you find a stone arrowhead next to the remains of a firepit that contains charcoal bits, you can date the charcoal, and make assumptions about the arrowhead being used at the same time the firepit was.

Actually, it’s not completely unknown to find loose blank sheets of paper among bundles of documents in archives. Also, bound volumes, whether of paper or parchment, often contain blank folios, so a standard technique for forgers is to cut out such pages. One famous example where that may (or may not) have been done would be the Vinland Map.

But, as dracoi has already pointed out above, it’s not as if those who do the testing aren’t fully aware of this potential problem. But, then again, no thorough investigation of an object ever depends only on a single type of evidence.

You’ll see a lot of criticism of carbon dating on the internet, mostly from creationists. It’s important to understand that carbon dating, like all scientific assays, has limits. If the test is used inappropriately, like on samples that don’t have carbon for instance, then it’s going to give you ridiculously, wildly wrong results. It’s this type of result that critics love to parade on poorly-written websites. However, what is nearly always ignored by these people is that scientists understand these limits perfectly well. Hell, it was scientists that figured the limits out in the first place. So a real, reputable scientist is going to take those limits into account when he or she does their test. If for some reason they fail to do that, they’ll get called on it approximately three seconds after publishing, assuming none of the peer reviewers catch it, which is highly unlikely. And yet, we still have this litany of laypeople yammering on about how “oh, this one time some guy did this thing and found that my lunch was ten thousand years old, hurr hurr hurr.” It irritates me.

I’m not saying the OP is in this camp - just that this is something I see a lot when people start talking about carbon dating. Tangent over. Carry on.

Just to nitpick, though I could be wrong, I believe there is away to date at least Obsidian tools, based on a moisture level on the outer layers of the stone. Which is a really simple explanation that may not be totally correct.

Yes, a standard forgery trick to get appropriately aged paper was to cut the frontspieces out of old books. The next trick was to get appropriately aged and formulated ink.

Objections to the shroud of Turin carbon dating included suggestions (anything but admit the obvious) that newer peices ahd been woven in to repair it (not the triangles sewn in to repair the burns). Also pollen from more recent times embedded in it; carbon from the more recent fire that may have wafted or washed ito it.

Similarly, the quesion about a human campsite in South America, dating 10,000 years earlier than humans are believed to have arrived in the Americas - was it debris from earlier organic deposits mixed into the firepit ashes?

I guess to clarify after I have given the matter done additional thought, the paper can be dated by the carbon decay of the tree the paper was made from. The tree could have been dead for a thousand years prior to being made into paper. I don’t know how they make paper, but I guess a dead tree can be used. Same with the Shroud of Turin. I am going to assume it’s made from a cotton type material. The cotton could have been picked, weaved and sat around as cloth for a long time prior to being used.

I am not knocking carbon dating, but I can’t see putting much faith in using it to date man made objects, there is way to much room for error. I have hears some of the most desirable wood is that from the bottom of done frigid lake (I can’t recall the name of the lake). The TV show I saw it on claimed the wood was thousands of years old. If one wee to Gertrude some of that and make a fine commence table from it and it was discovered 5000 years from now the carbon date would show it being made earlier than today. Just got me thinking ass it seems so many take carbon dating at face value.

The carbon date would not show it being made earlier than today. The carbon date would not show anything at all about when it was made. It’s a totally inappropriate technique for determining the date of manufacture.

Carbon dating can - at best - do no more than determine when the tree ceased living.

But you don’t need to take it blindly at face value to find it useful. I mean, the year 7000 AD archeologists wouldn’t just carbon date your table and stop. They’d look carefully at the table and see that it was machine sawn, so certainly from after about 1800 or so. They’d look at the finish, maybe notice that the color is synthetic, therefore mid-1800s or later. They’d look at the curve and see a strong Art Deco look, which is more subjective, but strongly suggestive of being made 1920s or later. They might find a screw made out of a metal allow that was only generally used after 1970 or so. And they might, say, notice that it’s far too big and chunky to have been made after the Wood Conservation Laws of 2047. So, they’d conclude that the table was made sometime in the late 20th/early 21st century, long after the tree died. And that would be interesting – it would show that by the time the table was made, very large trees were becoming so scarce that people would go pull ancient logs out of lakes just to make furniture out of.

Contrariwise, if the table was thought to be possibly 10,000 years old, but the carbon dating showed the tree died only 200 years ago, that’s pretty strong evidence that the table isn’t that old.

PS-- And, I hope this isn’t raining on your parade, but I think what you might have heard about as far as sunken logs go, is more like 200 year old logs, that sunk in rivers in New England as they were being floated downstream to sawmills. There’s nothing special about the wood itself; the only good thing about the logs is the width of the tree and therefore the width of the boards you can get. They’re valuable mostly to people trying to authentically restore old houses with very wide boards, since there aren’t many very big trees to make wide boards from anymore.

Thanks for the clarification. I could only vaguely recall the show about the sunken logs. I clearly remembered them being extremely desirable and valuable, but I couldn’t recall if it was because of the type of wood, the fact that being submerged for so long changed the character of the wood or as you stated, the width.

As a whole though I have to say that once again my inquiry has been answered. It seems as if carbon dating of a man made artifact is more useful in ruling out an item rather than verifying its authenticity. If an object was claimed to be five thousand years old, but can be shown through carbon dating to only be a thousand years it rules out the possibility. It hasn’t advanced to the point of being useful for determining a made on date. Thanks for the replies!

P.M. I apologize for the glaring grammatical edit in my second post. Seems that my Android’s auto-correct has stabbed me in the back again. I am getting much better at proof reading prior to hitting the submit button, but every so often I neglect to check. My thanks to all of you for not going all "Grammar Nazi"on me! :smack: