Carbon-14 DatingApril 18, 2007
Carbon-14 Dating, or just Carbon Dating, is an extremely useful dating method that’s been in use since 1947. Carbon Dating is part of a larger field called Radioisotope dating which is our primary method for assigning date to fossils, rocks, skeletons, and parchment. “Before the 1940s, scientists had no accurate way of determining the age of fossils or other ancient objects” notes Lemelson-MIT. Radioisotope dating is, to my knowledge, basically the only way that we date fossils, rock layers, and by extension the age of the Earth. Since it is so crucial we’ve gotten very good at it. We have advanced machines with amazing levels of accuracy and procedures to avoid any contamination. So let me explain how carbon dating works and then we’ll get on to some interesting stuff.
Carbon-14 is a radioactive isotope of regular old carbon. From what we know, carbon-14 is created in the upper atmosphere by solar radiation colliding with nitrogen to produce carbon-14. It then drifts down through the atmosphere and is absorbed by plants, which are eaten by herbivores, then carnivores, and it enters the cycle of life. Living things sustain a present day level of about 1 carbon-14 atom in 1 trillion atoms. When something dies, it stops taking in carbon-14 by breathing and eating, so the clock begins. Carbon dating allows us to track the time of death with great accuracy because it has a very short half-life. Half the amount of carbon is depleted every 5,730 years. This means that for a finite 1 gram sample there will be absolutely no carbon-14 left in the sample after around 230,000 years. So these are the base assumptions for all radioisotope dating (remember axioms?):
- Original Amounts known (present day values used)
- Rate of decay must be constant (present day measurements used)
- Closed System assumption (rocks should not cross-contaminate)
As I mentioned, we’ve gotten really good at this radioisotope dating thing and so scientists have developed “Isochron Plots” to test assumptions 1 and 3. Rate of decay isn’t really double-checked but it is based on the basic atomic structure of the atom. So now you know more about radioisotopes than 99% of the world.
Here’s the interesting part: when scientists go out and sample every fossil, rock, peice of coal, marble, wood, or any fossil they find low levels of Carbon-14 in them. Now remember, anything past 250,000 years (or earlier) should be totally carbon dead if the assumptions hold. This was originally attributed to limited machine accuracy. But machine accuracy has improved, in fact, scientists have known about this problem for over 20 years. The obvious conclusion was that something they were doing was contaminating the samples (assumption 3). So they scour the lab, set up the most strict procedures. Before doing a test they dunk a sample in acid, then base, then acid again to remove any outside contamination. What they found is that the carbon levels remained. Eventually, people working at the carbon dating labs concluded that the samples must be contaminated out in the field, before it ever got to the lab, and dropped the issue. Carbon dating is only used for things considered recent for this reason.
It took a group of very unorthodox scientists called the RATE team to look at it again. This is why I like people who go against the grain. They came up with the idea of testing the contamination assumption by carbon dating diamonds. Diamonds are the perfect choice; they are the hardest substance in the world, they’re made from carbon, they can’t be infiltrated by water, and they’re assumed to be ancient, dating back to the origins of life on this planet. They collected multiple diamonds from multiple layers in different mines all around the world and selected the world’s premier carbon dating labs to have them tested. No one had bothered testing diamonds because they are very hard to test and should be entirely carbon-dead. What they found is that diamonds have a similar range of carbon-14 as most fossils do. If you use uniformitarian assumptions we can calculate the age to approximately 58,000 years old. That’s a big difference from the expected 1-2 billion years. (poster)
There’s four definite possibilities that I can see from this data. One or more of the 3 base assumptions are wrong or if all assumptions hold, diamonds are really 58,000 years old. Interestingly, no one is claiming that all diamonds are 58,000 years old because it doesn’t fit with anyone’s model quite right. At the very least, this data should call into question the unswerving accuracy of radioisotope dating methods. Being off by a factor of 1,000 is not acceptable in most academic circles.
(I’ll be getting back to this topic in a later article.)
Further Comments: I had a friend bring up the issue of statistical outliers. These are common occurrences of things that do not agree with the general trend. Most of the time these outliers are thrown out as errors. He pointed out that if you threw out the main body and instead kept any outliers that agreed with you then you could make the data say whatever you wanted. First off, people are dumb but I’d think that even a very biased person would notice throwing out MOST of the data that they personally generate. So this is essentially based on the conviction that these people are being dishonest.
That aside, I asked Dr. Baumgardner (primary researcher) about this directly. He said that there actually WERE some outliers in the data that he threw out because he felt they were errors. Well I guess we caught them. Except for, the samples (a minority) he threw out actually showed younger dates than the rest of the group. So he’s actually showing the oldest dated samples. The samples that were thrown out dated to closer to 11,000 years, which would be much easier to reconcile with a young earth model. This batch used a different cleaning process which he believed was suspect because one of the ingredients contained carbon. Instead he kept the ones that, while presenting trouble for an old earth, also didn’t fit perfectly with his model.
I think the main criticism that can be leveled at this point is that they haven’t tested ALL the diamonds in the world, so you can’t prove a non-existence. The diamonds they did test were from all over the world and different beds and elevations, even some from alluvial deposits. I’ve heard other researchers have confirmed these results but I went looking and couldn’t find anything else. Usually private companies, like carbon dating labs, don’t publish papers in journals, it’s not their primary motivation. And to anyone who would like to make up a story about how diamonds are a special case and how C-14 dating still works on everything else, remember this was made to test why all fossils have relatively young C-14 dates.