How does radiocarbon dating actually work?

[sjastro]

In my last post I gave an example of Rb-Sr isochron dating and given the dishonesty of creationist organizations such as AIG and CARM (Christian Apologetics and Research Ministry) about radiometric dating, the following video debunks their claim Rb-Sr isochron dating is broken.

 

[linux.poet]

Almost 2 billion years ago, uranium was so concentrated in one area that there was some slight additional radioactive fission. A natural nuclear reactor, due to naturally 'enriched' uranium. Analyzing the daughter nuclei present in samples allows us to conclude that the radioactivity processes are constant over that time span within pretty strict limits.

For 'young earth' scenarios where we tinker with decay rates in order to collapse billions of years into thousands of years, the release of that much nuclear energy in that short a time would vaporize the earth.

(This post was linked earlier.) I'm now wondering what the process is to determine these radioactive half-lives for these isotopes. How do the scientists know that it takes 4.5 x 10^9 years for uranium to decay into lead, for example?

goes step by step through the U-Pb Zircon Geochronology process to date rocks. This process is used only to date rocks, mainly of the igneous and metamorphic kind.

That video was helpful, but I'm now wondering about the reliability of this source, whether it is correct or not:

This seems to address a lot of points that make the other data placed in this topic go "aha" and make more sense. It came up in the recommended section when I was watching your video.

 

[dlamberth]

That video was helpful, but I'm now wondering about the reliability of this source, whether it is correct or not:

Geologist are also concerned about the source. Their want is to do it right. So they are very careful where they harvest from. They also take, if they can, take multiple samples to the lab.

In another area of geoscience work in the lab for instance, has to do with determining how deep the source in the earth a lava flow came from. Or where it came from, which can tell us a lot. So it's not all about finding the age of rocks. There are other area's of geology where samples are ran through a lab for one reason or another. Lab work has become an important tool for the geologist.

 

[NxNW]

(This post was linked earlier.) I'm now wondering what the process is to determine these radioactive half-lives for these isotopes. How do the scientists know that it takes 4.5 x 10^9 years for uranium to decay into lead, for example?

The decay rate is easily measured, and the age of a sample can be extrapolated with college freshman level calculus. There is very strong evidence that the decay rates do not change.

 

[linux.poet]

The decay rate is easily measured, and the age of a sample can be extrapolated with college freshman level calculus.

I only passed calculus I, after 4 attempts.

 

[Job 33:6]

(This post was linked earlier.) I'm now wondering what the process is to determine these radioactive half-lives for these isotopes. How do the scientists know that it takes 4.5 x 10^9 years for uranium to decay into lead, for example?

There are a handful of different ways that this is done. But one of which, is with use of machines that basically just have sensors on them that count the rate that particles are emitted as the element decay.

Radioactive elements emit particles that can be detected and counted with sensors.

Similar to how you can have radon checked in your basement. You take your sample and you put it in a sealed chamber with sensors around it that detect emitted particles.

So you have a means of direct measurement of rates of decay with instruments that directly measure decay, much like Geiger counters.

 

[essentialsaltes]

(This post was linked earlier.) I'm now wondering what the process is to determine these radioactive half-lives for these isotopes. How do the scientists know that it takes 4.5 x 10^9 years for uranium to decay into lead, for example?

I'm not an experimentalist, but my theoretical take is similar to what others have said.

From ordinary chemistry of moles and masses, you can know that a sample of a particular isotope has 4.8 bajillion atoms. Then you surround your sample with a Geiger counter and find out how many clicks there are per second. This decay rate is inversely related to the half-life. The faster it clicks, the shorter the time for it to decay away.

AI:
To convert half-life to decay rate (also called decay constant), use the equation: decay rate (λ) = 0.693 / half-life (t1/2); meaning, the decay rate is calculated by dividing the natural logarithm of 2 by the half-life of the radioactive substance. [or vice versa]

 

[sjastro]

(This post was linked earlier.) I'm now wondering what the process is to determine these radioactive half-lives for these isotopes. How do the scientists know that it takes 4.5 x 10^9 years for uranium to decay into lead, for example?

Sorry for the nit-picking but the value you quoted is for half life which is the amount of time 50% of the parent nuclei has decayed.

This leads to another important consideration; half life is a statistical median which is the midpoint of an exponential distribution.

Since statistics is involved, this can involve some very counterintuitive ideas.
I'll use the example of the half life of Xenon 124 to show the half life is calculated rather than measured using both theoretical and experimental physics.

The Xenon 124 nucleus can capture 2 electrons converting two protons into two neutrons which decays to ¹²⁴Te (Tellurium 124) and two neutrinos according to the reaction

¹²⁴Xe + 2e⁻ → ¹²⁴Te + 2νₑ

The half life for the decay is an astonishing 1.8 x 10²² years which is over a trillion times older than the age of the universe.

I imagine creationists would have a field day yet the decay of ¹²⁴Xe has been observed from which the half life can be calculated.
If ¹²⁴Xe decayed within the time fame of the age of the universe, the event would sit in the left hand side of the exponential distribution where the fraction of ¹²⁴Xe remaining dominates.
To observe a decay event in the time frame of say one year would require an enormous number of ¹²⁴Xe atoms which fortunately we have in the form of liquid Xenon dark matter detectors.

Here is the mathematics behind the calculation of the half life.

82 real decay events were recorded over a period of one year for a 1000 kg mass of liquid Xe from the XENON1T dark matter detector.
Assuming a knowledge of high school chemistry the molar mass of Xe is 131.3g/mol of which the natural abundance of ¹²⁴Xe is 0.095%.
1 mole of Xe contains 6.02 x 10²³ atoms of Xe and the number of ¹²⁴Xe atoms in 1000 kg of Xe is:

(1000/1.31) x 0.00095 x 6.02 x 10²³ = 4.35 x 10²⁴ atoms of ¹²⁴Xe.

The decay constant λ = [(number of decay events)/(number of ¹²⁴Xe atoms)] x t x ε where ε is the detection efficiency factor for the XENON1T and is ≈ 0.5

For t =1 year, λ = [82/(4.35 x 10²⁴ x 0.5)] = 3.77 x 10⁻²³/year

Now using the formula for half life t₀.₅ = ln(2)/λ = 0.693/3.77 x 10⁻²³ ≈ 1.8 x 10²² years.

 

[sjastro]

The oldest half life albeit theoretical makes the half life of ¹²⁴Xe positively young by comparison.

There are various theories generically known as GUTs (Grand Unified Theories) which attempt to unify electromagnetic, weak and strong forces into a single force which would have existed in the very early history of the universe when it was extremely hot and dense.
One of the predictions of GUTs is proton decay, proton decay is only observed in atomic nuclei as β⁺ decay according to the equation:

p → n + e⁺ + νₑ where n, e⁺, νₑ is the neutron, positron and neutrino respectively.

Free protons on the other hand are extremely stable but GUTs predict:

p → e⁺ + π₀
π₀ → ϒ + ϒ where π₀ and ϒ are the neutral pion and photon respectively.

The predicted half life of the proton is beyond imagination t₀.₅ ≈ 10³⁶ years making it 72.5 quadrillion trillion times older than the age of the universe.
To put this in perspective if the age of the universe was reduced to 1 second, the proton half life would be 2.3 quintillion years. (a quintillion is a 1 followed by 18 zeros).

The Super-Kamiokande neutrino detector should also be to detect proton decay as it uses 50,000 tons of ultra pure water which is a source of ~ 10³⁴ protons.
Even then the chances of detection are extremely thin as the reaction rate λ = ln(2)/ t₀.₅ ≈ 0.693/10³⁶.
Events/year = 10³⁴ x 0.693/10³⁶ ≈ 0.007.
This means one proton decay event should occur every 140 years in the Super-Kamiokande detector which is a very poor return.

There could of course be another explanation the theory is wrong and protons do not decay.

 

[rambot]

But it’s flawed because of the flood. The upheaval was so great that it even changed the age of rocks Making them seem older.

How did water reintroduce PERFECTLY the EXACT right number of carbon14 or any one of the other isotopes back into "rocks"?

I mean, that's a convinient argument, but there are some rather gigantic claims here that are just tossed out like "well of course...."

 

[linux.poet]

How did water reintroduce PERFECTLY the EXACT right number of carbon14 or any one of the other isotopes back into "rocks"?

According to this science presented here, it would appear that a large amount of recent volcanic activity or metamorph would be required to reset the isotropic “clocks”. Water would not really do the trick.

The flood would explain the high level of sedimentary rock around the earth available to be studied, but sediment accumulation isn’t a chemical change on the atomic level as far as I know. Metamorphosis is, but sedimentation is not.

The flood also would explain why there are a bunch of dead fossils to study. From what I’m reading so far, it should be a relatively easy (I say “relatively” because the scientific test I saw was a big multi step process of chemical separation) to run a test for carbon-14 isotopes on a fossil. If the isotopes are present, it’s probably only thousands of years old, but if there are none and all the carbon-14 has decayed, then you could conclude millions of years. On the other hand, a live carbon-14 atom would mean that your fossil is only thousands of years old, or your sample is contaminated. It probably would be more robust to run a standard radiometric dating process on the rock around the fossil as well and see if that matches up.

But again, that also makes no sense. It looks like we are comparing apples and oranges, because radiometric dating is used to determine the age of igneous and metamorphic rock, not sedimentary rock. Since the sedimentation process doesn’t chemically change the atoms, radiometric dating isn’t really an effective tool to date sedimentary rock. It doesn’t tell when the sediment changed into rock, and thus other dating methods than radiometric dating would need to be used. This means that radiometric dating cannot tell you when the biblical flood happened, we are taking a wrench to a screwdriver problem.

Correct me if I’m wrong…

 

[essentialsaltes]

According to this science presented here, it would appear that a large amount of recent volcanic activity or metamorph would be required to reset the isotropic “clocks”. Water would not really do the trick.

We agree.

The flood would explain the high level of sedimentary rock around the earth available to be studied,

I would substitute 'could' for 'would', but yes. But if there were someone more versed in geology than I am, they might well say 'can't'.

but sediment accumulation isn’t a chemical change on the atomic level as far as I know.

Yes, this is important. Even moreso, the radiometric method relies on isotopes -- differences in the nucleus. So it would require not just a chemical or atomic process, but a nuclear one. This is just not possible from water or physical mixing or laying down sediments.

 

[Job 33:6]

The flood would explain the high level of sedimentary rock around the earth available to be studied,

Correct me if I’m wrong…

Just looking at @essentialsaltes, I'd consider myself well versed in geology. And he's right that most professionals would opt for the "can't" re-wording, as opposed to "the flood 'would' or 'could' explain the high level of sedimentary rock around the earth.

I'm sure 99% of geologists would agree that there are far far too many issues with "flood geology".

 

[sjastro]

That video was helpful, but I'm now wondering about the reliability of this source, whether it is correct or not:

This seems to address a lot of points that make the other data placed in this topic go "aha" and make more sense. It came up in the recommended section when I was watching your video.

I had no issues with the video, her knowledge of the subject is backed up by her qualifications.

 

[Job 33:6]

According to this science presented here, it would appear that a large amount of recent volcanic activity or metamorph would be required to reset the isotropic “clocks”. Water would not really do the trick.

The flood would explain the high level of sedimentary rock around the earth available to be studied, but sediment accumulation isn’t a chemical change on the atomic level as far as I know. Metamorphosis is, but sedimentation is not.

The flood also would explain why there are a bunch of dead fossils to study. From what I’m reading so far, it should be a relatively easy (I say “relatively” because the scientific test I saw was a big multi step process of chemical separation) to run a test for carbon-14 isotopes on a fossil. If the isotopes are present, it’s probably only thousands of years old, but if there are none and all the carbon-14 has decayed, then you could conclude millions of years. On the other hand, a live carbon-14 atom would mean that your fossil is only thousands of years old, or your sample is contaminated. It probably would be more robust to run a standard radiometric dating process on the rock around the fossil as well and see if that matches up.

But again, that also makes no sense. It looks like we are comparing apples and oranges, because radiometric dating is used to determine the age of igneous and metamorphic rock, not sedimentary rock. Since the sedimentation process doesn’t chemically change the atoms, radiometric dating isn’t really an effective tool to date sedimentary rock. It doesn’t tell when the sediment changed into rock, and thus other dating methods than radiometric dating would need to be used. This means that radiometric dating cannot tell you when the biblical flood happened, we are taking a wrench to a screwdriver problem.

Correct me if I’m wrong…

I'd also recommend familiarizing yourself with basic concepts of geology (if you aren't already). Superposition, lateral continuity, inclusions, faunal succession, original horizontality, and cross cutting relations.

No one interested in geology should ever begin with things like radiometric dating. I feel like YECs intentionally focus on weird topics that really are kind of secondary to geology and they just confuse a lot of people.

In my opinion, realistically, radiometric dating will never make sense to anyone who doesn't additionally or first have a fundamental understanding of the principals of geology.

It's like trying to understand things like free will vs determinism, or trying to debate catholicism vs protestantism without first reading the gospel. YECs try to jump straight to oddly complicated topics without first just talking about basic concepts of geology. And it's in those basic concepts that YEC positions are essentially dead on arrival.

Then additionally, it would be useful to be familiar with how to read geologic maps and cross sections, so that you can enable yourself to understand what it is YECs are actually trying to communicate. And once you are self sufficient, most people quickly see through the noise to understand the subject on a more technical level.

If you can't get read something like a geologic map or geologic cross sections, then there is really no point in skipping ahead to things like particle physics and chemistry.

 

[Job 33:6]

And another gripe that I have, sorry I have to get this off my chest, is that radiometric dating, if people engage in a discussion of physics and chemistry without first having a fundamental understanding of geology;

It's kind of like doing math, without seeing the tangible real world materials behind that math.

Like if you have a complicated math equation, people could try to debate calculus or debate physics equations to re-orient someone's opinion about what the answer to an equation is. But if I had two apples, two tangible objects. And I told you that 2 apples + 2 apples = 4 apples, you have something behind the math that you can tangibly think about, so that you understand why that math makes sense.

But without geology, if everyone is just going around debating calculus formulas of radiometric dating, and chemistry and atomic numbers and yadda yadda, then the average lay person is not going to have any idea what you're talking about.

And I think that YEC organizations are notorious for trying to bypass the obvious tangible stuff, and they go straight for the technical mathematical and physics aspects, intentionally because they can get away with it when presenting to lay audiences.

But if people just took time to look at the plain and simple geology of the earth, it becomes apparent that YECs tend to just make stuff up that has no basis in tangible reality.

Kind of like the Catholic Church arguing for geocentrism back in the 1600s. People can debate calculus of the solar system all day, but the moment you actually use your eyeballs and look at the subject (like through satellite imagery), the whole geocentric position instantly falls apart.

And early flood geologists of the 1800s noticed this, and they swiftly abandoned their positions, long before radiometric dating ever existed.

And so I think that groups like AiG intentionally target these more technical areas, only because they can get away with it because it oftentimes doesn't involve actually looking at tangible concepts backgrounding the math.

And if we look at these, tangible concepts that underlie geology and then we go go over to the claims of these ministries, these yec ministries, we find that the things they say really just don't make any sense even at the most fundamental levels. They might use technical words to make their ideas sound professional, but their arguments, when you remove the veil, you see that none of it adds up.

Kind of like applying presuppositional apologetics to science. With assumptions not grounded in evidence, but rather assumed by necessity of their upbringing.

 

[Hans Blaster]

And another gripe that I have, sorry I have to get this off my chest, is that radiometric dating, if people engage in a discussion of physics and chemistry without first having a fundamental understanding of geology;

It's kind of like doing math, without seeing the tangible real world materials behind that math.

Like if you have a complicated math equation, people could try to debate calculus or debate physics equations to re-orient someone's opinion about what the answer to an equation is. But if I had two apples, two tangible objects. And I told you that 2 apples + 2 apples = 4 apples, you have something behind the math that you can tangibly think about, so that you understand why that math makes sense.

But without geology, if everyone is just going around debating calculus formulas of radiometric dating, and chemistry and atomic numbers and yadda yadda, then the average lay person is not going to have any idea what you're talking about.

Basic radiometric dating isn't too hard to understand and with organic artifacts and radiocarbon, you don't even need geology. Most people should have seen it by the end of HS. (Even if they forgot it.) But...

And I think that YEC organizations are notorious for trying to bypass the obvious tangible stuff, and they go straight for the technical mathematical and physics aspects, intentionally because they can get away with it when presenting to lay audiences.

But if people just took time to look at the plain and simple geology of the earth, it becomes apparent that YECs tend to just make stuff up that has no basis in tangible reality.

Kind of like the Catholic Church arguing for geocentrism back in the 1600s. People can debate calculus of the solar system all day, but the moment you actually use your eyeballs and look at the subject (like through satellite imagery), the whole geocentric position instantly falls apart.

And early flood geologists of the 1800s noticed this, and they swiftly abandoned their positions, long before radiometric dating ever existed.

And so I think that groups like AiG intentionally target these more technical areas, only because they can get away with it because it oftentimes doesn't involve actually looking at tangible concepts backgrounding the math.

... The professional creationists, like AiG, deliberately choose to muddy the water with anomalies, etc. (like 40kya wood in a 20 Mya rock) and that gets into geochemistry, contaminations, etc. I'm a mere physicist who last dealt with rocks in class in Jr. High, so I'm good with the nuclear decays, but not even close to fully informed on the other complications.

 

[Job 33:6]

I'll say this as well, even from the position of scripture and biblical studies, YEC is completely imaginary.

Genesis 1:1-3 NRSVUE
[1] When God began to create the heavens and the earth, [2] the earth was complete chaos, and darkness covered the face of the deep, while a wind from God swept over the face of the waters. [3] Then God said, “Let there be light,” and there was light.

Many Bible translations simply say, when God began to create the heavens and the Earth, the Earth was formless and void.

Which in very plain English, is a past tense concept. The Earth was, as in already, chaos or formless and void.

And so the Earth was already there before God even began creating.

And they'll say, well God created in 6 days, and they'll repeat this.

But then when you agree and you point out that the Earth was created on day three and the heavens on day two, and you affirm that the creation happened in 6 days (ex materia) and not in verse 1:1 (ex nihilo in 1 day), they backtrack and say "well wait wait, God wasn't actually creating anything on day three because that's ex-material creation not ex nihilo. God couldn't possibly create the earth on day 3 because it was already [allegedly] created in verse 1:1".

Removing water off of land, to reveal dry land is not ex nihilo creation. Because remember, the Earth was already there in verse one.

So YECs trip over their own words and get confused about the Bible itself.

In Genesis, God created the heavens and the Earth in 6 days, not in verse 1 in one day. It's ex materia over 6 days. Not ex nihilo, on day one.

And then they'll say, "God creates with the spoken word", and they'll repeat this. Okay well when does God speak in verse one? God doesn't speak until verse 3. Again, because the Earth was already there.

And so these YEC ministries, they actually have to ignore all these other Bible translations that directly contradict what they say.

And that's all completely aside from their denial and ignoring of ancient Israelite cosmology in Genesis.

It's all just complete denial, it doesn't make any sense from a scientific stance, and it requires the denial of scripture itself.

 

[Job 33:6]

Basic radiometric dating isn't too hard to understand and with organic artifacts and radiocarbon, you don't even need geology. Most people should have seen it by the end of HS. (Even if they forgot it.) But...

... The professional creationists, like AiG, deliberately choose to muddy the water with anomalies, etc. (like 40kya wood in a 20 Mya rock) and that gets into geochemistry, contaminations, etc. I'm a mere physicist who last dealt with rocks in class in Jr. High, so I'm good with the nuclear decays, but not even close to fully informed on the other complications.

Yea exactly.

I think people just confuse The subject with a culture war. Well I'm Republican so that means I need to be a young Earth creationist. Otherwise, I'm a liberal compromiser.

Culturally, evolution is a taboo topic, so I guess that means that Ken ham must be right.

 

[Mountainmike]

Radiocarbon is only useful at all on dates up to several half lives
It is inappropriate for millions of years.

It is indicative , not definitive.
it also depends what is being tested


So stated the ONLY archeologist involved in the shroud project ( meacham) noted from a mass of experience of dating errors. It cannot be used in isolation . It corroborates other evidence.

It needs many empirical adjustments, for example for diet On animal remains.

On textiles it can be very suspect eg . eg Mummies much younger than the wrappings !



The shroud is a serious warning on the validity of RC on textiles.

RC needs proper blind controls and validation. It is invalid without,

On an anciebt fabric test done a year before the shroud test by TIte and the same RC labs showed. AMS made horrendous errors. It should never have been used on the shroud, the machines failed basic equipment qualification,
It was conveniently ignored in violation of all good practice.

The results of the shroud failed basic audit trail and homogeneity.
the outcome was statistically invalid. There was no date.
the results were then fiddled for Nature!

Atheists ditched all scientific integrity when analysing the shroud.
they made all the mistakes you can.

but as meacham - the ONLY archeologist involved said in the period leading up to it, RC is indicative not definitive.