Truth in the Text Part III – Just How are Rocks and Bones Dated?

How do we reconcile a 6,000 year old earth with all the data showing ancient bones, fossils and rocks at far older ages? I can’t say I ever really questioned it in years past, just assumed God created the earth in an already mature state. Adam, for example, was formed as an adult, and the trees in Eden were mature and fruit bearing. Why not rocks with inherent age? What is that to God?

Lately I’ve been looking into the research, however, and discovering some interesting perspectives. It’s good to question, to search for answers. God’s Word is truth, bottom line, but He doesn’t ask us to believe in a vacuum.

Scientific research relies on assumptions. It has to. There have to be parameters from which to begin hypothesizing. Gravity, for example. Any research on rockets has to assume gravity will continue to fight flight in a predictable and measurable manner. The developer of a new medication has to assume certain chemicals will continue to behave as they have in the past, raising blood pressure, inhibiting infections, etc. These assumptions are based on experimentation that can be observed and reproduced.

When it comes to estimating the age of something formed in the past, assumptions are essential. No one has a time machine. No one can go back and watch it actually occur. This is where the contradictions lie between scientists who believe the earth is billions of years old and those who believe it’s around 6,000 years old.  The actual testing isn’t so much a question as are the assumptions the results are based on.

To get to these assumptions, I want to take you through science class again. It’s fascinating stuff, really, especially if you believe in a Creator. There’s an intricate organization to the universe that is simply magnificent.  If you are already kicking and screaming, you can skip waaaay down to “Putting It All Together,” then go enjoy recess

How samples of bone, rock, fossils, and such are dated.

One method used to date old bits of matter is called radiometric dating. In a nutshell, radiometric dating measures how long specific elements (like oxygen or uranium) in a given sample (of bone, rock, etc) have been breaking down and forming specific new kinds of elements.

Here’s how it works: Everything is composed of atoms. Atoms have three kinds of particles: Protons, neutrons, and electrons. The number of protons determine what kind of element it is. For example: oxygen always has 8 protons, carbon always has 6 protons. The number of neutrons in the atom can vary a bit, giving us isotopes, or forms, of the element. Take Carbon. It has 6 protons and either 6, 7 or 8 neutrons. The isotopes are labeled Carbon-12 (C12), C13, and C14. (Did a bell go off in your head? Sorry, it isn’t the end of the school day bell. I was hoping Carbon-14 sounded familiar.)

Some isotopes are stable (happy with themselves) and some are unstable (radioactive), wanting to break down into something else. C12 and C13 are stable. C14 is unstable. It wants to shake its particles around and change things up a bit, eventually turning itself into Nitrogen-14, which is stable.

This rate of decay from C-14 to N-14 is a known, measurable rate.

In this example the C-14s are called the parents and the N-14s, the daughters. The numbers of both are calculated in the sample. If the number of parents originally in the sample is known, and if all daughters were produced by decaying parents, and we know how fast that parent decays, then we can figure out how long it took for all the daughters to form. (Well, a math whiz can anyway.)

So geologists use C14 dating to date rocks, right? Nope. Rocks don’t contain carbon. Only once living organisms have carbon. There are five other parent –daughter isotopes use to date rocks. For now, we’ll stick with C14 and what it tells us about the age of our earth.

Just a bit more textbook:

Q: What CAN be dated with C14?

A: Anything that lived/lives, namely plants, animals, birds, fishes, humans, reptiles and insects. Anything made from them, too, like linen and wool fabrics, bone weapon handles, oil and diamonds (as long as there is still actual biologic material remaining and the sample is less than 60,000 years old.)

Q: Where does C14 come from?

A: Cosmic rays from the sun bombard the Nitrogen-14 in our atmosphere and force some of it back into C14. It combines with Oxygen to form Carbon Dioxide.

Q: Then what?

A: Plants utilize radioactive Carbon-14 just like they do regular Carbon-12. Animals eat the plants and humans eat the animals as well as the plants. We take the C14 in to our bodies eating everything from Cheetos to tofu. It does its thing and turns into Nitrogen. There is a continuous cycle of taking in Carbon and it becoming Nitrogen. The concentration of C14 in all living organisms is the same as in our atmosphere

Once the organism, let’s say a moose, dies, his C14 intake stops. Scientists know the amount of C14 in the air so they know how much is in the moose at the time of death. That amount of C14 in the moose will decrease over time because the unhappy Carbons still want to be Nitrogens. So the longer the moose has been dead, the less C14, and the more N14, he will contain. After about 60,000 years there won’t be enough C14 left for accurate dating.

ROCKS are dated the same way, only with different parent-daughter isotopes. The five pairs used for geologic material have decay rates that allow dating of samples far older than 60,000 years.

Got it?

There are definite inconsistencies in Radiometric Dating so the method holds some controversy among scientists, but overall is accepted in the research community.

Q: How, then, do creation scientists explain human bones found in Japan dating back 24,000 thousand years? And what about those billion year old moon rocks?

A: I found various reasoning in the literature. It seems there is one point, one assumption made with radiometric dating that causes the most concern:

ASSUMPTION: The concentration of parent atoms in the atmosphere is the same today as it was when the sample was formed/died.

Scientist need to know the starting volume of the parent to calculate decay rates and estimate age. They use the current atmospheric concentration. But what if the starting volume was less concentrated than now, or more? Then the estimated ages are wrong.

Carbon levels are not a constant. Our industrial revolution and atomic testing proved that. And the earth’s magnetic field (shielding us from the majority of those cosmic rays that facilitate C14) is 10% weaker than 150 years ago when testing began. The weaker the shield, the more C14 produced. Has it been getting weaker over a long period of time? Does it go up and down? I don’t know. I found articles claiming both and will discuss them in Part IV.

If the field has been weakening, as suggested by some creation scientists, then C14 long ago was lower, when the field protection was greater.  A sample of matter from the past will therefore start with fewer parent atoms. That sample tested by today’s concentration will appear to have been in the C14 decay process for a greater period of time. 


* Many tests performed in the quest for knowledge give accurate results, but assumptions that go with them may not be. With all the technology available, it is still man left to interpret the data.

* The long-ago concentrations of Carbon-14 and other radioactive isotopes used in radiometric dating are unknown. Some scientists say they have not changed over time and some say they have increased significantly since the flood of Genesis. There is no jar full of air on a cave shelf that we can pull down and test. This uncertainty affects the accuracy of test results.

* Radiometric Dating is still highly useful to show us relative ages of organisms and rock layers, compared to one another, taking into consideration that the dates may misrepresent the actual ages.

* What does God say? He formed it all 6,000 years ago.  And no tests, no theories, no mind of man will alter that truth.

As for God, his way is perfect; the word of the Lord is flawless.
He is a shield for all who take refuge in him. For who is God besides our Lord?
And who is the Rock except our God?
(II Samuel 22:31,32)

NEXT TIME let’s lighten up! We’ll talk about dating dinosaur bones, and the Shroud of Turin, and why Methuselah got to have 969 birthday parties, and how the flood could change how we interpret tests performed today.

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Posted May 8, 2012 by Rachel in category "Genesis


  1. By Deborah on

    Your book was wonderful. And this lesson regarding carbon dating was timely for me. Recently I had a conversation with a very dear friend about this very subject. He is a scientist-attorney and an agnostic. We stayed up until the wee hours discussing my faith and his lack thereof, and the Earth’s age was a subject for which I was woefully unprepared to argue. I know what the Bible says and what I believe, but it’s good to also argue science with a scientist. Like Issac saying the earth was round and the universe (Heavens) were expanding thousands of years before man and science discovered it was so. Thank you presenting the info in an understandable form, (and enjoyable to read, too). I have been looking for an answer and I knew The Lord would provide if I would seek, and of course, He did.

    1. By Rachel (Post author) on

      Deborah, Thank you for taking time to write. I love studying young-earth apologetics and want to make the science fun and interesting to others. Check out the Answers in Genesis website for tons of info and a great online bookstore, too. I will pray that your friend is open to more discussions and the Holy Spirit will provide the words and the passion that capture his heart. God bless you!

  2. By Paula Messmer on

    Wow! You are setting yourself up as a teacher! I learned a lot from this article – especially since I didn’t know what carbon “14” dating was. I hope I can remember one snippet of it. You’re amazing and such a good writer – you made this understandable to a very non-scientific brain. Keep up the good writing. Next article – sounds interesting, too.

    1. By Rachel (Post author) on

      Thank you Paula! I’m enjoying the research for this series, hope to keep it going for a while. I really appreciate your support!


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