Originally posted by sergeanthulka:
Thumper:
Regarding Carbon 14 dating. Do you deny that - to say Carbon 14 dating is accurate - that it depends on the following 3 assumptions?
1) There has always been as much carbon 14 in the atmosphere as there is today.
2) Carbon 14 has always decayed at the same speed.
3) All living things absorb the same amount of carbon as the atmosphere has in it
Do you deny that any of these 3 assumptions are open to scrutiny or variance of opinion?
Okay, let's do this. But first let's recall what you said to me in another thread.
Originally posted by sergeanthulka:
If you're gonna run with the big dogs, Sal...you're gonna have to break down & read the whole thread...
I'm going to have to say the same thing to you here, if you're going to run with the big dogs on this issue you need to educate yourself on the nature of radioactive decay.
So, here we go.
1) There has always been as much carbon 14 in the atmosphere as there is today
No. What is actually important is the ratio of Carbon 14 to Carbon 12. Everything is calculated based on this ratio.
Now about the amount of Carbon 14 being constant. Carbon 14 is formed in the atmosphere by cosmic rays interacting with Nitrogen 14. This reaction rate is not constant, but rather is affected by supernovae and things of the like. But it has been shown that these event cause fluctuation in the data of only + or - 10% at most. We can also assume that a constant radiation background of cosmic radiation existed in our galaxy (other than the supernovae and like events) for millions of years based on models that are derived completely irrespective of this model.
Now this carbon 14 combines with an oxygen molecule to form CO2, and stays in the atmosphere. When the Carbon 14 decays it becomes nitrogen again and leaves the oxygen. This cycle forms a steady state where the rate of decay matches the rate of formation of C 14 by the cosmic rays.
2) Carbon 14 has always decayed at the same speed.
This is not an assumption but rather a derived principle. The rate at which Carbon 14 decays is not determined by what we measure, rather that is just an experimental verification of the quantum mechanical theorems.
One can completely derive the decay rates of any Isotope by solving the Schrodinger equation for the atom. The variables in the Schrodinger equation depend only on the energy interactions of the nucleons, these energy interactions are dependent
only on the positions of the nucleons relative to each other. For carbon 14 to exist, each of it's nucleons
must have the same postition probablility or the nucleus would not form. Thus carbon 14 would be the same thing 2 billion years ago as it is now. Its formation and its decay depends only on the energy interaction of the protons and neutrons, these things are
not a function of time.
3) All living things absorb the same amount of carbon as the atmosphere has in it.
No one takes this position with the word
All in it. Nearly all organisms do. But there are certain forms of organisms that consume carbon in other ways, I believe I've read mollusks feed on some other form of carbon and thus have a different ratio in their body.
It has been experimentally proven that a vary wide range of organisms that do in fact take in the same
ratio of carbon as the atmosphere has in it.
Besides this is a mute point, even if there are some renagade organisms that don't take in the same ratio of carbon there are plenty we know that do, and we can focus our testing on those organisms. For example, people. People have been on this planet far longer than the effective range of carbon dating. We know people consume the same ratio of carbon as is in the atmosphere, so we can accurately determine the age of human fossils throughout the effective range of carbon dating.
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Besides Hulka, there are plenty of radioactive dating techniques that use the decay rates of other elements such as uranium. These things have effective ranges of billions of years. What silly contentions are you going to make about those techniques?
This post was edited on 4/27 5:16 PM