Of Rocks and Romance: Radiometric Dating

When a scientist discovers a fossil, one of the first things they do is an attempt to date it. However, when a scientist dates a fossil, he does not take it out for dinner or to the movies. Instead, he sends it to a specialized laboratory to have special radiometric tests done on it. It is a bit of an odd romance. In this article, I’ll be discussing how radiometric dating works, why evolutionists rely on it and how it affects the origins debate.

In order to understand radiometric dating, some background information is necessary.  There are numerous types of radiometric dating but most rely on similar methods. Essentially all matter consists of various atoms of numerous different types, such as Carbon, Oxygen, Hydrogen, and Iodine.  Each of these atoms has what is called an atomic number, indicating the number of protons in the nucleus of the atom.  Some atoms exist in more than one form, called isotopes. When such an isotope exists, it is differentiated from the standard atom by writing the number of neutrons and protons in the nucleus in superscript next to the elements atomic symbol. Each individual isotope is called a nuclide.

With the basic background out of the way, let’s talk about how radiometric dating actually works. Some nuclides are unstable in their formation and decay into the more stable nuclides.  The amount of time it takes for half of the original or parent nuclide to decay into the resulting nuclide or daughter nuclide, is called a half-life. A half-life of a given nuclide can be estimated based on the rate it decays in the present. There is an equation for determining the half-life of a given nuclide which is below.


The T represents the half-life of a given nuclide. The odd looking symbol is the decay constant.  Having either the decay constant or the halflife allows you to calculate the other with ease. Halflives are usually measured in years.

Radiometric dating works by calculating the rate of decay of a given nuclide. That means that they are looking for the decay constant, using a known half-life. This allows scientists to determine how long a given piece of rock has been in existence. If the half-life is unknown, it can be determined by observation in the lab before attempting to determine the decay constant.

Evolutionists love radiometric dating. They rely heavily on it to prove that the earth is millions of years old. Every fossil they unearth, they date using some form of radiometric dating. Usually, this is Carbon-14 dating, though other methods of dating are used as well. If you were to examine science textbooks, when you find a fossil discussed with a date, it will almost exclusively be determined by using radiometric dating.

There are, however, a multitude of problems with radiometric dating.  The first problem is halflife itself.  The half-life observed in the present is assumed to be constant in the past. This is a huge problem since the past is an unknown variable. Under different atmospheric conditions, such as the lack of rain before the flood, the half-life could have been different. If the halflife is in-consistence at all, under any conditions, then the equation goes out the window. The halflife must always be consistent. If it varies at all, then the rest of the equation can no longer be consistent either, which makes the resulting date questionable.  Evolutionists even acknowledge this, as it is possible for the radiometric “clock” to be completely reset by being heated to something called a “closure temperature.”  This makes it clear that it is unwise to assume a consistent halflife. However, this is not the only issue with radiometric dating. It requires a second assumption, that being that the amount of the parent element and daughter element in the fossil have not been changed. Suppose we are talking about potassium-argon dating. Once the rock was formed, no outside potassium or argon can be added for radiometric dating to work. If either the parent element(potassium) or daughter(argon) element is added or lost before the rock is tested, the resulting data will be incorrect.  A third assumption is that the universe is at equilibrium. In other words, for radiometric dating to work, the rate of daughter element formation must be equal to the rate at which it decays. In most cases, the rate of formation is much faster than the rate of decay.  This is a problem because it skews the amount of the parent element too high. This will result in an incorrect age for the rock.

Creationists do not reject radiometric dating when used appropriately. For example, C-14 dating is fairly accurate within six thousand years. However, anything beyond that it begins to lose accuracy. Evolutionists base their entire timeline on the support of radiometric dating, but, as we have seen above, it is riddled with assumptions and problems and this article barely scratched the surface.  If there is interest, I may post more in-depth articles about the various types of radiometric dating and their issues.






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