**Question:**

**Do Dating Methods Prove an Old Earth? Beverly Flori**

**Answer:**

You have probably heard that radiometric dating has “proved” that the earth is millions, or even billions of years old. Can these dates be trusted?

In radiometric dating, there is a “parent” isotope which changes into a “daughter” isotope over a period of time because of radioactive decay. If you know the “half-life”, how long it takes half of the parent isotope to decay completely into the daughter isotope, you can theoretically calculate the age of the rock that contains the isotopes.

However, every dating method begins with assumptions. In the case of radiometric dating, there are at least three. The first concerns how much of each isotope was present at time zero when the rock was formed. It is assumed that 100% of the parent isotope was present and none of the daughter isotope. However, no geologist was there to make measurements when most rocks were formed, so we do not know if the amounts were truly 100% and 0%. Without knowing the starting conditions accurately, we can’t make an accurate calculation.

The second assumption is that during the entire “lifetime” of the rock or the entire decay cycle there was no contamination. Contamination could cause gain or loss of the parent or daughter isotope, throwing the age calculation off. The third assumption is that the decay rate must have been constant during the entire decay period, but there is evidence that decay rates have not always been constant. As you can see, if the assumptions are incorrect, then the calculated ages of the rocks cannot be trusted.

Let’s look at some specific examples of dating rocks of known age to see how reliable radiometric dating is. In these cases, potassium (K) is the parent isotope and argon (Ar) is the daughter isotope. A Hualalai, Hawaii volcanic basalt rock formed about A.D. 1800 (just over 200 years ago) was dated by potassium-argon (K-Ar) radiometric dating to be 1.32 – 1.76 million years old. A volcanic rock formed in New Zealand in A.D. 1954 (just over 60 years old) was K-Ar dated up to 3.5 million years old. An A.D. 1986 lava sample from the Mt. St. Helens eruption (only about 30 years old) was K-Ar dated 350,000 – 2.8 million years old! Hmm! How does a known date of 200 years compare with a radiometric measurement of 1.32 + million years? How does 30 years compare with 350,000 + years? These are not accurate measurements! So if we can’t trust radiometric dating on rocks of known age, how can we trust it for rocks of unknown age? Beware of believing the “millions and billions of years” theories!

For more information on dating methods, please go to www.answersingenesis.org. Type in “Age of the Earth” or “Radiometric Dating” in the search bar to read more articles on this subject.

**References:**

Bodie Hodge, “Can Radiometric Dating Be Trusted?”

__The Evidence Bible,__p. 674.

Andrew A. Snelling, “Radiometric Dating: Problems with the Assumptions”,

*Answers*magazine, Oct. – Dec., 2009, pp. 70-73.