WORLD HISTORY
And
RADIOMETRIC DATING
PART LIII
Hello everyone! Hope all went well this past week. It has been very busy and hectic here but I always enjoy the buys life!
If you remember from last week, according to the science dictionary (http://dictionary.reference.com/browse/radiometric+dating?s=t), radiometric dating is defined as “radiometric dating (rā'dē-ō-mět'rĭk)- A method for determining the age of an object based on the concentration of a particular radioactive isotope contained within it. For inorganic materials, such as rocks containing the radioactive isotope rubidium, the amount of the isotope in the object is compared to the amount of the isotope's decay products (in this case strontium). The object's approximate age can then be figured out using the known rate of decay of the isotope. For organic materials, the comparison is between the current ratio of a radioactive isotope to a stable isotope of the same element and the known ratio of the two isotopes in living organisms. Radiocarbon dating is one such type of radiometric dating.” (bold emphasis mine).
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| FROM ANSWERS IN GENESIS |
We saw how the bolded portions of the definition are assumptions, so how does one “Find a “Date”.
“Most people think that scientists can actually measure the ages of rocks, using a method called “radiometric” or ‘radioisotope’ dating. More often, rocks are “dated” by the fossils they contain, based on a pre-existing belief in evolution. But even radiometric dating does not actually directly measure the age of something (there is no substance called “age”). It measures the amounts of certain radioactive substances. This information then has to be interpreted, based on certain beliefs.
“In fact, most fossils do not even contain radioactive minerals. So if scientists wanted to measure the age of a fossil using this method, they would look for a nearby layer of igneous rock (e.g. rock that forms from lava from a volcanic eruption)—perhaps in the rock layers above where the fossil was found, or in the layers below. When they find one, they gather a sample of the hardened lava and send it off to a laboratory to test it for radioactive elements.”1
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| FROM ANSWERS IN GENESIS |
But we do get a measurement….a date. The question is, is it an accurate date. The lava rock can seem very, very old. The scientists who interpret the amounts of A and B often conclude that millions of years have passed because they first assume three main things about the rock:
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| FROM ANSWERS IN GENESIS |
- “How much A and B was in the rock when it hardened.
- A has decayed into B at the same rate over the years.
- The amount of A or B in the rock has not increased or decreased in any other way.
- If B was in the rock before it hardened.
- If A has always decayed at the same rate.
- If water, for instance, has removed some A, or carried some B into the rock from elsewhere.
“All of these factors will affect how “old” the rock appears—in practice, usually making it appear a lot older than it really is.
“To test this method, some scientists gathered samples from hardened lava at Mount St Helens, which erupted most recently in the early 1980s. The samples, which came from rocks that formed between 1980 and 1986, were sent to a lab and were “dated” using the potassium-argon (K-Ar) method. The test results ranged from between 340,000 to 2.8 million years old!
Other scientists collected samples from cooled lava flows from Mt Ngauruhoe, in New Zealand. These rocks are known to be less than 50 years old, because people observed the volcano erupting in 1949, 1954 and 1975. But the lab results indicated that the rocks were up to 3.5 million years old!
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| MOUNT ST. HELENS |
“If this method doesn’t work on rocks the ages of which we know, how can we trust it to work on rocks of unknown age?
Here is another example of other volcanos of known dates of eruptions and the fallible dating method:
(Answers In Genesis)
Here is another example of other volcanos of known dates of eruptions and the fallible dating method:
| Volcanic eruption | When the rock formed | Date by (K-Ar) radiometric dating |
|---|---|---|
| Mt. Etna basalt, Sicily | 122 B.C. | 170,000–330,000 years old |
| Mt. Etna basalt, Sicily | A.D. 1972 | 210,000–490,000 years old |
| Mount St. Helens, Washington | A.D. 1986 | Up to 2.8 million years old |
| Hualalai basalt, Hawaii | A.D. 1800–1801 | 1.32–1.76 million years old |
| Mt. Ngauruhoe, New Zealand | A.D. 1954 | Up to 3.5 million years old |
| Kilauea Iki basalt, Hawaii | A.D. 1959 | 1.7–15.3 million years old |
“After examining the assumptions behind this “dating method”, and doing scientific experiments to see if this method works on rocks of an already known age, we find that “radiometric dating” isn’t all it’s cracked up to be. (Actually, any process used to find ages for things is based on assumptions, and so is not reliable.) It’s important that we allow God’s written record of history, the Bible, to guide our thinking about the past—this includes our understanding of the age of the Earth/universe and the age of fossils.”3
Until next time, tally-ho!
Willow Dressel
This week in the night skies for both hemispheres; on Feb 26 the moon will appear near Venus and just two days later on the 28th, it will appear near Mercury.4
References:
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